Shutter speed

Messages
8,064
Name
Andrew
Edit My Images
No
What the rules of thumb for min shutter speed for portraits to stop camera shake of my daughter who 13 month old
 
The basic rule is 1/(focal length x crop factor).

So, with a 50mm lens on a DX size DSLR (crop factor approx 1.5) this would give:-

1/(50 x 1.5) = 1/75th of a second.
 
There's the rule of thumb as explained above as a minimum shutter speed for a given focal length will help to stop camera shake but then there's a shutter speed you need for specific subjects/effects and this will depend on how fast the subject is moving.
 
This came up on the Zack Arias Creative Live thing the other day and he said that the crop factor doesn't come into it as the length of the lens doesn't change. His rule was the simple 1 over the shutter speed whether it was FF or crop.
 
I find it depends on the speed of the subjects movement when you are shooting above 1/50th. Especially if you are trying for big beatiful sharp eyes and you are not using flash :)
I constantly photograph my siamese cats and more often than not the cause of any softness is their movement - not mine !! And that is often @ much higher focal legnths.
 
This came up on the Zack Arias Creative Live thing the other day and he said that the crop factor doesn't come into it as the length of the lens doesn't change. His rule was the simple 1 over the shutter speed whether it was FF or crop.

The length of the lens doesn't change but the magnification factor when printing does.

To print to a given size the DX image (24 x 16mm for Nikon) needs to be enlarged by approximately fifty percent more than a 35mm image (36 x 24mm). Any movement caused by the shakes will be the same size on both sensors (because the lens has the same focal length) but will be enlarged by an extra fifty percent when printing the DX image to the same size as a 35mm.
 
Without getting back into the crop factor arguement, I would agree with Syd. The speed required to freeze the little chap(ess) is going to be rather higher than that required to beat camera shake.

(Oh - by the way Stratman is spot on.)
 
This came up on the Zack Arias Creative Live thing the other day and he said that the crop factor doesn't come into it as the length of the lens doesn't change. His rule was the simple 1 over the shutter speed whether it was FF or crop.

If that was true you could just use a compact and get away with amazingly long shutter speeds. For the same reason (as explained above by Stratman) the shutter speed rule should also be adjusted for cropping - enlarging half the frame area, multiply by an additional 1.4x.

Did Zack Arias really say that? He does come out with some strange things sometimes :nono:
 
paulcamcas said:
This came up on the Zack Arias Creative Live thing the other day and he said that the crop factor doesn't come into it as the length of the lens doesn't change. His rule was the simple 1 over the shutter speed whether it was FF or crop.

If you stop and think about WHY there is this "rule" you will understand why that statement just doesn't work.

The longer the focal length the narrower the field of view, which is made narrower on a crop sensor. If you have a lens of 100mm and you move your camera back & forth by 1 degree the amount of movement across the frame will be noticeable, so you multiple the focal length by 1.5/1.6 and the movement across the frame become even worse.

It is a very individual thing, but most of us cannot hand hold a camera below the rule without a great deal of practice. I've seen shots taken with a 50mm lens at 1/10 of a second, by experienced photographers. Personally I know I don't have the steadiest of hands and like to work at FL x 2.

Steve
 
If you stop and think about WHY there is this "rule" you will understand why that statement just doesn't work.

The longer the focal length the narrower the field of view, which is made narrower on a crop sensor. If you have a lens of 100mm and you move your camera back & forth by 1 degree the amount of movement across the frame will be noticeable, so you multiple the focal length by 1.5/1.6 and the movement across the frame become even worse.

It is a very individual thing, but most of us cannot hand hold a camera below the rule without a great deal of practice. I've seen shots taken with a 50mm lens at 1/10 of a second, by experienced photographers. Personally I know I don't have the steadiest of hands and like to work at FL x 2.

Steve

Quite. It's actually nothing to do with focal length directly, but with magnifcation of the image. It just so happens that the numbers coincidine conveniently with full frame, and they can also be easily converted for other formats.

It's also quite easy to beat the rule by shooting several frames at once, which is often a good emergency technique. If you shoot a series of half a dozen shots at just below the threshold, they will usually be blurred to different degrees and one of them will probably be pretty sharp. Doesn't mean you can do it all the time though.

Edit: Bear in mind that camera shake is always present, it's just that faster speeds reduce the effect to an acceptable level. If you have a high m'pixel camera with a fine lens and want to get the best from them, then pixel peepers should raise the threshold point - it makes a difference.
 
Last edited:
Back
Top