Here are two reasons you shouldn't read this column - at least if you have limited time to spend on the Web. Instead, check out these sites:

(1) http://morris.blogs.nytimes.com...

This is filmmaker Errol Morris' absolutely exceptional article on what I will describe as talking too much and looking too little (or maybe just seeing what we want to see). It is a must-read.

(2) http://theonlinephotographer.typepad.com...

Somewhere in this archive of the articles that appeared in September on The Online Photographer, you will find an article entitled "Creative Livings." It's Mike Johnston's take on art and photography schools. When I started in photography you learned from other photographers. Different situations existed, but all of them were essentially apprenticeships. That has been almost totally replaced by photo schools. Some are fraudulent rip-offs; some are incredible schools that give students the knowledge to work in a medium even though the medium will change and evolve between the time they study it and the time they practice it on their own. Read Mike's article. If you are too old a dog to learn new tricks, e-mail the article to a puppy.

And now, if you are still with us, comes the regular Nuts & Bolts column ...

I noticed on one of the Leica forums that folks were setting their M8s to the lowest "film" speed, ISO 160, and then intentionally underexposing the camera's TTL meter reading by a ballpark figure of two stops. Essentially they were treating the camera as though its film speed was set to 640. The dark raw images were then corrected, brightened to the degree necessary, in Capture One, the raw file program included with the M8. This provided an amazing degree of exposure latitude.

This goes against all we have been told about raw digital images containing the majority of their information in the brighter areas of the record and suffering in quality when dark images are brightened in image-processing programs. The common wisdom has always been to expose as much as you can without losing highlight detail and tame the brightness when you convert the raw file to a TIFF or JPG.

The problem for photojournalists has always been that it has taken careful metering and checking the histogram to make sure that you have that bright image that still maintains highlight detail. In covering breaking news, an experience often so hectic that your entire being is on autopilot, it is unlikely that you are going to use a handheld incident meter, check your histogram or bracket. And, just like you, the camera is going to be on autopilot – excuse me, program mode.

Underexposing the raw and correcting the JPG looked like it might be a good way to deal with digital photography's limited exposure latitude and informationless overexposed highlights. I ran some tests with an M8 and Capture One Pro and it worked.

The next question was, would it work with other cameras and other image-processing programs? The answer ... Well, sort of. OK, really, no. Photoshop offered the strongest corrections in the exposure and saturation categories, but you could see the image beginning to fall apart. Capture One didn't look as bad, but probably because you couldn't increase the exposure and saturation levels as much. Certainly you could salvage a shot in an emergency, but you wouldn't want to do it on a regular basis.

There has been a lot of speculation about the Leica M8 raw file. There is some reason to believe it is a 14-bit file converted to 8 bit, but with a difference.

An article about the M8 in KammaGamma states, "Obviously when converting 14 bits (or 16 bits) into 8 bits, data gets compressed all over the scale. This LUT compresses data in such a way that data from the shadows gets compressed less than data from the highlights."

In other words, if I understand the article, and don't presume I do, the Leica raw file has more information in the shadow areas than some. Expose at the native speed of 160 and you have the possibility of expanding the tone range of those dark images without them totally falling apart. It may do it better than some DSLRs, but there are limits. And those advantages will diminish as more cameras move to a 14-bit raw.

What does this mean in practical terms? When I'm on autopilot and my camera is on programmed auto exposure, I set the "film" speed down a notch, adjust the raw file as necessary and decrease my chances of blowing out the highlights to detail-less garbage.

My TTL meters on my DSLRs are always set to expose a third of a stop less than the conventional exposure. (With the M8, I've always reduced the exposure by two-thirds of a stop.) This parallels Kodak's old recommendation for transparency films where they suggested the third of a stop reduction for "professionals." Transparency films with their limited exposure latitude and the possibility of turning highlights into detail-less cellophane have always paralleled some of the characteristics of the digital camera image.

As to what to do the next time you're covering a demonstration/riot that gets out of hand and you want to increase your exposure latitude ... well, there are too many variables between cameras, TTL meters, image processing programs, etc., to come up with some fixed recommendation. If I can use the lowest "film" speeds on the camera and shoot raw, I set the M8 down a full two stops and my Canon 5Ds down a stop.

The only problem is that I haven't shot any riots since I started playing with this technique. So far I can only guarantee its use in pictures of rambunctious Weimeraners and grandchildren. Actually, that can be fairly close to a riot.

This month's picture that has nothing to do with the techy stuff is of Marcel Marceau. He recently died at age 84. The picture is from Marceau's "Seven Ages of Man"; this is the last age, death. It was made during the filming of John Barnes' movie on Marceau. The lights were being extinguished after the take and the front lights were turned off a second or so before the backlights were.

Marceau once said to me, "I am a great mime. Do you like what I do?" He wasn’t being cute, condescending or insecure. He was talking about what was important to him and, in those words, taught me much of truly good performers.