I have noticed in lots of RAW image converter programs that if you assign 2800 degrees Kelvin to any normally color balanced picture it becomes blue, whereas per our info 2650K is for household lamps, and when you assign 10000K, the image becomes yellow. Will you please explain what is the logic behind this method...Anyway thanks for your fantastic column and let me also congratulate Canon for serving the photographic community so well and for so many years...

Thanks for the kind words! When you dial in a color temperature value on your digital SLR, you are telling the camera what's neutral for the lighting conditions at hand. Therefore, if the actual color temperature of the scene is higher than the dialed-in value, the resulting image will have a cooler white balance, and vice versa. Think of it this way: If you had a color film that was balanced for tungsten illumination, and you shot a photo without a filter in daylight or with flash, the resulting image would be very blue in tone because the color temperature of the scene was much higher than the color temperature rating of the film. Or, in your example, if you dialed in 10,000K but the actual color temperature of the scene was only 2,650K, the resulting image would be very warm or yellow because the scene is warmer than the color temperature you selected.

I am getting acquainted with my new Canon EOS-1Ds Mark II, but have encountered one technical problem. On my PC running Windows XP, my camera is recognized by the Windows Scanner and Camera Wizard, by ACDSee Pro, and by Photoshop CS2. It is, however, NOT recognized by the EOS Viewer Utility V.1.2.1 or by Digital Photo Professional. I've read all the reference books and played with all the possible adjustments, but can't understand this. Also, the personal functions can only be set with the viewer utility, not in camera, so I am unable to accomplish this.

EOS Viewer Utility 1.2.1 must be paired with EOS Capture 1.5 in order to support the EOS-1Ds Mark II for tethered shooting, but both of these applications have been replaced by the combination of EOS Utility 1.0 and ZoomBrowser EX 5.6 and/or Digital Photo Professional 2.1 on the Windows platform. You can't mix and match the older software with the newer applications. (I'm not saying you did, but you haven't provided enough information to rule it out.)

The fact that your other applications are recognizing your camera gives me hope that your WIA driver installation is not corrupted, but as a last resort it may be necessary to uninstall and reinstall the WIA driver on your system. Before you take that step, I would suggest that you install EOS Utility 1.0 together with ZoomBrowser EX 5.6 and/or Digital Photo Professional 2.1. If tethered shooting is important for you, you'll be happier with DPP 2.1 because it can be set to display a larger image. Here are some tips:

1. Before connecting the camera, launch EOS Utility and set up your Preferences. In "basic settings," be sure to check the box that automatically launches EOS Utility when a camera is connected, and decide whether you want to have the program display the remote shooting screen immediately. Other items to set include the choices for "linked software" and "destination folder." You can also set up file naming and numbering at this time.

2. If you decide to link EOS Utility to DPP, launch DPP and set its Preferences. Locate the bottom of the General Settings tab and decide if you want to have DPP display the Edit image window during remote shooting with EOS Utility. If you do, you'll get a much larger image that refreshes each time you capture a new photo.

3. Once the Preferences are set for both programs, close them and connect the camera. This will automatically launch EOS Utility and get you into the Remote Shooting screen. Use EOS Utility's Preferences window to switch destination folders as you see fit.

Instruction manuals for EOS Utility, ZoomBrowser EX 5.6 and DPP 2.1 are available on our Web site when you download the software. Be sure to have EOS Viewer Utility installed on your system before you begin, because the downloads are updater versions that look for an eligible installed application prior to installation.

Hope this helps! If you need further assistance, I would suggest contacting our Customer Support Center at 1-800-828-4040.

I have a Gossen light meter that I use on occasion but I'm sure that I'm NOT using it to the fullest of its abilities, especially regarding the determination of highlight/shadow ratios, etc. Can you provide any links to discussions or articles that give details on just what can REALLY be accomplished with a decent light meter beyond the trite "x" aperture at "y" shutter?

Here are a few online resources that should be helpful to you:

http://www.danheller.com/tech-metering.html

http://www.photozone.de/4Technique/metering.htm

http://www.kodak.com/cluster/global/en/consumer/products/techInfo/af9/index.shtml

In addition to these articles, you can also tap into the expertise of many experienced photographers by joining or searching through an online forum, such as:

http://www.photo.net/

http://www.openphotographyforums.com/

There are many other resources, including Jim Zuckerman's book entitled "Perfect Exposure," which may be available through your local public library or bookstore. Thanks for reading Tech Tips!

I recently upgraded from a Digital Rebel XT to the EOS 5D. My general purpose lens is an EF24-70mm f/2.8L USM which is a good range on the XT with 1.6x crop factor, but a little short for the 5D at full frame. It looks like the new Canon EF24-105mm f/4L IS would be Canon's best offering, but I don't understand the logic of IS over a faster lens. Is it possible for Canon to make an EF24-105mm f/2.8L? The advantage of IS is that you can shoot at slower shutter speeds, but that isn't usually optimal since subjects move.

Increasing the maximum aperture of a professional-quality 24-105mm zoom lens from f/4 to f/2.8 would increase the size, weight and cost of such a lens substantially. The Image Stabilizer function of the EF24-105mm f/4L IS USM helps to mitigate those factors by allowing hand-held photography up to three full shutter speed steps lower than the nominal hand-held limit of 1/focal length. It's not a perfect solution, but it's arguably more practical than a 24-105/2.8 zoom lens for many photographers, in terms of budget as well as portability and ease of use.

In the July issue of Tech Tips you posted the following letter from someone:

"I recently had an assignment that required me to photograph at 1600 ISO using my Canon EOS-1Ds Mark II and EOS-1D Mark II N. I had to photograph a dance performance and stop motion on a low-lit set. At 1600, my exposures ranged from 1/250 to 1/500 at f/2.8. The problem I encountered was that in the black shadow area when I blew up the images I saw a number of blue dots. I tried using Noise Ninja to correct the problem but it only made it worse. Can you tell me what caused this and is there a solution to the problem?"

You answered saying that it was probably "noise"; however, I have run into the same issue with my 1D Mark II during high ISO (800-3200) in low-light situations and through my research have concluded these are "hot pixels" caused from charged pixels on the sensor. This does not always happen and was most pronounced during one wedding I shot last September. Since it has not happened since I am left to wondering what on earth caused it for this particular shoot. Are hot pixels something that Canon repair can address if I send the body in?

Thanks for bringing that up! Hot pixels are definitely another possibility for this phenomenon. They can be caused by any number of things, including, believe it or not, cosmic particles emitted by the sun. They tend to show up more frequently in time exposures, and they are more visible in dark areas of an image. There is really no way to prevent them from happening, but there are several ways to keep them out of your processed images. One of the best ways I've found is to use the 'Copy Stamp' function of Canon's Digital Photo Professional (DPP) software. This is essentially a cloning technique, but it's very powerful because it can be applied to multiple images very quickly.

Got the 5D and love it. Question: Long exposure noise reduction. Is there any reason to ever turn this off? It's an option so there's got to be a reason but you got me! Also, I assume this does not affect RAW files?

For most EOS 5D users, it makes sense to leave the camera's long exposure noise reduction function turned on all the time. The main reason why we offer the ability to turn this feature off has to do with the amount of time it can take for the camera to process the noise reduction algorithm between frames. Fortunately, this only becomes a factor at ISO 1600 and 3200, which are sensitivity settings that many users would never select for time exposures. However, when the 5D is set for these ISO speeds and the long exposure noise reduction function is on, the camera requires an interval equal in length to the original exposure in order to process the noise reduction data for exposures lasting 1 second or longer. Turning off long exposure noise reduction under these conditions allows the photographer to eliminate the delay between frames that would ordinarily occur.

I shoot with an EOS 20D and an EOS 5D. The 20D is set to Parameter 2. Which picture style setting do I set so that the 5D images look the same as the 20D? I have noticed in my outdoor portraits with the 5D I get excessive green tones in the shadow areas that I don't get with the 20D. Any advice would be greatly appreciated.

The closest match for the EOS 20D's Parameter 2 on the EOS 5D would be the "Neutral" Picture Style.

Thanks for reading Tech Tips! That's it for now. See you in September!

You are invited to submit questions about photo equipment, imaging technology, or photo industry trends that may have a bearing on your work or interests. I cannot promise to answer everything, but I pledge to do my best to address the issues that concern you. (Please use the e-mail link provided at the end of this article.)