FIRST LIGHT
Photography Workshops

SENSOR CLEANING
By Andy Long

This is a new hot button topic for digital camera users. Yes, there are still some film shooters out there as I had one on my northern lights trip. Numerous companies have come out with devices designed to clean your camera's sensor. Some are good, some not so good.

In its latest camera body release, Canon now has two bodies with self-cleaning sensors. They first tested it on the Rebel XTi consumer model to see what bugs needed updated. They now have it on their newly announced 1D Mark III body, which will sell for around $4,000. From the material I've read, this is going to be a great body. If you were looking to get a new body, wait a short while because there will probably be a lot of good used 5D's and 1D Mark II's hitting the market pretty soon.

And if you really want a great body for doing landscapes and nature, although it's not officially announced, Canon will be coming out with a 22 megapixel camera later this year. Price will be more than $8,000.

Back to sensor cleaning. I have been using the Arctic Butterfly brush to somewhat decent results. I would use by rocket blower first, the brush, then the blower again. This seemed to do a pretty good job. There are also several kits with a cleaning solution and swabs. The LensPen can also be used to clean the sensor but be aware that it can't reach into the corners as it is round. Make sure you use the LensPen only for the sensor. If you have a LensPen you use for cleaning your lenses, get another one for use only on the Sensor.

Delkin has recently come out with the Sensor Scope. While it uses the cleaning solution with swabs, it has a couple of extra features that make cleaning a multi-step process. The best thing about this packet is the scope that comes with it. It fits over the opening on the camera body where your lens goes and has a light that illuminates the sensor, showing exactly where you have some dust that needs to be removed.

Cleaning can be a one or two-step process. There is a small vacuum that comes in the kit that you can use to get just a spot or two of dust off. If after using the scope again and you see dust, you can then use the swabs and solution to do a thorough cleaning. If possible, try to conserve your use of the swabs as packets of these replacement items will run up the cost over time.

Whatever option you use for cleaning your sensor, be very gentle as you definately don't want to scratch the sensor as this is a very pricey item to get replaced / repaired from the manufacturer.

A good test to see you might have dust if you don't have a scope it to take a picture of a crisp blue sky and blow up the image to 100% in Photoshop and look everywhere to see where you might have some dust.

If you're interested in getting a Sensor Scope kit contact me as I can get these for you at a much better price than at any retailer. The markup on the kits is quite high, so I'll be able to save you a good chunk of change.

All of these products are very soft and do not damage the sensor. I have used all methods and have not had a problem with doing this. You have to be gentle, though. Don't be rough with how hard you apply pressure on the sensor.

DIGITAL IMAGE ORGANIZATION
By Bob Dean

Life is good. No more film costs, processing fees, postage or trips to the lab, because digital photography enables us to shoot a lot of images essentially for free. With this great improvement in “image acquisition” comes added work after we come in from the field. In June the digital corner highlighted a new software tool for workflow. This time we take a look at some ideas on improving organization of all of those images we made for free. Organization and workflow are pretty closely tied together. If you know how your images will be organized, you can adapt the workflow process to make your computer time more efficient. Let’s consider some basic workflow and organization ideas.

The very first thing you need to do is an initial edit of your images to weed out the obvious bad ones. This first edit could be done with the LCD on the camera or a software package looking at the CF card before download. It should be really quick and weed out grossly out of focus, poor composition and bad exposure. This will then allow you to concentrate on the images that have a chance of making it to your permanent files.

After this initial edit, you are ready to download your “shoot”. But wait a minute! Have you decided how you want to file your images? The concept of file organization is boring but with a little planning you’ll be able to locate images in the future. One good way to set up (or convert your existing file structure) is to look back to how you stored images when they were on 35mm film. If what you did back then was good enough for your needs, you could create a file structure quite similar to that for your digital images. I used 3 ring binders and archival sleeves for my images and labeled the binders according to the content. Some examples are large mammals, small mammals, insects, wildflowers, etc. This worked pretty well as I had a list on my computer that had highlights of what was in each book. When I went digital photography in a big way, I kept that same basic concept but decided to use Windows™ ability to build multi level file structures to provide what amounts to binders with tabs and then sections with in each tab. Windows™ allows file names up to 256 characters so you can get a lot of descriptive information in the file name.

Here is a simplified version of my file structure:

You can see that with just 5 levels you can really get some detail. Windows™ allows nesting of file well beyond 5 levels. A really good website on file structure is:
http://www.itc.virginia.edu/desktop/docs/fms/pc/organize.html

Once you have you files organized, you can add additional folders at any level. Say you have never photographed wild horses before, but on a trip to western Colorado you got some great shoots. Simply add a new folder under the large mammal folder for wild horses. Note that Windows™ will arrange your files in alphabetical order so takethat into account when you set up your files.

I’ve found it best to create new file folders before downloading from a CF card. I can then specify the location to store the files when I do my download. Since I use Lightroom™, I can specify the import location, then bring my images in from the memory card and do a second edit on a larger screen, add location information, key words and metadata, and group images by quality.

Before your next big shoot, take some time to organize your files. The longer you wait, the more you’ll need to move around.

DATA MANAGEMENT
By Bob Dean

Data management is the industry buzz word for how you handle the images you have in digital format. Data management starts with selection of memory card size and goes all the way through the file structure and the back up process you develop. These decisions are really driven by the type of shooting you do. Consider the following notes and decide what fits your needs.

1) Select a memory card size that meets your needs. I personally feel that either 1 or 4 GB is a good size. These hold up to a few hundred images in RAW format. Anything bigger could mean that your entire two week trip is on one card and could be lost or damaged. Anything smaller means you have a lot of cards that may get lost.

2) If you’re on a long trip using more that one or two cards, once you fill a card you have the choice of transferring it to a laptop or other portable device OR carrying enough memory cards so you can bring home your images on the cards. These cards are very rugged and immune to things like airport x-ray machines. Prices are dropping so this is much more of a realistic approach than it was just 2 years ago. As with any decision the “pros” have a variety of opinions. Some just use the cards; others make two or three copies on DVDs or other more permanent memory devices. I like just using memory cards.

3) Once you do get home, you really do need to consider your storage plan. A key decision is back up. Backing up data can be summarized in two words “DO IT”. Computer hard drives are electro-mechanical devices that will fail – some day. Now the question is what is the right way to back up data?

4) A starting point is to do a quick edit of your images as we discussed last month. Then with your RAW images edited to remove the true discards, store them in a file on your hard drive in the most compact manner you can. I like to do this by trip. Then I copy that entire file to a high quality write once DVD, not a rewritable one, they are much less archival. Make two copies if you’d like. Blank DVDs are cheap and two copies provide good insurance. Keep the two in separate places if the images are really special. Then you can rearrange your files on the hard drive. This is where a good batch processing program (like Lightroom ™) can be helpful. You can annotate each image with the DVD identifier in one step.

5) Now once you have started to do your image processing with Photoshop, you can also make copies on other DVD’s of the resultant jpeg or psd files. That’s up to you, but you’ll have your original RAW images on a fairly archival media. Do remember however that DVD’s are not permanent like old Kodachrome™ slides. They tend to deteriorate so it’s a good idea to rewrite new ones every few years.

COLOR MANAGEMENT- Part 1 (Notes from the Denver NANPA Conference)

Obtaining accurate color in digital prints or on screen is a major frustration for many photographers. An image looks great on screen but when it's printed, the color is not the same at all. Or, you've edited your images to perfection and have posted it on your website or sent it to a client and now it's too dark or bright.

Sound familiar? The first place to start is with your monitor. Unless you have an accurately calibrated display you're only guessing that what you see on your screen is what other people will see.

Monitor calibration software - There are a number of options available for calibration of displays. The Mac includes a software calibration system, and Windows users of Photoshop and Photoshop Elements have the Adobe Gamma utility available. The drawback to using either of these tools is the measuring tool - your eyes. Because you're using vision to set properties, there will always be some variation between the optimal settings and what you perceive to be correct. Still, using software calibration is much better than ignoring your display settings completely.

Mac - These come with the Display Calibration Assistant, which is located under System Preferences Displays. Choose Color and select Calibrate to get started. Use Expert Mode to give you as much control over the process as possible.

You'll go through five steps to determine your monitor's settings, each focusing on different aspects of luminance. The next step is to select a Gamma setting. The Mac has historically used a gamma of 1.8. This give you better shadow detail at the expense of saturation in your colors. Choose the PC Standard setting of 2.2. This is in fact the Native gamma for most LCD displays, including the Apple Cinema displays.

Nest is the target white point setting. Use D65, or 6500 K as the color temperature. This will give you the most neutral and accurate whites possible. Complete the process by giving your profile a name and letting the Assistant set it as the default profile.

Windows - Find the Adobe Gamma utility by selecting Start > Setting > Control Panel > Adobe Gamma. This works much like the Mac tool where you set the luminance values by making adjustments to red, greem, and blue boxes on the screen. Be sure "View Single Gamma Only" is not checked and the "Desired" setting is "Windows Default" which is 2.2.

Now, make adjustments to the three color boxes until the solid and striped areas blend as much as possible. Next, set your "Hardward White Point" to 6500 K, and "Adjusted White Point" to Same as Hardware. As with the Macintosh utility,. you'll save this profile and it will automatically be used by your system.

Considerations for screen to printer include:

1) RGB on a monitor is active color, emitted by a source
2) Printers use CMYK (Cyan, Magenta, Yellow plus black) and it's a subtractive process
3) Printers use 4 colors, even if they have 6-8 inks, the basic four colors are all that's really there.

When calibrating a monitor the Gamma adjustment is better than nothing but far from perfect. Your eyes and ambient light changes can have an effect.

LCD should be calibrated every 1-2 months or when some change is made to the environment, hardware, etc.

A side shield on a monitor is good idea. Reduces ambient light glare

Display resolution should be set to the units native for best images, everything else is scaled. You can find native on the literature or the mfg's website. Set the default to this in Windows - 1280x1024 is common

WHAT'S ALL THE NOISE ABOUT
By Bob Dean

Back in the days of film photography, we worried about grain in our images. It was the wisdom of the time that the faster the film, the more pronounced the grain and the less sharp the image. Exposure times, film processing parameters and such had some impact but that was really a second order effect. The guys in the green and in the yellow boxes were constantly working to improve grain structures to reduce the impact of faster speeds on image quality. That was then, this is now.

The digital revolution has introduced the photographer to the wondrous technologies of electronics and digital signal processing. But, one of the things we now must deal with in our photography is noise, or as some authors call it, digital grain. Let’ discuss its sources and how to deal with it.

What is noise? It’s all of the additional extraneous signals that come from the sensor, the analog electronics and the digital circuits in the camera that show up in our images (and usually have a negative impact on the image). This is particularity visible in images of large single color such as the sky.

Noise has a number of sources. These range from dust on the sensor to the intrinsic errors in converting an analog signal to a digital data stream.

Dust on the sensor is the easiest to understand but can be quite difficult to control. Point and shoot cameras have a pretty good sealed environment around the sensor so dust is normally not a problem, but if you do get dust problems, correcting the root cause can be tough. Digital SLR’s are much more prone to sensor dust but most have a “clean setting” that allows the photographer to blow away dust (carefully!). The other sources of noise are a bit more technical, but let’s start with light striking the sensor. Light comes in little packets call photons. When these little guys strike the sensor they are converted to electrons which are then used to generate the electrical signals containing image data. Since the sensor is warm (that is at a temperature above absolute zero) other “thermal” electrons are generated just by the heat. These electrons create a baseline signal (noise) that contaminates the image information. The signal coming off of the sensor is very small and cannot be effectively used by the circuits that convert the analog data to digital information. To remedy this, analog amplifiers are used to boost the signal. The background noise is amplified as well as the image data plus the amplifier adds its own noise contribution. The amount of amplification is controlled to a large degree by the ISO setting on the camera. The higher the ISO, the more the noise contribution. Higher ISO means the camera will use less light to generate the image. Less light means less signal from the sensor (fewer photons converted to electrons), more amplification is needed and the ratio of signal (image data) to noise is less. This shows up as higher noise or grain in the image.

Another noise source, one that’s easier to relate to film grain is the inherent nature of digital imaging. The process of producing a digital image means we are taking an infinitely variable light spectrum and converting it to discrete pieces of information. The first place is the sensor itself, made up of a fixed number of sensors, not unlike the grains in film. The analog data generated has, as we’ve seen, a noise component. This signal is then once again digitized into discrete pieces of data for processing. Each time this analog to digital conversion takes place, information is lost and edge detail is compromised. When the signal is then compressed into a jpeg file, more information is lost.

So, we have a lot of noise sources. How can we deal with them? The component and camera manufacturers have done very good things to reduce the impact of noise on our images. The first is the development of larger and larger sensors. Larger image sensors have more light gathering capability with a constant noise level. A 6 mega pixel sensor that is APS size generates more effective noise that a larger full frame sensor. The second, and probably most important improvement, is the noise reduction software in the camera itself. This “post processing” activity in the camera (with the RAW data) actually removes a lot of the noise from the signal, producing a cleaner and more grain free image.

What can the photographer do to reduce noise? Well, first use a camera with the biggest sensor you can afford. Unfortunately for the wallet, this usually means a digital SLR. If that’s not in the budget, then shop for the camera with the biggest sensor you can get and do research on the quality of the camera manufacturer’s noise reduction software.

With any camera, the following tips will also help.

1) Shoot at the lowest ISO setting you can for the conditions. Remember, this means less amplification and more light converted to image data.

2) Try to avoid very long exposures. The longer the shutter is open, the more total sensor noise is generated.

3) Use the lowest compression setting you can (high resolution jpeg has less inherent noise than low resolution – but it takes more storage space).

When you do get your images on to the computer, there are several really good noise reduction software packages available. Do some research and see what you can find. More are coming out every day.

Dealing with digital grain is really not that much different from film grain. Learn the causes and the remedies and keep on shooting.

DIGITAL PHOTO RESOURCES
By Bob Dean

We are deeply into the digital age in photography. If anyone is still skeptical, then just do an internet search on DIGITAL PHOTOGRAPHY LEARNING and a search engine like Google will provide over 28 million hits, and that is just the filtered English language sites. Well over twenty million digital cameras were sold in the US in 2005 and the growth in sales is slowing, indicating that the digital camera market is maturing – meaning digital is the standard and film cameras have pretty much been replaced. We are all looking for resources to help with ‘going digital’ or improving our skills in digital photography. This month we wanted to take a look at how to dig out the good resources, both on line and in print, which can help.

First, let’s address the basics. The craft of photography has not changed, just the tools we use. The concepts of composition, exposure, and creativity are as important today as when we used film as a medium. The classic books by the best teachers are still valuable. But where can we go to get help for digital issues such as white balance, noise reduction, etc.? There are literally hundreds of books being written every year on digital photography, and the critics are close behind in evaluating them. Check out the photo magazines or their websites for book reviews. In our investigation, most books are pretty close to each other in what they cover. The standard approach is to set the stage with how digital works, how it differs from film, how to use the digital specific creative controls and then the authors typically go into standard photographic lessons on composition, etc.

Most of the books also address how to fix your images on the computer. We are now seeing a bit of a backlash from the experienced photographers, as they spend more and more time in front of the computer monitor. The hue and cry is to get back to basics, expose properly, compose well, and all of the other stuff we did with film. Then you don’t spend all that time fixing problems that were eliminated in the camera.

But we digress. Before you spend your money on digital photo books, classes, or lots of cool software, try the free information route first. Remember we opened with the tens of millions of Google hits? Well, here are a few that we found had good, free information, tips and ideas. Some of these are pretty basic, some get into quite a bit of detail and several provide additional links for more information. We tried to limit the sites to those with minimal advertising and offers to sell stuff, but the internet is now a commercial tool so buyer beware.

http://www.kodak.com and go to consumer photography and taking great pictures. This site has pretty basic stuff but it’s well done.

http://www.photo.net/learn Covers film and digital with some interesting stuff on toning.

http://www.lexar.com/dp/tips_lessons/index.html This commercial site has lots of good stuff in lesson by lesson format.

http://www.shortcourses.com Good stuff but embedded sales links

http://www.luminous-landscape.com/tutorials/ A wealth of information with links to all kinds of stuff.

http://www.nyip.com/ Get past the ads and go to the reference shelf

http://www.shutterbug.com/techniqueslp/ Like most magazine sites, this provides access to a lot of past issue articles.

PANORAMAS MADE EASY
By Andy Long

When we look at the world around us, we see things more or less in a panoramic perspective. Our peripheral vision is pretty mucxh 180 degrees. Our photographs, on the other hand, capture just a small portion of what we actually see in front of us. Many times we want to zoom in tight to capture just a small part, but there might be a time when getting everying in front of you captures the true essence of the scene.

Maybe you've hiked out to Delicate Arch for a sunset shot but when you've looked at the image it wasn't quite what it was when you were there. Maybe you've had a beautiful fall color scene in front of you with mountains spreading across from left to right and lots of beautiful color in the foreground. To capture it fully, the best way to do this is by taking a panorama of the whole scene.

In days gone by, special cameras would be needed. Or, lots of time in the darkroom to bea able to create the image you want. With digital, though, it's a lot easier to create a panorama of whatever scene you want and quite easily at that.

The first step is the taking of the photograph, or to be precise, taking a series of photographs. To do this it's best to use a larger lens, something in the range of 100mm to 200mm and shoot a series of vertical images. By shooting vertical and using more images, you get greater detail in each of the shots as opposed to just two or three horizontals.

You have to have a bit of an overlap between each shot. I usually try to have at least a 20% overlap and you can go up to 33% or more. You don't have to be exact with each shot because the software you use will be able to match the overlaps. What you do want to try and get as close to exact as possible is your horizon line. This is where your level on your tripod head comes in handy.

Take at least five images to create your panorama. The more you hvae the larger your image as well as the file size. I've found that 5 or 6 seem to work best for getting everything in the shot that's in front of you.

Do not use special filters, especially a polarizer as they will cause differences in the tonality of the sky, which will be quite evident in your final image. If you use a zoom lens for the series of shots, keep it at the same focal length throughout otherwise you won't have a good match. You also want to keep the same exposure settings for each image. Do a test of the different values in the shot and set a good compromise manually. Do not move the tripod once it's set in position. Just rotate the head to create the series.

What to use to create your panorama once the shots have been taken? Photoshop CS2 has a function in it that will create a panorame for you called Photomerge. It's access by doing File > Automate > Photomerge. While this works nicely, a program like Panorama Factory I feel does a much better job. It's pretty straight forward in how it works and walks you through a serices of several steps to create a seamless stitched image. You can go to www.panoramafactory.com and downlaod a sample version of it or buy it for $69.95. It's a fun program to play with and you can create some very interesting shots with it.

The following shot was taken with 5 images and processed with Panorama Factory.

COLOR MANAGEMENT
By Bob Dean

Digital photography has added a lot of new “buzz words” to our vocabulary. One of the most misused or perhaps least understood is “color management”. Discussions of color management lead to more terms like color space, rendering, sRGB, and so forth. We figured a brief foray into the realities of digital color is warranted, so we can utilize the new tools we have.

What does color management mean? Essentially it’s the catch-all term that describes the process of making sure the colors of your subject are displayed the way you want them on the medium of your choosing, and that you can achieve that result consistently! First let’s define a few terms:

Color space is the portion of the color spectrum that is available to the output device (monitor, printer, etc.) for display of the image. In other words, how many colors can you hope to reproduce.

Rendering is the software process of converting a RAW image into a usable file in a specific color space. This word comes from rendition. Another techie convolution of the language.

Color space -. The first step in color management is determining the color space in which you want to work. Remember that RAW files are “rendered” to the color space by the camera’s internal software or the post processing software in your computer. If you shoot only RAW, the rendering must be done in the post processing on your computer. If you can select multiple output files such a RAW plus jpeg, you can specify the color space for the jpeg files.

You should select your color space based on the planned use of the image. Most digital cameras will allow you to select Adobe RGB or sRGB. Adobe RGB has a slightly larger gamut of colors and is less saturated than sRGB. Adobe is more closely correlated with ink jet printers. If you are more interested in viewing your images on a monitor or projecting them with an LCD projector, the slightly smaller color gamut and more saturated sRGB color space is better. Post processing programs also allow CMYK color space which is more suited to publication formats. It’s possible to create different files from the same RAW image in various color spaces using the computer’s RAW conversion program (Photoshop™ as an example).

Calibration of your computer’s monitor - What is calibration and why calibrate? This reason is very simple; it allows you to get prints out of your printer that look just like to image you saw on your monitor screen. OK, what if you don’t print your images but send them out to others for printing, use in magazines, contests, and so forth? Calibration has been compared to such mundane things as getting your car aligned or flossing your teeth, not required but very good practice. When you send a digital file out for any purpose, you really don’t know if the next person down the line will do proper color management. If you know you sent out the best file possible, then the next user will start with a superior product and you’ll have a much greater probability that your image will stand out.

There has been a lot of talk about LCD monitors not being very good for calibration since they drift quite a bit over time and temperature; this was true a few years back newer models are much better and can be calibrated as good as the old CRT models.

The first step in calibration is looking at the monitor. There are whole books written on this subject. In order to calibrate your monitor, you might consider the purchase a calibration product that includes software and a sensor. Many of these packages are available priced from under $100 to several hundred. A little bit of research on the internet will allow you to pick the right one for you. There are also more manual tools, some free, that allow a degree of calibration using the computer’s internal tools and specific light sources.

A really good website with lots of links to information, manufacturer’s sites and a good starting point for monitor calibration is: http://www.normankoren.com/makingfineprints1A.html

Take a look at this site and get started doing better color management of your images!

METERING MODES
By Bob Dean

We have all heard the comment, “well I just fix it in Photoshop™”. I’m not too sure about you but I would rather spend my time in the field shooting than in front of the computer fixing images. One of the best pieces of advice I ever heard, whether shooting film of digital is “get the exposure correct when you take the picture”. If you do this, you will not need to “fix” it later. Over the next few months, the digital corner will go back to exposure and metering basics. This month we’ll look at the metering modes available in today’s digital SLR camera bodies.

Most digital SLR’s have followed their film predecessors in having a variety of metering modes. The 3 basic ones are matrix or pattern, center weighted and spot. In the case of my Canon 40D, the engineers have added a 4th they call “partial”. This forth one is really a variation on the spot meter capability.

The “meter” in the camera is really a combination of the light sensors and the computer’s microprocessor. The processor takes input from the sensors and computes the exposure based on the sensor light readings, the aperture setting, shutter speed, focal length, and a lot of data stored in “look up tables”. Let’s look at each of selectable metering modes of the sensor and consider how to use them most effectively.

Matrix or pattern looks at the entire image divided into a number of segments. In the case of the Canon 40D, there are 35 segments or zones evaluated. Here is an example of the zones in a simpler, 13 segment matrix pattern:

As you can see, the zones are not uniform, but are designed to give the camera’s processor information according to a “best case” for normal compositions. Normal is defined as average distribution of light, medium and dark tones. Matrix is usually good for front lit scenes, or scenes with minimal contrast or a moderate mix of light and dark tones.

Center weighted and partial modes look at the entire scene but give substantially more “weight” to the center. Typically 70% of the information from the center area and 30% from the periphery are used to calculate exposure. Here is an example of the center weighting approach.

Center weighted exposure is probably one of the better tools we have. This mode uses a lot of the experience developed over the years of film shooting. Center weighting, along with the exposure lock feature on the camera, provides a very good tool for getting the best exposure possible. This mode is best for scenes with highly directional light, a scene with very bright sections and very dark sections, like a landscape with bright sky and dark foreground, and high contrast scenes. To most effectively use center weighting, while controlling over exposure, always include the brightest area in the center (biasing toward the highlights). Take the reading in manual or any of the creative exposure modes (shutter or aperture priority) and lock the exposure with the AE lock. Then recompose and shoot! A word of caution, this mode, like any other, averages to middle grey so you may need to compensate for very white or very black subject matter.

Spot and partial metering looks at a small part in the center of the frame. All exposure information is calculated from that area. This metering mode is very good for subjects that are in shadow, where you need to control or saturate highlights, and high contrast scenes.

Spot metering also averages to middle grey so you may need to compensate or look to use white balance to get a correct color rendition.

Next time you’re out shooting, try these different metering modes, consider the lighting of the scene and take a few notes on which mode you selected for each shot. Consider adding some comments on why you chose that mode, and see how your images come out. Do this a few times and maybe you’ll spend less time in front of the computer and more behind the lens!

CALIBRATING YOUR PRINTING PROCESS
By Bob Dean

Ever wonder why your prints don’t always look like what is on your display? Why do we need to calibrate our equipment to get the color renditions we want? This month we take a look at the whys and the hows of getting better color prints at home on your existing equipment.

To start with, the processes used by the various pieces of equipment in personal computers differ in the way they handle color reproduction. To begin with let’s look at monitors and printers. This doesn’t even consider scanners! Monitors use an additive RGB (Red-Green-Blue) process to reproduce color. Red, green and blue when added together will produce black. The printing process on the other hand uses the subtractive CMYK (Cyan, Magenta, Yellow and Key (Black)) process. Don’t worry about the additive and subtractive terms; they refer to how light waves interact with your visual system.

To get your color printing to match what is on the screen, you need to calibrate both your monitor and your printer. There are a myriad of ways to do both but the real key is to calibrate your monitor before your printer. You can calibrate your monitor visually or mechanically, depending on critical you are with the color prints you’re making. I found a few websites that have links to some really valuable tools for visual calibration. If these work for you, great, if not you will need to invest in some of the hardware/software products available for monitor calibration. I suggest you look at this website to start with visual calibration:

http://desktoppub.about.com/cs/colorcalibration/a/cal_monitor.htm

This site some has introductory text and links to some pretty good tools. It also has links to similar sites for printer and scanner calibration. Be warned, once you start on the process it can be captivating. Remember the goal is to get printed images you like, not the absolute maximum calibration settings of your equipment.

MEGAPIXELS AND IMAGE QUALITY
By Bob Dean

The larger the number of mega pixels, the better the image right? After all, when we all learned the basics of photography we learned a few axioms. Lens quality was number one and then film grain which we could relate to ISO film speed. Well, welcome to world of high tech. The number of pixels in a camera's sensor is not a good indication of the ultimate image quality, nor is the lens quality. The design engineers have added something a whole lot more difficult to measure with a simple number. What is it? Software!

Pixels are small light sensitive elements that convert light (photons actually) into electricity (electrons). A series of filters on top of the sensor determines the basic color information and then some electronic circuitry near the light sensitive areas of each pixel amplify the signal and send it on to the micro computer chip. There are some nasty characteristics of the electronic devices that convert light to electricity. First, the smaller the pixel, the less efficient they are, meaning it takes more photons to generate a given amount of electrons. This means smaller pixels don't work as well in low light as do larger ones. Also the amount of surface area that gathers lig! ht is reduced because space is needed for the electronic circuits that amplify the signal. Worse yet, small pixels tend to generate more noise proportionally than larger ones.

This is where we look to the software. Each camera manufacturer has developed their own image processing software that turns the electrical signals into an image. This software does an amazing amount of work in a very short time. Among other things, it has noise reduction algorithms, routines that integrate the signals according to color and the capability to smooth out the edges of pixels. Only a few companies make sensors and signal processing chips, but each major camera company has its own proprietary software. Not only that, but even in one company software can vary between camera models. The most important capability of the so! ftware is the noise reduction, as it is the most difficult thing to do well.

How does this impact the camera buyer? Well, when you are looking at point and shoot digital cameras, don't just go for the 5-6 MP. A 4 MP may give you a better image. Research the web and the magazine rack to get reports on image quality before buying. Also, the sensor pixels in digital SLR's tend to be bigger so the impact of noise is reduced and the image quality improved by most all camera company software.

SENSOR SIZE AND MAGNIFICATION
By Bob Dean

This month we'd like to address two of the things a lot of photographers fairly new to digital photography find perplexing. First, why do digital cameras give an apparent magnification and what are the tradeoffs? The apparent magnification of a digital camera starts with the relative size difference between 35 mm film and the electronic sensor used for digital image capture: "35 mm" film has an effective image size of 24 mm high and 36 mm wide for a "horizontal" image. When we photograph something through a lens, we record a certain size image of the subject on the film.

Digital cameras have sensors that vary in size, and except for a few very high end cameras, the sensor is smaller than the 35 mm image size. In the case of the Canon EOS 20D, the sensor is 15 mm high and 22.5 mm wide. If you do a quick calculation you'll see that the dimensions of the 35 mm image are 1.6 times bigger then the digital sensor.

If we assume the same conditions when we photograph the same subject, that is camera to subject distance and focal length of the lens, the image on the digital sensor will be the same size as the image on the film plane. That's just standard photographic optics. But remember the size of the sensor is smaller than the 35 mm film frame.

Now the real impact of digital! The software in the camera enlarges the image to give an equivalent 35 mm image size.

In doing so, this software magnifies the image on the sensor by the same amount that is needed to make the image sensor look like the 35 mm image, in our example of the Canon EOS 20D, this is 1.6x.

OK, we now have a l.6x magnification, what did it cost? If we had used a 1.6 teleconverter we'd have lost some of the image because the angle of view would have been decreased as the effective focal length of the lens increased, the same happens with the digital, but in this case, the information that the lens gathered was focused beyond the edges of the sensor so it was lost; the same effect as reduced angle of view. The second thing we lose with a teleconverter is light, namely the effective f stop of the lens is increased by about 1 stop. (f4 to f5.6 for example) In the case of a digital camera, this is not the case. The camera will still show the f stop as the same. BUT, the resolution of the sensor (number of pixels per unit of area) is fixed so a slight increase in what is equivalent to grain will be seen. Digital camera noise reduction software does a very good job of smoothing out this grain effect, so the apparent magnification gained is pretty close to free.

Now let's think about a few other things that may have slipped by in our discussion. First is the aspect ratio. That's a fancy mathematical term for the relative size of the horizontal and vertical dimensions. 24 x 36 or 15 x 22.5 have the same ratio, 2 to 3. This has a real impact in printed image size and can readily explain the popularity of printing image in 8 x 12 size instead of the venerable 8 by 10. 8 by 12 does not require cropping of one dimension. When digital scanning and printing became popular, the long held 8 by 10 dimension was challenged and quickly abandoned.

The second thing to think about is some of the new lenses being marketed. If you look at the magazine adds for some new products, such as Canon EF-S lenses, you'll see a note indicating these lenses are only for digital cameras like the 20D. This is because they focus the image not to a full 24 by 36 mm area but to the size of the image sensor. Remember we said earlier that the equivalent of reduced angle of view was due to the information falling off of the edge of the sensor? This doesn't happen with these new lenses. The effect if these lenses were used with a film camera body, assuming the computer in the camera would allow the photo to be taken, would be a smaller image on the film plane.

WHITE BALANCE
By Bob Dean

As we all look to migrating to the world of digital photography, we need to be prepared to learn new terms and new ways of applying the tools of this medium to image capture. Digital has brought with it a whole new set of terms that can be daunting. The other day I was in a discussion on one of these, white balance, and it became clear that this is a scary topic for a lot of people. I wanted to take this opportunity to address white balance for those of you who have questions about what it is and to address how to use it creatively.

To understand white balance, we need to look at an old friend and some basic human vision processes. First let's consider color temperature. This concept has always been part of film photography as we have used special films, flash units etc. Color temperature refers to the color of light. The concept is one we have borrowed from the world of physics and of course we have applied our own photo-related spin to it. Color temperature is the value assigned to the color of light that radiates from a theoretical object physicists call a black body. As the temperature is raised, this body starts to glow, first a dull red, then brighter red and finally a blue-white. Since it's a theoretical object, melting is not a concern. Color temperature is measured in degrees Kelvin. This is a temperature scale that is the same as the Celsius (or Centigrade) scale except it is offset so that 0 degrees Kelvin is the same as about -273 degrees C. (This value is referred to as absolute zero, the coldest temperature that can exist in nature.) In nature we have low color temperature (red) moving up to high color temperature (blue). As photographers, we look at this in the opposite way, red being warm and blue being cool but so what!

Now let's look at human vision and how a digital sensor tries to emulate it. The human eye has two types of light sensitive organs in the retina. One type is called a rod. The rods are special organs used to provide vision in very low light and do not differentiate color. The other organ is called a cone. The eye has three types of cones. These cones detect can red, blue and green. The optic nerve conveys information from all of these sensors to the brain where the information is processed to give us vision. The designers of the sensors in digital cameras (whether CCD and CMOS) have taken the structure of the human eye and emulated it in the camera. The sensor elements or pixels are arranged so that they detect light and produce a signal that represents the amount of light energy striking the surface. In order to produce color, a series of red, blue and green filters are used in front of the sensor. This very closely emulates the concept in the human eye. This information is passed to the camera's "brain" where a software program assembles it into an image. This is where the analogy starts to break down. In the human brain we use experience to recalibrate the image we see. For example, when we read characters on a sheet of paper, the paper is white regardless of the color temperature of the light illuminating it. Just try reading a book under fluorescent lights, outside in the evening, or with incandescent lights. In each case the page appears white.

The digital camera tries to emulate the brain by setting a white reference or balance. To do this, it must be calibrated to what is truly white. Most cameras have three white balance settings. With auto white balance, the camera assumes that the scene has significant white content or more correctly, has a "normal" ratio of blue and red. The second setting is a preset white balance where the camera allows the photographer to choose a white balance based on evaluating the scene. This is similar to choosing a special film or a compensating filter to adjust for the color temperature of the light source (tungsten film, fluorescent light filters, etc.). The third white balance option is manual and represents the best creative tool. Manual white balance allows the photographer to set the white balance for the actual situation. Using a white card to allow the camera to establish the correct baseline for the conditions can do this. (Hint: Sometimes a white card can be overexposed, so when you use it, draw a black line on the card and verify the exposure by checking the image on the LCD screen. Use a felt pen and draw a line on the card. Take a shot and verify that the image on the LCD screen is properly exposed, showing the line accurately.)

The manual white balance sets the camera for "normal" conditions but it can be used creatively as well. By using a light blue card instead of a white one, you can achieve a warm tone to the image, similar to adding an 81 series filter to the camera. If you wish to cool the image, calibrate the white balance with a light pink card. There are several companies that make cards for this use. They have been around for quite a while supporting the television and film industries. One is www.warmcards.com. Also, since you're not burning film, you can experiment!

There is a tendency to set white balance to auto with the idea that you can compensate with the computer later. By all means fight this impulse! White balance is a very non-linear process, treating red, blue and green differently. When you use your computer, it will change the effective color temperature of the image uniformly across the image and not give you the same color rendition as if you properly calibrated the white balance.

COLOR MANAGEMENT PART 2 - CALIBRATION
By Bob Dean

Last month we discussed color space and how to select it based on the desired use of the image. This month we’ll look into calibration of your computer’s monitor.

What is calibration and why calibrate? This reason is very simple; it allows you to get prints out of your printer that look just like to image you saw on your monitor screen. OK, what if you don’t print your images but send them out to others for printing, use in magazines, contests, and so forth? Calibration has been compared to such mundane things as getting your car aligned or flossing your teeth, not required but very good practice. When you send a digital file out for any purpose, you really don’t know if the next person down the line will do proper color management. If you know you sent out the best file possible, then the next user will start with a superior product and you’ll have a much greater probability that your image will stand out.

There has been a lot of talk about LCD monitors not being very good for calibration since they drift quite a bit over time and temperature; this was true a few years back newer models are much better and can be calibrated as good as the old CRT models.

The first step in calibration is looking at the monitor. There are whole books written on this subject. In order to calibrate your monitor, you might consider the purchase a calibration product that includes software and a sensor. Many of these packages are available priced from under $100 to several hundred. A little bit of research on the internet will allow you to pick the right one for you. There are also more manual tools, some free, that allow a degree of calibration using the computer’s internal tools and specific light sources.

A really good website with lots of links to information, manufacturer’s sites and a good starting point for monitor calibration is:

http://www.normankoren.com/makingfineprints1A.html

Take a look at this site and get started doing better color management of your images!

SAVING YOUR DIGITAL IMAGES
By Bob Dean

Now that you have that new digital camera and are starting to amass a large quantity of images, where do you plan to store them? When we were all shooting slides, they went into plastic pages and then into three ring binders (unless they stayed in boxes with illegible notes written in on the side (I've got lots of those). Now the world has changed and your images are nothing more than a large number of 1's and 0's on some form of storage medium. There are a large number of possible long-term storage methods, each with pros and cons.

Most cameras use Compact Flash (CF) memory cards to record as you shoot. It's possible just to keep buying those cards, especially if you only store jpeg files. 1-gigabyte (GB) cards are down to the $100 range and getting cheaper. A 1 GB card can store several hundred jpeg images from a 4-6 mega pixel camera. That's still pretty pricey and the there is not a lot of room to write information on the card itself. Beware that CF cards are VOLATILE, meaning they be easily erased.

Let's assume you make the choice to down load your images to your PC (or Macintosh system). You now have many more choices for long term storage (notice I did not use the word permanent!). It's possible to add large hard disks to your system (either internal if you are comfortable taking your system apart) or external. External drives connect by either serial or USB (Universal Serial Bus). Hard drives hold lots of data, hundreds of gigabytes in some cases. These are somewhat expensive but you have the luxury of having your images on line and at your fingertips. On the down side, these things are mechanical and wear out, sometimes without warning and if your drive crashes, you may lose every bit of data on the drive.

There are also on-line storage services that allow you to store data at very low cost, sometimes at no cost. These are great as you can access your images from any computer on the internet, using a password. My only caution here is that no one can predict how long these service providers will be around and how much notice, if any, will be given if they do go out of business.

Most people store images on CD's or DVD's that they burn directly from their PC. These are flexible, very inexpensive and allow for many images to be stored in a very small space. So what's the drawback here? The recording method is called burning for a reason. If you record to a CD R or a DVD R (as opposed to one with an R/W) you are using what's known as an ablative process where a tiny laser actual burns marks in the surface of the disc. These marks aren't permanent; corrosion can start soon after recording and eventually make parts of the data unreadable. The current technology for write-once CD and DVD products will support a usable life of about 10 years for HIGH QUALITY discs. Don't use the very cheap discs, as their lifetime is a gamble; buy the best you can get. If you use R/W or rewritable CD's or DVD's you are using a similar process to record data as is used in hard disks, namely one with that is magnetic. These discs are not the best for long-term storage as they can suffer the same fate as magnetic material and can degrade over time (lose parts of the image).

So, just like every other facet of photography, storage of digital images is a handful of tradeoffs between price and ease of access, longevity, etc. The nice part is that you can easily make multiple, identical copies of your images with no degradation and if you can re-record data, again with no image degradation.

My recommended approach is to use high quality CD's or DVD's and note on each one's case when you recorded the data. Then every few years copy the data on to a new disc. As technology moves forward, new, better and more permanent products will become available.

IMAGE STABILIZATION
By Bob Dean

Several camera and lens manufacturers offer features on cameras or lenses that compensate for camera shake or movement. The methods do vary from one manufacturer to another.

The most common, and probably the most successful method, is the use of sensors within the lens. These are known as Image Stabilization (Canon), Vibration Reduction (Nikon), and Optical Stabilizer (Sigma). Within the lens is a set of sensors that detect small movement and correct for it by moving a small optical element in the opposite direction of the shake or movement.

Other companies (such as Konica Minolta) employ a similar function in the camera body and move a prism that is located between the lens and the image sensor.

Video cameras use a digital method where the image is retrieved from different pixels on the sensor to compensate for vibration or camera movement. That works well in the video arena but has significant image blurring in still work.

The movement compensation feature was originally designed to allow slower shutter speeds while hand holding the camera and still produce sharp images. Typical claims are an apparent increase of two to three stops.

Use of this technology is not without drawbacks. There is an added weight and cost factor for the lens based approach. The in camera version also adds cost to the body but does allow use of many more lenses.

When using the stabilization capability on a tripod, there is a potential problem. If the camera and lens are very stable, the electronic circuits in the lens may become slightly unstable and cause the image to blur a small amount. Some lenses have tripod sensors and correct for this. Others have a recommendation in the manual suggesting that the feature be turned off when the lens is on a tripod. As with all photographic “rules” there is a lot of controversy about this. The stabilization feature can compensate for movement and for vibration induced by tripping the shutter at slow speeds. Even when mounted on a tripod, the ability to reduce apparent shutter vibration can be a valuable tool.

The best approach is to do some research before buying or do some testing if you already own one of these lenses or cameras.

Is the feature worth the money and extra weight? In our opinion, YES. We have a 100-400 IS zoom from Canon and love it. Everyone we have talked with has a similar feeling about that particular lens. We’d be happy to publish accounts (positive and negative) concerning member’s experiences with this or any other stabilized lens.

WHITE BALANCE AND COLOR TEMPERATURE
By Bob Dean

This month, as promised, we’ll look at white balance and color temperature. Most high end point and shoot and virtually all digital SLR’s have provisions for selecting white balance and color temperature. What this means is pretty simple. The photographer can select the camera’s method of representing color on the recorded image.

White balance is simply the camera’s way of looking at all colors of the spectrum and generating true white. The basic setting is AWB or auto white balance. In this mode the camera looks at the entire scene, assumes the light is about midday and comes to a conclusion as to what white should look like. The most creative white balance control is the custom one. Depending on your camera (check the manual) you can find a white object and use it to set the white balance so the camera can accurately record white in the light that’s available. You can also use other neutral colors to cause a shift in white balance but be careful; you can get some “interesting” and perhaps not too pleasant results.

If you really want to be able to alter a scene however, try the color temperature adjustment on your camera. Light is measured in “color temperature” and there is a relation between this value and warmth or coolness of the light. It’s a little confusing but the lower the color temperature, the warmer the light. This is a collision between science and art. Some examples are:

Candle light 1500, Incandescent light bulbs about 3000, morning and evening light is between 3400 and 4000, midday is 5000 to 5500. Flash is typically between 6000 and 6800 while a heavy overcast generates 6000 to 7500. Check out the final paragraph of this article for more details.

There are two ways to compensate for color temperature. One is the post processing phase (on the computer with an image processing software tool) and the other is in the camera. Anything you can do in the camera is inherently better because you are not disturbing the digital image through recompression and manipulation. It does take some experimenting to use color temperature corrections but consider this tips:

To warm up a scene, adjust the color temperature to a high (cooler) value. This is not as confusing as it first appears. The color temperature adjustment on the camera tells the software what color the light is on the subject. If you tell the camera that the light is very cool (high color temperature) the processor will “warm it up” to come to the midday neutral color. If you’re shooting at midday, try setting the color temp to 6500 if your camera uses degrees or to the “overcast” setting if it uses verbal settings. In both cases the camera will warm up the scene.

Don’t rely on the LCD screen on the camera to give you instant feedback on color. These little screens are great for checking to see if you recorded the image, if the exposure was relatively OK and if your composition was close to what you wanted. They are not good for checking color, focus or details of the image. You don’t see those until you view the image on a calibrated monitor or properly produced print.

Using color temperature creatively requires the old fashioned concept of taking notes and then reviewing the final images. From this you can start to learn how to most effectively use this creative control.

By the way, for those of you interested in how color temperature measurements are determined, here is a brief physics lesson. In you were to take an object physicists call a black body and heat it until it started to glow, the color of the object will be related to how hot it is. The lower temperatures will generate a warm orange glow that will become whiter as the temperature increases. The temperature is measured on a scale known as the Kelvin scale. This is similar to our friendly Fahrenheit scale but is shifted so that 0 degrees Kelvin is the theoretical absolute zero.