shutter speed when hand holding

fguihen

I have read about when hand holding the camera, there is a minimium shutter speed, based on the focal length of the lens. eg, 200mm lens = 1/250 secs.

Lets say i have a 200mm lens, does the 1/250 secs apply at all times, or only when the lens is at 200mm. If i have the lens set to 100mm would it be a different value?

nilhg

The general rule of thumb for non stablised lenses is 1/the effective focal lenght of the lens, ie 100mm lens on a 1.6 crop factor camera gives 160mm EFL needs 1/160 sec.

This is only a rule of thumb though, some people consistently do better, others worse.

quilmore

IS or VR help to bring it to a quarter of what the minimum should be without it
and it's all a probabilities game
at any given length and any given shutter speed you'll get a percentage of sharp pictures
1/250 on a 200mm will probably give you over 50% chances to get a sharp picture
if you go for 1/100 you may get a 5% of chances, in that case, what I'll do (if the circumstances allow for it) is to take 30 or 40 pictures
that, statistically will give me 1 or 2 sharp pictures

sasar

I have to say it really depends on your handshake. I can hold it up to one second on 17mm. If you are steady so can you, if not you might need something like 1/20.

fguihen

thanks guys. Sorry, my question wasnt well phrased. what i meant to ask is:

if the min shutter value for a 200 mm lens is 1/250 at full zoom, but i use the lens at 100mm, will the min shutter value become 1/160, or should the recommended min shutter speed be 1/250, regardless of what focal length i have the 200mm lens at?

Paulw

Again, it's 1/focal length. So, at 200mm (on a 1.6 crop), it's 1/320. At 100mm it's 1/160, at 70mm it's 1/112, and so on.

fguihen

sorry for the continued questioning on this topic, but i have one more. Why, the longer the focal length, the shorter the exposure? is the apature wider the more you zoom in?

nilhg

fguihen wrote: »

sorry for the continued questioning on this topic, but i have one more. Why, the longer the focal length, the shorter the exposure? is the apature wider the more you zoom in?

No, the angle of view (roughly = to magnification) is narrower the farther you zoom out, therefore any small movements have a greater effect. The aperture would have very little if any effect.

quilmore

you can see your vibration as a tilt in the angle the camera is aiming at your subject

if you move 0.5 degrees (0.5 is a guess) on a frame covering 66 degrees (18mm on film) it's probably not noticeable

but if you move the same 0.5 degree on a frame covering 8 degrees (300mm) it's more likely to be visible

DX only makes things worse
you will be shaking in the same way but the angle of coverage will be divided by 1.5 or 1.6
so a 300 mm in a DX camera will cover just 5 degrees

deaddonkey

also, the amount of time you can hand hold with an SLR is less than anything else, because of the thumping great big mirror.

holding a rangefinder to 1/8 of a second and a sharp shot is quite possible.
this shot is f1.7 and 1/15th of a second.