I've had the pleasure of knowing TDJ founder Dirck Halstead and fellow columnist Bill Pierce for many years. They exemplify the meaning of the term "professional photojournalist," not only by reaching the top positions in their field, but perhaps more importantly by unselfishly and generously continuing to share their knowledge and expertise with fellow photographers through this Web site, among other things. In that spirit, it is an honor and a privilege to be invited to produce a monthly column for The Digital Journalist.

Some of you may know me through trade shows or various on-site pro photographer support operations that Canon has participated in over the past 23 years. Others may be familiar with some of the written material I've produced for Canon or contributed to various Web and pre-Web photography forums since 1989.

For those of you who may not know me, this first column is a chance to introduce myself and set the tone for what I hope will be an ongoing exchange of helpful ideas and useful tips on various imaging technology and photo equipment issues.

Before we move on to the Tech Tips column for this month, let me assure you that this space will never be used to advertise, endorse or promote Canon products: There are plenty of other sources for that. The focus of this column will always remain brand-neutral. But as a reader, 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. (An e-mail address for inquiries will be announced later this month.)

To get the ball rolling, here are a couple of frequently asked questions that may interest you:

Q: Is it safe to use studio strobes or other non-dedicated flash units on my digital SLR?

A: The answer depends on the trigger circuit voltage of your flash vs. the acceptable trigger circuit voltage level of your camera. (Trigger circuit voltage is fed to the camera through your flash sync cable or hot shoe, and can be measured with a voltmeter.) Many professional digital SLRs, including all of the EOS-1 class models as well as the 20D, can handle trigger circuit voltages up to 250V because they generate their X-sync signals electronically, but older models like the EOS 10D, D60 and D30 generate X-sync mechanically through their shutter units. Cameras of this type typically should not be subjected to trigger circuit levels higher than 6 volts. If you are not sure of your camera's TCV rating, we suggest that you check with the manufacturer before connecting a studio strobe or non-dedicated flash. Independent accessory manufacturers offer relatively inexpensive "sync filters" that reduce TCV. These devices can come in handy when you need them.

Q: I am experiencing backfocus problems with my digital SLR. What should I do?

A: The first step in troubleshooting this issue is to isolate which component is causing the problem: camera or lens. Take some test shots first, and then examine the results. If the camera has a consistent focusing problem with several different lenses, then it's reasonable to assume the camera needs an adjustment. If you are getting sharp results from most lenses but not all, then it's reasonable to assume that the lens in question may need an adjustment. The next step is to have the faulty item(s) calibrated by a qualified service technician.

The calibration procedures for each component are done according to the known specifications for that component, not for one component to match another. First, the camera body is calibrated with a "tool lens," i.e., a standard lens known to be operating correctly according to design specifications. Once the body is autofocusing correctly with the tool lens, then the camera can be checked against other lenses. Calibrating a lens does not damage its performance with multiple camera bodies as long as the calibration standards for the lens are independent from the calibration standards for the body.

That's it for now. See you in June!