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View Full Version : Aperture - Peak Performance?


gman
26-04-2008, 15:39
I've read in quite a few places that the optimum aperture to achieve the best possible sharpness is typically F9 and F11 but it depends on the lens. Is this true and is there anywhere that tells you what the optimum aperture for each lens is?

Cheers

englandshottest2
26-04-2008, 16:09
i think that would realllllly depend on what you're shooting, sometimes in studio i shoot on f/32 as i need everything crystal sharp....but normally i'd say i have it set to f/10-11 when not paying too great of attention to changing accordingly all the time...

dazzajl
26-04-2008, 16:33
is there anywhere that tells you what the optimum aperture for each lens is

Yup. It's the photos that you take with them :D

most lenses will have the best sharpness and colour stopped down by 3 or 4 stops. Take some test shots and see where your lenses perform best. :)

Garry Edwards
26-04-2008, 16:54
It depends.

on a prime (fixed focal length) lens the best performance is usually at around 2 stops less than maximum. That probably applies to most top quality zooms too, but on a 'kit' zoom lens it's probably 3 or even 4 stops less than max, and some lenses don't perform well at any aperture.

As for shooting at f/32, that's acceptable on 5" x 4" but diffraction limitation rears its ugly head at anything smaller than f/11 on a cropped-frame digi, f/16 on a full frame digi/35mm. I've always felt it's a pity that manufacturers put impossibly-small apertures on their lenses, it encourages people to assume that the lens will produce OK results when it can't...

gman
26-04-2008, 23:59
Thanks for the replies, much appreciated.

King_Boru
27-04-2008, 04:27
sometimes in studio i shoot on f/32 as i need everything crystal sharp...

Doesnt make sense to me. Optimum lens sharpness is generally around f/16. The further you stop down the more degraded and softer the image becomes. You must have a considerably strong lighting setup too?

malla1962
27-04-2008, 08:02
Doesnt make sense to me. Optimum lens sharpness is generally around f/16. The further you stop down the more degraded and softer the image becomes. You must have a considerably strong lighting setup too?
I agree;)f8-f11 for me get a really sharp shot then end up smoothing it out in PS. I stop down for DOF not sharpness, if a lens is not sharp wide open
its no good to me.

dazzajl
27-04-2008, 08:08
Doesnt make sense to me. Optimum lens sharpness is generally around f/16. The further you stop down the more degraded and softer the image becomes. You must have a considerably strong lighting setup too?

I agree;)f8-f11 for me get a really sharp shot then end up smoothing it out in PS. I stop down for DOF not sharpness, if a lens is not sharp wide open
its no good to me.

There are times that you need to throw a big old DoF over a set in the studio and stopping down can be the only way to do that. Sometimes even with a view camera, where you can move the focal plane about there's no other way than a silly small aperture.

EdinburghGary
27-04-2008, 09:15
Soooo....

I want to take a landscape with a Sigma 10 to 20 at 10mm. Hills in backgrounds, distant city in front of hills all the way to the foreground, which will be some trees and rocks etc.

Best aperture??

DiddyDave
27-04-2008, 09:27
Soooo....

I want to take a landscape with a Sigma 10 to 20 at 10mm. Hills in backgrounds, distant city in front of hills all the way to the foreground, which will be some trees and rocks etc.

Best aperture??


On a super-wide lens anything from f8 and all will be in focus from only a foot or two in front of you (esp. with a touch of hyperfocal focussing), so f22 wouldn't really add any DoF but would soften the image as you'll be past the lens' best IQ setting

Many fast lenses produce their highest IQ wide or very close to wide open, that's the point of such a lens anyway

Macros on the other hand, are often best at very small aperture settings, I have a few crackingly sharp images from the other day shot at f45 and even f54

But the 'best' aperture setting is likely to be not an IQ issues, but what's best for the shot and DoF you're after

DD

EdinburghGary
27-04-2008, 09:53
Wow what kind of shots would require such hi F numbers?

DiddyDave
27-04-2008, 09:55
This type of Macro shot - the glass is only 3 inches high by about 1 inch wide, and was printed at A3 size - amazingly quality

DD

http://www.talkphotography.co.uk/gallery/data/500/Water_1_web.jpg

englandshottest2
27-04-2008, 16:50
Doesnt make sense to me. Optimum lens sharpness is generally around f/16. The further you stop down the more degraded and softer the image becomes. You must have a considerably strong lighting setup too?

yes obviously when i do it on that level i have around 8 strobes at 600w and up

tappilappi
27-04-2008, 16:58
I find this usefull re. DOF...............Have a play!

http://www.dofmaster.com/dofjs.html