When I first took up photography, I was always told a quick rule of thumb dealing with shutter speed and camera shake, for 35mm.
"If you were to set the minimum shutter speed to be the same as the focal length, you shouldn't be effected by camera shake"
So, if I had a 50mm lens on, I should be able to readily hand hold @ 1/50th. For me, I have generally found this works quite well (OK, I can probably hand hold a bit slower). Do others use this rule, or is it total bunk. If others do, how would you apply this to say, 6x7 Medium Format?
The rule of thumb works well for SLRs, if I'm careful. There's always that mirror slap that becomes a limiting factor. With a rangefinder or other mirror-less camera, I can usually go one stop slower, again if I'm careful.
This rule is a good reminder for me to make sure to pay attention to the actual focal length on a zoom lens when shooting handheld if the light starts to fail a little.
As Ian said, this is a 35mm rule of thumb, and it works for images when sharpness is not critical. But, to get the highest resolution possible, the use of a tripod is essential, and the rule-of-thumb, requiring nothing less than the reciprocal of the focal length as the maximum exposure time, is inadequate. Attached is an enlarged picture sequence showing, from left to right, the results of photographing a point light source, at a distance of 5 m, with a handheld 50mm lens, at 1/60, 1/125, 1/250 and 1/500 of a second. The suggested time of 1/60 s is far from adequate. It took as little as 1/500 s to eliminate camera shake completely. But, the tripod-mounted camera delivered a perfect result at 1/60 of a second.
As Ian said, this is a 35mm rule of thumb, and it works for images when sharpness is not critical. But, to get the highest resolution possible, the use of a tripod is essential, and the rule-of-thumb, requiring nothing less than the reciprocal of the focal length as the maximum exposure time, is inadequate. Attached is an enlarged picture sequence showing, from left to right, the results of photographing a point light source, at a distance of 5 m, with a handheld 50mm lens, at 1/60, 1/125, 1/250 and 1/500 of a second. The suggested time of 1/60 s is far from adequate. It took as little as 1/500 s to eliminate camera shake completely. But, the tripod-mounted camera delivered a perfect result at 1/60 of a second.
Ralph, well said and demonstrated. The rule of thumb is exactly that, and provides only a guide for reasonably acceptable sharpness under difficult lighting conditions.
Very interesting! Putting that into context, how enlarged is that shot? Also, the shot that was done on the tripod, was Mirror Lock Up used? You have me very curious!
The rule of thumb is a good rule, expressing the relation between focal length and the magnification of shake.
But it's not just the focal length you need to keep an eye on when deciding what speed to use. The condition of the support (i.e. you) plays just as large a roll.
Just after cycling up Mont Ventoux, even a very fit athlete will have trouble holding a camera steady at the fastest shutterspeeds. Even more so if that mountain lives up to the popular explanation of its name and there is a stiff breeze blowing that athlete about.
That sort of thing.
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Originally Posted by RalphLambrecht
