Many readers will be aware of Leica afficionado Erwin Puts and I'm sure you'll have your opinions about him both pro and con. Erwin is one of those writers who tends to incite annoyance and enjoyment in equal measure. His critics accuse him of being overly-enthusiastic about Leica products but many fans of the German marque love him for the same reason.
I've always liked reading his stuff although it can get a little on the technical side (for me) so you have to pay close attention. I was one of those who once thought he was blind to any Leica deficiencies and slow to see the merits in the lenses of rival makers but if you take the time to really understand the points he's making then that criticism tends to evaporate.
I'm writing about Erwin because I visited his website a week or two ago and found that he'd revamped it, ditching many of his older articles in the process. I'm not sure when this happened and it could have been some time ago. A quick trip to his old site via the Wayback Machine revealed that much of his earlier material was still viewable. But the question was, "For how long?" There's much of interest there and it would be a big loss if it were to evaporate as sometimes happens on the internet.
RedesignSo I wrote to Erwin suggesting I could find a home on The Online Darkroom for his older articles to ensure they were still around in years to come and easy to find. This seemed to have set him thinking and in his reply he revealed that he'd redesigned his website to make many of the posts available again but I could add them to my blog if I wanted. I had a look at his website and Erwin has done a good job of pulling up the old stuff and making it accessible so I'm happy to leave it at that.
However, re-reading one Erwin article I was struck by something he said when discussing those factors which take the edge off "sharpness" (Erwin doesn't like that word but I'll leave it to you to discover why). Specifically, it concerned the oft-given advice to new photographers that they should aim for a shutter speed that is at least the reciprocal of the lens focal length, so 1/30th for a 28mm, 1/125th for a 105mm mm lens, etc. Rubbish, said Erwin. He states:
Using a camera without support, that is handholding, is the most important cause (of image degradation), especially when combined with slow shutter speeds. A speed of 1/250, pressing the camera against your forehead, will generate more degradation than using a full second on a stable tripod.This "rule" has been bandied about for as long as I've been taking pictures so where did it come from and who decided that the reciprocal thing made sense? It might not be quite so important if you're using medium or large format but it's obviously a good idea to get the sharpest neg you can when shooting 35mm because of the larger degree of enlargement often required.
The validity of the classical rule: a safe shutter speed is the reciprocal of the focal length (1/50 for a 50mm lens, 1/250 for a 200mm lens) has never been demonstrated. My testing indicates that the minimum is 1/250 for focal lengths from 15 to 50mm and at least 1/250 for 75 and 90mm. A longer focal length and of course the variolenses demand 1/500 to 1/1000 for best performance.
Of course, the complementary advice that the sharpest lens is a tripod - or words to that effect - has also been around for decades so people have long recognised the value of a solid support. However, I've never really thought it necessary to use a shutter speed of 1/250th with a standard lens to minimise camera shake. How much sharpness have I been forgoing by the use of 1/60th?
Erwin's other sharpness-shedding no-no's are inaccurate focusing, improper exposure, too small an aperture (leading to diffraction) and poor quality filters. Fair enough. But it's his claim about the minimum shutter speed that's got me worried - especially where my dull day shots are concerned!
If you want to immerse yourself in some technical know-how then Erwin's site will keep you reading for days.