# Shutter speed and lens focal length

Discussion in 'Beginner Questions' started by hjoseph7, Mar 13, 2011.

1. ### hjoseph7

The formula for hand holding a lens while taking a picture is that the shutter speed should equal, or surpass the focal length of the lens. So if I'm shooting with a 100mm lens hand held, I would use a shutter speed of 1/125, a 50mm lens 1/60th and so on. Now supose I'm hand holding a 70-200mm lens and I am zoomed out at 80mm what would be the proper shutter speed to use ?

2. ### jimmckinnon

The rule of thumb you refer to pertains to the focal length you are shooting at. 80mm would seem to dictate the next shutter speed after 1/80th. There are other factors that cause this to be a rule of thumb, not at all infallible. If that 80mm is on an APS-c sensor, you would use 120mm in your formula. If you have nerves of steel and are in great shape, you may be able to hand-hold with good results slower than the inverse of the focal length. Conversely, if you are somewhat less steady than the "average" person that this ROT uses as the example, then you may need a shutter speed considerably faster than said inverse.
Good starting point, but find out what works for you!

Edit/Add: Your hand-holding technique is going to affect this, also.

3. ### jcuknz

The point for 'small sensor' DSLR users is that the formulae only maybe works for the equivalent 35mm full frame camera's angle of view [ as if it was being used an a full frame DSLR ]. So that 80mm has the angle of view of a 120/128/160 depending on the "crop factor" of the camera in use and only applies for lets say 'careful' use of camera as Jim puts it above ... so that is 1/120 1/128 and 1/160 for a 4/3 camera.
It relates to 'angle of view' rather than the focal length ... a small but important distinction as for instance the 80mm lens on my old MF Rollieflex was a moderate wide angle lens whereas on an APC DSLR it is a moderate telephoto ... or better put medium-long focal length lens because telephoto refers to the way the lens is constructed if I remember my basic learning. That's nit picking of course.

4. ### colin carron

That shutter speed = (inverse of focal length in mm) X seconds rule of thumb is just a useful ball-park figure for the longest shutter speed you should be using if you want best sharpness. Usually a faster shutter speed than this mnimum is better for a sharp picture. But some people will be able to hand hold a camera at slower speeds for the results they want.
So the 'proper' shutter speed at 80mm for best sharpness, hand-held, would be:
'as fast as you can make it balanced against apeture and ISO'.
Obviously that then depends on the lens you are using - is it good at full aperture? or is it noticeably better one or two stops down? How much more noise do you get when you bump up the ISO? How much do each of these factors contribute to sharpness and where is the best combination?
Of course if you are using a tripod or want blur for creaive reasons then none of this applies.

5. ### paddler4

Might help to focus on the reason for this. The longer the focal length, the greater the effect of angular motion if you don't hold the camera still. Therefore, the guideline for shutter speed is an inverse of focal length: the longer the focal length, the less time you can keep the shutter open before your hand movements mess things up. What matters is the focal length at which you are shooting, not the numbers on the lens, so if you are shooting 80 mm, it makes no difference which lens you are getting to reach that focal length (except that one lens may be harder to hold than another). The guidelines were for 35mm cameras, so with an APS-C camera, multiply the focal length by 1.6.
As people said, it is only a rough rule of thumb, but it is a good starting point if you have fairly good technique. E.g., keeping your left arm bent and your left elbow stabilized by your chest. Pixel-peep a couple of shots, and you will see whether the guildeline needs adjustment for your technique.

6. ### jim_manganella

If you have a vibration reduction lens you can throw these theories out the window. I've shot a lot at 200mm, 1/60th sec with excellent results. This is using a Nikon.

7. ### jcuknz

I don't trust OIS or VR but simply try to take care how I take photos, particularly how I press the trigger, gently. Have a quite satisfactory 2000mm AoV shot taken at 1/400 but don't know if to give OIS the credit as I have another 950mm AoV at 1/20 .. a fluke for sure.
When you have a choice you follow or better the rule, when you don't have choice you take care and hope for the best. When you want to be absolutely sure you use a monopod or tripod.
There is another angle to shutter speed which relates to subject motion. If the subject is approaching or departing from you there is less displacement within the frame than when the same object is crossing the frame [ unless one pans with the subject ] Another parameter is the 'solidness' of the subject ... like a panel truck v. person or animal walking with limbs moving faster than the central bodymass. Distance of subject from camera with a given lens also affects displaement. I think I saw that with a car and trailer approaching me with front of car blurred but trailer not.
It is a matter of displacement either though the subject movement or camera shake. Amplified by enlagrement in print size. There is a great shot by Colin Carron on this page with tremendous depth of field which I guess meant a slow shutter speed even in bright sunlight? [ Handrail leading to building and clouds in sky]

8. ### jpo3136b

You can probably hold below 1/60; but, favor 1/250. Stabilize by the narrowest range available. When the advice was coined, there weren't any two foot long super zooms. If you were trying to handhold an 18-300mm, then it would be obvious that it's not the same as hand-holding most 35mm primes.
If that lens is longer than "Mister Happy," then you need to use a tripod.