I cannot get my computers to communicate with my EOS-1D Mark II N. I have tried two different PC notebooks with Windows XP and Windows 2000 and with all the correct drivers (and programs) installed but still I am unable to get connected and talk with the camera or download images straight from camera to the notebooks. Any help?

There's not enough information here for me to provide a definitive solution, but based on your description, here are a few suggestions:

1. As a first step, be sure to use a genuine Canon interface cable. As I mentioned in an earlier Tech Tips column, some of the generic IEEE1394 cables and plug adapters on the market have proven to be unreliable for use with EOS Digital SLRs. If your notebook computer has a 4-pin plug (same as the camera's), you might have to purchase an optional Canon IFC-200D44 or IFC-450D44 4-to-4 pin cable. They're basically the same, except for length. The IFC-200D44 is 2 meters long, while the IFC-450D44 is 4.5 meters long.

2. For your Windows XP computer, make sure to install the correct WIA driver for the 1D Mark II N. Currently, we're recommending Version 5.8, which is available for download through our Web site here:

http://www.usa.canon.com/consumer...

2A. On Windows 2000, you'll need TWAIN driver 5.8 instead, which is available from the same Web site as mentioned above.

3. After installing the correct driver, connect your EOS-1D Mark II N with a compatible interface cable and check the LCD data panel to verify whether the camera is communicating with the computer. You should see the connection icon on the back of the camera in the lower right corner of the LCD data panel below the LCD color monitor.

If you don't see the connection icon, it might be necessary to have the computer checked out by a technician to determine if its IEEE1394 interface is working correctly.

I own a Canon Rebel XTi. I was wondering with the sensor cleaning mechanism at shutdown whether it is better to shut off the camera during short pauses when taking pictures or to let the camera go into 'sleep' mode.

As a matter of "best practice," it's a good idea to run the XTi's Self Cleaning Sensor Unit after changing a lens, but there is no need to shut the camera off during short pauses between shots. For most situations, I would recommend simply letting the camera go to sleep to conserve battery power if the interval between shots exceeds the default 1 minute Auto Power Off setting.

Your tips are always great here, on Digital Wedding Forum, and other sites. I was wondering if Canon has a statement on storing batteries in Compact Battery Pack CP-E3 when not in use. Do the batteries drain faster in the unit or is it the same as a normal drain of a NiMH battery in a holder?

Thanks for the kind words! I haven't seen any official statements from Canon that address your question, but in my experience it's always better to remove batteries from a device if it's not going to be used for several weeks. If that's not the issue for you (in other words, you're using your CP-E3 regularly), then I would say leave the batteries in the magazine during storage between assignments. I have not experienced any significant battery drain with the CP-E3, nor have I heard any claims about it from other photographers.

Is there a technical reason why Canon DSLRs have a maximum in-camera exposure duration setting of 30 seconds? If not, could in-camera exposure settings like 45, 60, and 90 seconds be added as additional choices? Alternatively, could the TC80-N3 be enhanced to allow for intervals of less than 1-second (i.e., zero seconds, 1/4 second, or 1/2 second)? This feature would be very helpful for the type of photography I do: http://www.cosmotions.com/index.htm

There is no technical reason that prevents our camera designers from adding shutter speeds up to 90 seconds to an EOS SLR, but historically, the demand for this functionality has been very low. However, from your Web site I can see why this capability would be beneficial for astrophotography. I'll be happy to forward your request to our Product Development Center in the next monthly market feedback report.

I have always wondered about a certain aspect of the auto-white balance function on my Canon EOS 20D (or any camera for that matter): I often see people refer to a lens as being cool or warm. While I can understand that the lens may introduce a slight color shift, does this have any practical significance with a digital camera? I would think that if you use a gray card to balance the light color, that this would also take out any color shift introduced by a lens, whether working in RAW or JPG (in custom WB). Is there any difference when using Auto White Balance?

A properly adjusted white balance setting essentially mitigates any possible color balance shift that might be induced by a lens on a digital camera. Theoretically, at least, the auto-white balance (AWB) setting on most current cameras has the capability of making such adjustments automatically, However, there are so many variables in terms of individual cameras and individual shooting conditions that it makes more sense to use a custom white balance setting for the conditions at hand, especially if there's enough time to register a CWB reading before taking your photos. AWB should be considered a convenience rather than a precise white balance adjustment method.

This comes up every time digital camera sensor cleaning is discussed: An assertion that the digital sensor carries (at least as long as the camera is switched on) an electrostatic charge that attracts dust. However, I've never seen that stated other than as word of mouth. I have seen some comments that the Digital Rebel XTi has a low-pass filter that has been somehow "treated" to be anti-static. What are the facts about electrostatic charges on sensors and the effect of attracting dust?

I cannot speak for other manufacturers' products, but EOS Digital SLRs with Canon CMOS image sensors do not carry electrostatic charges at any time. Also, when DSLR image sensors are discussed, it's important to remember that the surface of the sensor itself is never exposed to dust. Instead, a low-pass filter is permanently mounted in front of the sensor at a distance of a millimeter or so. The gap between the low-pass filter and the image sensor is hermetically sealed during the manufacturing and assembly process. Once that happens, additional dust particles are prevented from reaching the surface of the sensor. Loose dust particles will eventually end up on the front surface of the low-pass filter during normal use of the camera, such as changing lenses. For this reason, the low-pass filters used in EOS DSLRs are treated with an anti-static coating during the manufacturing process. This coating passively repels dust particles, but at no time is the filter electrically charged in the camera.

Of course, there are many different kinds of dust particles. Most are relatively dry, and small enough that they can be easily dislodged from the surface of a low-pass filter with ultrasonic vibration or a soft puff of air. But others are wet or sticky, and once this type of particle adheres to a low-pass filter, it usually cannot be removed by vibration or air movement. This is the reason why Canon developed the EOS Integrated Cleaning System, which applies Dust Delete Data recorded by the camera to remove residual dust spots in images during post-processing with Digital Photo Professional software in the photographer's computer. It's also possible to clean the low-pass filter manually in order to remove sticky dust particles. Let me know if this answers your questions.

The new Canon EOS-1D Mark III looks to be quite an impressive camera. One question: A friend of mine said someone at a trade show told him the EOS 1D Mk III has a way to determine the focus point of a specific lens. I think he was trying to relay information about the camera selecting the AF points if you set it for that. Is there some feature like what he was referring to on this new camera? I read through all the specs and just think he misunderstood, but wanted to check with you to see if perhaps I missed something.

It's likely that your friend is referring to the EOS-1D Mark III's new AF Microadjustment feature. It doesn't determine the point of focus; it adjusts it. Here's how we describe it in the EOS-1D Mark III White Paper:

AF Microadjustment

AF precision is adjusted for the camera and lens to fall within the lens' maximum aperture's depth of focus. However, there are users who want to adjust it more minutely. They have had to go to a Canon Service Center to have it done. AF microadjustment is a feature developed for these users. Users themselves can now finely adjust the AF focusing position (with a menu setting). The adjustment range is ±20 steps in front of (-) or behind (+) the point of focus.

The adjustment increment of one step differs depending on the maximum aperture of the lens. You should shoot, check the focus, and adjust it. Repeat this procedure to adjust the point of focus. When a lens registered with a point-of-focus adjustment is attached, the point of focus will be automatically shifted by the correction amount set. If you set 1 (Adjust all lenses by the same amount) or 2 (Adjust by lens) and press the INFO button, the adjustment screen will appear. The focus shift amount per step is calculated by multiplying the maximum aperture's single-side depth of focus by 1/8. If 1 is set, the focus shift amount will always be the same number of steps (but the actual amount will vary according to maximum aperture) for all lenses. If 2 is set, the focus shift amount will change for each different lens. You can register the focusing shift amount for up to 20 lenses. Then, when you use one of the registered lenses, the focus will shift by the set amount.

Note that since the camera does not recognize the unique ID of the lens, the same shift amount will be applied to the same lens model even if it has a different serial number. In the case of zoom lenses which have variable maximum apertures, the focus shift amount is technically different at the wide-angle end and telephoto end. However, since the focus shift amount cannot be adjusted individually for the wide and telephoto ends (there is only one shift amount per lens), adjusting it for the telephoto end is better. If an extender can be attached, the camera recognizes whether it is 1.4x or 2x and makes a different shift adjustment from when no extender is attached. When an extender is attached, the adjustment screen will display the lens name and extender name. To delete the registered lens settings, select 1 or 2, then press the Erase button. All the registered AF micro-adjustment settings will be cleared.

You can download the EOS-1D Mark III White Paper PDF here:

http://www.usa.canon.com/templatedata/pressrelease/images/whitepaper/EOS-1D_MarkIII_WP_070223.pdf

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

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.)