What's a few milliseconds between friends?

I get a laugh reading the debates in forums or reviews where the subject of a camera's "reactions" are under discussion. There seems to be a perception that, for many types of photography, a camera's lag time can be crucial. A difference of five or ten milliseconds is considered of huge significance, placing the situation in the Middle East firmly in its place. Read a few of these discussions and you'll come away with the impression that the shutter release of the Leica rangefinders is the most responsive of 35mm cameras because it's a mechanical action and there's no mirror to swing out of the way. Manual focus, mechanical 35mm SLRs are next with AF SLRs and some digital cameras "lagging" far behind.

On the basis of this, some Leica owners proclaim their cameras as the best for catching the decisive moment whilst other lesser cameras are written off as too slow. Pardon me, but what a load of old cobblers. The Leica's shutter lag (averaged across the various film models) is around 15 milliseconds. The likes of a Minolta XE-1 is somewhere between 35 and 40 milliseconds. Sounds a lot but how significant is this?

Well, if you're photographing a person walking very briskly, he or she would have moved one inch in the time it took for the Leica's shutter to trip and just over two inches inches for the XE-1. I can't think of many photographs outside of sports where an inch or so makes all the difference - and you wouldn't want to shoot sports with a Leica M6 anyway. Imagine. for instance, you're on a street and you see an interesting juxtaposition of characters about to happen 20 feet away. How crucial really is that one inch difference between a Leica and the XE-1 likely to be?

But all of this is only of importance where the photographer has picked precisely the right moment to take the photograph. What if the photographer was a fraction of a second early in tripping the shutter? Obviously, then, the XE-1 would have done a better job of catching the action at the "right" instant. If a fraction of a second late in taking the photograph then both cameras would have missed the decisive moment. The Leica, therefore, is only an advantage where the photographer always takes the photograph at precisely the right instant and where a very small amount of subject movement is crucial to the photography or composition.

I don't know about you but I don't think I can say with any confidence that I could nail the decisive moment down to a few milliseconds. So the shutter lag with either the Leica or the XE-1 would be perfectly acceptable to me. Things get a little trickier as shutter lag increases. The Leica M9, for instance, has a shutter lag of 80 ms. In that time, our subject above would have moved about 5.5 inches. That might make a difference but probably not.

Photographers' lag times?

But the really interesting thing is that the average human reaction time is in the order of 200-250 milliseconds*. Therefore, if you see the decisive moment and move to take the photograph then you've already missed it by around fifteen times the lag time of your Leica. The only way to capture the decisive moment is by anticipating it and the lag time of the camera, providing it's not in the digital point and shoot range, isn't terribly important - as long as you're aware of it and comfortable working with it.

I was thinking about this the other day when I was out with my Konica Hexar AF. Being an electronic AF camera, I doubt it has the shortest shutter lag around** and yet I was still able to get the two shots in this post which, you could argue, depend heavily upon timing, using it in AF mode. I suppose a nit-picker might point to the first pic and say that a shorter lag time might have enabled me to capture the entire seagull in the frame instead of chopping part of a wing off. True, and yet I think I prefer it this way. The seagull just about to exit the frame says more about a life without limits than a bird captured entirely within in.

On the other hand, look at the arrangement of the birds in the second photograph. It really couldn't be any better. What might a shorter lag time have done to that? Well, it certainly wouldn't have improved it!

So the upshot of all this is that shutter lag times, if they're in the sub-100 ms range, really aren't worth bothering about. There may be other, good reasons for choosing a rangefinder over an SLR or a manual focus camera over an AF machine but lag times shouldn't figure heavily in the final reckoning.

* As part of my research for this post, I tested my reactions online and got an average time (of five "goes") of 185 ms, placing me 25th out of all the many thousands of people who'd taken the test that week. Not bad for a 51-year-old. Just try to imagine my cat-like reactions of 30 years ago. They were so fast I had to wait until the decisive moment had just passed before pressing the shutter. You can test yours at www.humanbenchmark.com/

** As with most autofocus cameras, it's possible to improve the Hexar AF's lag time by switching to manual focus. The Hexar also moves to the selected aperture as soon as you choose it so there's no delay when tripping the shutter waiting for the lens to stop down. In this configuration it's probably as fast as anything out there, for what that's worth..