Best optical F-stop: I have read that, from an optics perspective only, F-8 is in general the best optical setting for most lenses (though obviously not every image will be best at...

grahamfourth

I have read that, from an optics perspective only, F-8 is in general the best optical setting for most lenses (though obviously not every image will be best at F-8). If this is true, does this suggest that parameters such as diffraction and aberrations are minimized at F-8? Some other reason? Or is this simply not true and F-8 is not generally the best optical condition?

Thanks in advance for your help, it is much appreciated.

jackpinoh Loc: Kettering, OH 45419

It doesn't make any difference 99.9% of the time. 1) it depends on the lens; 2)Subject, composition, lighting, depth of field, and exposure time are much, much more important; 3)You will only see a difference in image sharpness if you are lab testing the lens or shooting at multiple f-stops and pixel peeping; 4)No one has ever looked at a photo and criticized it because the photographer didn't use the f-stop that was sharpest for the lens used.

MT Shooter Loc: Montana

grahamfourth wrote:

I have read that, from an optics perspective only, F-8 is in general the best optical setting for most lenses (though obviously not every image will be best at F-8). If this is true, does this suggest that parameters such as diffraction and aberrations are minimized at F-8? Some other reason? Or is this simply not true and F-8 is not generally the best optical condition?

Thanks in advance for your help, it is much appreciated.

Photojournalists used to say "F8 and be there". It was more for standardization than anything else.
In the real world there are LOTS of variables to be considered before taking the shot, aperture is only one of them.

CHG_CANON Loc: the Windy City

"f/8 and be there" assumes you couldn't afford better equipment.

Did you pay a premium for a f/2.8 lens that is as sharp at f/2.8 as any aperture setting? Do you have a cheapish nifty-fifty that is as sharp at f/4 as a 10x more expensive lens that opens to f/1.2?

Did you set-up a tripod and test your lens and camera combination at every aperture, in aperture priority, from the max to the minimum for the lens on that body? Did you review the results on your computer for the center and corner sharpness at the 1:1 pixel-level details, judging the optimal aperture / aperture-range?

Did you look at the downloadable image results from a review site and compare those to the MTF charts published by the manufacturer to confirm the visual results / aperture settings against the "MTF - Modulation Transfer Function".

Or, did you read an old wives' tale on the internet and take it as gospel?

William Loc: Mississippi

f-8 f-32 what's the big diff

hand hole lens idea
hand hole lens idea...

(Download)

William Loc: Mississippi

the shutter rules all ideas

now it is a shutter effeck
now it is a shutter effeck...

(Download)

William Loc: Mississippi

F-64 group has issues

we find most never was

there to know what F-64

gob smacked me again man

like dinner
like dinner...

(Download)

William Loc: Mississippi

CHG_CANON wrote:

"f/8 and be there" assumes you couldn't ... (show quote)

you are the old wives we hereard sosoon

next ole wives tale sorry I heard it before

sorry you will never know what's importent like the Lords Prayer

(Download)

William Loc: Mississippi

our father in heaven hallow be thy name

king dome will be done
king dome will be done...

(Download)

mwsilvers Loc: Central New Jersey

grahamfourth wrote:

I have read that, from an optics perspective only, F-8 is in general the best optical setting for most lenses (though obviously not every image will be best at F-8). If this is true, does this suggest that parameters such as diffraction and aberrations are minimized at F-8? Some other reason? Or is this simply not true and F-8 is not generally the best optical condition?

Thanks in advance for your help, it is much appreciated.

While it is a generalization, rather than a rule, many, if not most quality lenses tend to reach their sweet spot around two to three stops down from wide open. On a fast lens the sweet spot might be f/2.8 to f/4. On a slower lens it might be f/5.6 to f/8. There is no general one best f/Stop for all lenses. The sweet spot is when a stopped down lens is at it sharpest across the frame, and additional stopping down does not improve the sharpness.

William Loc: Mississippi

thy will be done

on erth man
on erth man...

(Download)

William Loc: Mississippi

as in still heaven

wide open is correct
wide open is correct...

(Download)

CHG_CANON Loc: the Windy City

William wrote:

you are the old wives we hereard sosoon

next ole wives tale sorry I heard it before

It's rather poor online behavior to litter on another person's thread. Why do think this litter contributes to the OP's discussion? There was no aspect of the post that suggested 'please dump a bunch of litter on this thread'.

srt101fan

William wrote:

thy will be done

Someone asks a legitimate photography related question and you use his topic as a vehicle to litter. Shame on you.

William Loc: Mississippi

mwsilvers wrote:

While it is a generalization, rather than a rule, many, if not most quality lenses tend to reach their sweet spot around two to three stops down from wide open. On a fast lens the sweet spot might be f/2.8 to f/4. On a slower lens it might be f/5.6 to f/8. There is no general one best f/Stop for all lenses. The sweet spot is when a stopped down lens is at it sharpest across the frame, and additional stopping down does not improve the sharpness.

wrong