Shutter speed/focal length

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Andy1962

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As a general rule I have been told that your shutter speed shouldn't be slower that the focal length of your lens; which is fine if you are using a prime.

However what if you are using a zoom say, 70 - 200mm If you start at 70 mm you shouldn't go slower than 70th of a sec, then should you 'zoom' in to say 100mm, do you then have to use 100th of a sec as your slowest speed or is there another formula or do i still use 70th sec or go to 200th of a sec?
 
The shutter speed needs to be at least the focal length you are actually using. Actually, that is a 35mm rule - in digital, Full Frame. For a crop body it will be at least the focal length x 1.6.

Doesn't apply if you use a tripod or have image stabilisation in your lens.
 
And it would be double the focal length if using M43.

Except that if you use something to lean on and don't mind taking lots of shots in order to get one sharp then it might be 2-4 times as long as that. There are times I would be happy to lean on something and use 1/15th or 1/8th with the equivalent of a 28mm lens, taking 10 or 15 shots to be sure of at least one sharp. Sometimes a small amount of motion blur is entirely acceptable.
 
Andy1962 said:
As a general rule I have been told that your shutter speed shouldn't be slower that the focal length of your lens; which is fine if you are using a prime.

However what if you are using a zoom say, 70 - 200mm If you start at 70 mm you shouldn't go slower than 70th of a sec, then should you 'zoom' in to say 100mm, do you then have to use 100th of a sec as your slowest speed or is there another formula or do i still use 70th sec or go to 200th of a sec?
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if you're at 100mm then it's 1/100... Modern Nikons have a setting in auto ISO that will match the minimum SS to the current FL (or a settable offset).

FWIW, IMHO the general rule/ROT is kind of crap... it was "OK" when sensors were 12MP or less...
Most people cannot handhold reliably below 1/60th or so regardless of the FL.
Everyone has a different level of stability/technique.
If you want truly sharp, instead of acceptably sharp, it should be more like 2-3x FL.
It *should* take into account pixel size/resolution, but doesn't... some apply crop factor to the rule as an approximation.
It doesn't take VR into account... not a big deal IMO. VR has a very lax standard for "sharpness" (don't rely on it unless you have to).
It doesn't take the subject into account, it assumes a stationary subject... not really a big deal, but some fail to consider that separately.

In other words, ignore the rule. Use as high of a SS that suits the subject/situation you can achieve. When SS starts getting towards 1/FL (or earlier) start thinking about other options (support/VR/flash/etc). Figure out what *your* minimum is in relation to FL/weight/sensor and apply that.
 
It's a guidline to give you an indication of what the minimum shutter should be.. it fails in real life for a lot of reasons. great if your on a tripod with a remote I guess.. But if your a skinny weakling holding a heavy sigma 120-300 for an hr in strong winds and moving about I doubt 300 shutter would suffice :)
 
Firstly, yes it changes as you zoom.
But 2ndly it's just a guide, you should work out what's right for you and your shooting conditions. As Kipax says a 300mm 2.8 lens in the wind is a different challenge to a 300mm kit zoom with good technique.

And it says nothing at all about your subject, a tripod mounted rig won't get a sharp shot of a standing human at 1/15 due to their breathing and stance.
 
Also consider the subject.
A brick wall is fairly static, even if it's breezy, but a bird sat still in the breeze will still show feather movement, so you'd need to up your speed considerably.
 
Whatever standard you want to work to, lets say 2x effective focal length for critical work after doing some personal testing, that should hold good at all focal lengths (within reason).

That's 'effective' focal length in full-frame terms, so must be adjusted for crop factor. Also, if you crop an image further in post processing then that also increases the effective focal length.

Testing your own limits and personal hand-holding technique is a very good idea, to know exactly where you are. You'll find that when you're on the limit and compare a sequence of images, they will not be all evenly blurred - some will be sharp, some will be rubbish, some more or less acceptable. The point there is that when you're up against it, there's safety in numbers. If you can shoot a handful of frames in quick succession, eg in continuous shooting mode, your chances of getting a sharp one are dramatically increased.
 
john.margetts said:
that is a 35mm rule - in digital
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I would say it's a basic rule for film and doesn't work with growing sensor density, except you never zoom in. ;)
 
KIPAX said:
It's a guidline to give you an indication of what the minimum shutter should be.. it fails in real life for a lot of reasons. great if your on a tripod with a remote I guess.. But if your a skinny weakling holding a heavy sigma 120-300 for an hr in strong winds and moving about I doubt 300 shutter would suffice :)
Click to expand...
Been there so know what you mean.
 
Cheers gents. cleared it up for me nicely. So this week, after the Army v Navy rugby, I am to put this advice into practice.
 
ancient_mariner said:
And it would be double the focal length if using M43.

Except that if you use something to lean on and don't mind taking lots of shots in order to get one sharp then it might be 2-4 times as long as that. There are times I would be happy to lean on something and use 1/15th or 1/8th with the equivalent of a 28mm lens, taking 10 or 15 shots to be sure of at least one sharp. Sometimes a small amount of motion blur is entirely acceptable.
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What is M43 please?
 
The 'guide' for 35mm, comes from notion that the more 'magnification' you have on a lens, the faster the shutter speed you likely want, hand-holding, to avoid blur from camera or subject movement, being like-wise magnified in the frame. So it's a guide, in so much as it really depends on your subject and how steady you hand-old the camera...

eg; shooting kids in the garden with a 50mm, you might struggle to stop the little blighter's blurring even at shutters over 1/125th, when 'guide' would suggest you could go as low as 1/50th.
Alternatively, with a steady hand, taking a shot of a bit of architectural detail with a 135mm tele, you might get away with something as low as 1/30th if your hand is steady enough....

Not seen it mentioned in reples vis zoom; but question used to pop up in the mags often enough in days past, as to how to apply the guide with a zoom, and whether to use a shutter speed = or faster than the focal length 'set' on the zoom, or a shutter speed faster than the shortest or fastest focal length of the lens... answer was usually to 'tend' to err towards a shutter above the longest focal length of the lens, even if you are shooting it at a shorter setting, due to the length & weight of the lens effecting how steady you might had-hold it.

Eg; if you are shooting a 70-210, you might get away with a shutter as low as 1/50th at the wider end, but more reliably you'd be better off shooting at 1/250th, even if set at 70mm, due to the bulk of the lens and the ;leverage it has when wobbled.

That advice was increasingly appropriate with longer reach zooms then, even though they often only had about 3x zoom range; these days, with zoom ranges often in the 5x or more region; plus frequently longer still than an old 'long' lens that would seldom be much over the 180-250mm region, a long lens now more usually 300+mm, and used on a crop-sensor body giving the effective reach of an old 500mm or more mirror, with the crop-factor, the suggestion is probably even more useful; for all multi-element constructions, greater use of plastic and such may have done to make modern lenses more compact than their effective focal lengths, an what benefit Image stablisaton might offer, adding that and focus motors and everything else into them, hasn't made them that much more 'stable', IMHO.
 
lemo said:
I would say it's a basic rule for film and doesn't work with growing sensor density, except you never zoom in. ;)
Click to expand...

I would say its a rule for a 6 x 4 print on 35mm. Sensor density doesn't really make any difference to that.
 
Some other basic quick wins is to squeeze the shutter gently and don't 'snatch' shots or holding your breath just before releasing the shutter. With practice the combination of these techniques can be very effective. When I was an Army photographer we used to have photo-sniping competitions who could get the the best hand held image with the lowest shutter speed just for fun.
 
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Hand-holding technique is important.

Stand at 45 degrees to the subject. Support all the weight in you left hand, cupped under the camera/lens. Press your left arm against the side of your chest, gently but firmly, so your elbow is touching the side of your stomach. This forms a supporting triangle with the camera pressed gently to your face. Your right hand is only to steady the camera and operate controls.

Edit: and there is a world of difference between good standing technique like this, even better if you can lean your shoulder against a wall, and say down on one knee, stretching out with your arms away from your body. And just to repeat what I said earlier, when you're on the limit, an easy way to dramatically increase your chances of a sharp image is to shoot a quick sequence of frames in continuous drive mode. They will all be different and there's a greatly increased chance of a good one.
 
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Musicman said:
I would say its a rule for a 6 x 4 print on 35mm. Sensor density doesn't really make any difference to that.
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I wrote: except you never zoom in. I meant the picture on your screen. Who thinks about prints these days? ;)
 
Blank_Canvas said:
Some other basic quick wins is to squeeze the shutter gently and don't 'snatch' shots or holding your breath just before releasing the shutter. With practice the combination of these techniques can be very effective. When I was an Army photographer we used to have photo-sniping competitions who could get the the best hand held image with the lowest shutter speed just for fun.
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So using the 'marksmanship principles' then . One old sweat to another.
 
Chaps , many thanks for all these tips. Looks like many a lesson taught in my army days are going to be put to good use; marksman ship principles and 5 's' are two that spring to mind
 
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