Thanks to everyone who submitted questions in September! With no further adieu, here are October's "Tech Tips":

I've been enjoying your new monthly installment on The Digital Journalist and was hoping you could clue me in a bit on the service process at Canon? I've been having focus issues with my Mark II when shooting sports in dimly lit situations where the AF seems to hiccup, so I've been relying on my 1D. I'd like to get this remedied soon though as the Mark II provides much cleaner shots. In searching the message board on SportsShooter it seems that to have the AF recalibrated, they recommend sending both the body and all the lenses into Canon to be recalibrated. Is that correct? And if that's the case, do I also need to send in my 1D to guarantee consistent results? My other question is directly about the service center and how the service progress works. I'm about two hours from the New Jersey center and was wondering if it's possible to set up a time, say a week or two in advance, and get all the service work done in the same day? I'm currently an intern at a daily paper and can't afford to be without my gear for more than a day so sending everything in for service is pretty much out of the question. Thanks much for any insight.

We've produced a PDF document called "Camera Handling and Maximum Image Quality" that covers AF issues for EOS-1 class Digital SLRs.

From page 9: "In AI Servo AF, the camera samples the AF detection data at varying rates of frequency depending on the light level. The brighter it gets, the higher the sampling rate and, therefore, AF performance improves. But as light levels drop off, the sampling rate decreases and a point is reached where the tracking ability of the AF system is diminished. In other words, it's unrealistic to expect AI Servo AF to track fast-moving subjects as well in low light as it does in bright light."

The 1D Mark II, especially starting with Firmware Version 1.1.0 and higher, has been optimized for AI Servo AF performance in low light and with low-contrast subjects. We are confident that the AI Servo AF performance of the 1D Mark II with Firmware Version 1.1.0 and higher matches or exceeds the AI Servo AF performance of the original EOS-1D when all else is equal. Naturally, light levels are not the only issue, but they can't be ignored.

On a related topic, AF tracking performance is clearly a separate issue compared to AF accuracy. This becomes an important distinction when you take into account the fact that the Service Department can check AF accuracy, but they cannot check AF tracking performance. Essentially, they (and we) rely on the concept that as long as AF is accurate on a static subject, tracking performance is expected to perform accurately up to its limits, which can and do vary based on a wide range of factors including light levels.

If you feel that your EOS equipment is not focusing correctly on static subjects, then it makes sense to have the equipment examined by Canon Factory Service Center technicians. The FSC starts by checking the performance of the camera bodies with a "tool lens," i.e., a lens that is known to perform well within design specifications for AF accuracy. Once the cameras have been calibrated with the tool lens, it becomes possible to check the performance of individual lenses owned by the customer. Since the lenses contain their own CPUs, they can also be adjusted if necessary.

As a general rule of thumb, we don't necessarily advise sending in any equipment until you have had a chance to perform your own tests with static subjects to determine whether your focusing issues are camera-related, lens-related, or both. Like it or not, the only way to find out is to test the equipment. Of course, the FSC can do that for you, but any sample images you can provide that illustrate the problems being claimed may be helpful in diagnosing them.

I would suggest that you contact Canon's Jamesburg Factory Service Center at 732-521-7886 to determine the best possible turnaround times, once you have determined which items need to be checked. Please provide your CPS number when you call.

I am a professional photographer based in Boston and I shoot with the 1D Mark II camera. I was using the ST-E2 unit with the 550EX flash that was being held by an assistant. I had a problem with this setup today as the flash unit would only fire every other time. I don't use this lighting setup very often and didn't have time to bone up on both manuals as I decided on this lighting at the last minute before photographing two people on a location who only had 10 minutes. Can you offer an explanation to this?

Not having been there, I can only speculate on what might have happened. One thing to watch for is making sure the transceiver on the front of the 550EX is pointing towards the ST-E2. When the 550EX is in front of the camera, this sometimes requires swiveling the flash head 180 degrees so that the receiver is pointing towards the camera while the flash is pointing towards the subject. You also have to be within range of the ST-E2, which can be anywhere from 11.5 feet to 33 feet, depending on the angle of the receiver to the ST-E2. Last but not least, it's important to have fresh batteries in both units. For professional use, I would suggest connecting a Compact Battery Pack CP-E3 to the 550EX to cut down on recycling time and provide more flashes per charge.

I have a 1D and a 1D Mark II, both of which came with FireWire cords. I'm fine when I'm using my desktop computer at home, but on the road I take my laptop, which only has USB ports and a small (4-pin, I believe) FireWire port. So far I haven't figured out how to connect my cameras to my laptop. Any suggestions or workarounds?

I, too, have been faced with this issue since one of my laptops has a 4-pin FireWire port. There are various 6-to-4-pin FireWire plug adapters available that look like they should work, but I haven't found any that do. However, all of the Canon cables I've tried seem to work fine. In your particular case, here is what I would recommend:

1. For the EOS-1D, use the IFC-200D4 cable that came with the 1D Mark II. The 4-pin end goes to your computer while the 6-pin end goes to the 1D.

2. For the EOS-1D Mark II, use either the optional IFC-200D44 or the optional IFC-450D44 cable. These are 4-to-4 pin cables that differ only in length (2 meters or 4.5 meters). You can order them from most dealers who carry EOS-1D-class digital SLRs.

When shooting longer time exposures such as those in the 30 second and longer range with EOS-1D Mark II, it seems to really take it out of the battery quick. I was pretty sure I had a fairly fresh battery in and after shooting 40-50 exposures in this manner, it was done. Normally, the batteries last for weeks. Just wondering if it takes more out of the battery than normal use. Seems like it would. Sensor is active so much longer. Just wanted to know if it was my imagination or not. I also was using the reduced noise mode with those time exposures. Very pleased with the photos by the way.

With the 1D Mark II, a fully-charged battery should last for approximately three hours' worth of time exposures, which could very well turn out to be only 40 to 50 shots depending on how long each exposure is.

I own the 20D and 580ex flash and absolutely love both. I want to use the custom function #8 Quick flash at a wedding and wanted to know if there is any loss of flash power when in the quick flash mode. Specifically, will the flash consistently reach the subject with enough power to light up? I understand this mode may use considerably more battery power.

In QuickFlash mode (i.e., when the green LED is on while the flash is recycling), the 580EX is only partially recharged and cannot provide a full-power burst. You can still get a good exposure as long as you are within the usable distance range for the power that's available, which can be anywhere from 1/16 to 1/2 power. It ultimately depends on how you shoot. For faster recycling and more flashes per set of batteries, use a relatively high ISO like 400 or 800, choose a moderate aperture like f/5.6 instead of f/8 or f/11, get close to your subject (5 feet is much better than 15 feet, for example), and avoid the use of bounce flash or diffusers. I would also suggest the use of an external powerpack like our Compact Battery Pack CP-E3 with fresh lithium or NiMH AA batteries. You can check the accuracy of your flash exposures on the camera's LCD screen, or watch for the flash exposure confirmation signal on the back of the 580EX after each shot.

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

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.)