'Stopping Down'

J

james-bailey

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James
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Ive seen this term mentioned quite a lot, what does it actually mean? Is it going from like 1.8 to f/5.6?

Cheers

James
 
Yes :) It'll give you more depth of field and usually.. sharper images! (Until you hit the lenses sweet spot, then it'll fall off again)
 
Thats what I thought, thanks.

So each lens has a sweet spot, does this spot change due to other settings or is it techically the same for each different lens?
 
I believe it's a lens thing, camera settings won't affect it.
 
It's a lens thing and is normally about 2 stops down from the maximum aperture, so simply multiply the maximum aperture by two (1.4 x 1.4). This is a rule of thumb only - you'll need to experiment with your lenses to find the sweet spot for each.
This doesn't mean that you should shoot landscapes at f5.6 with an f2.8 lens though!


As you go above (say) f16, diffraction comes into play and can become noticeable above (say) f22.
 
Diffraction is related to pixel density. I found the 7D start to diffract at about f/8, with the 5D classic it was about f/16 before I noticed it.

I don't know the formula I just noticed it when I was borrowing and loaning cameras. So I'd say a 40D would probably start diffracting around f/11? But I've not used a 40D so I don't know.

And yes, stopping down is just closing the aperture further. So if you shot at f/8 and someone says 'should've stopped down for more depth of field' they just mean close the aperture to f/11. Same if your shooting at f/1.2 and someone says 'perhaps stop down to get the eyelashes in focus!'.
 
And in the old days,the real old days :p
The lenses did not stop down automatically like today.

You focused manually wide open for a clear picture,Then stopped down manually to desired f/stop ,then took pic.
Hence a lot of blown out shots where togs had forgot to stop down.
And that was in the age of film where it cost you money :eek:
 
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