What aperture gets the 'best' image?

Ted

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Hey guys, sorry if this is the wrong place to post this but I think it's okay. I don't quite have the eye to figure this out for myself (so it probably doesn't even matter really!), but the nerd in me is curious. At what aperture tends to capture the 'best' image? By best I mean disregarding DOF, as obviously that is going to work differently for different images. I have read that going too open can result in your image not being as sharp, but going too small can result in diffraction and, again, a less sharp image. Is there a sort of standard 'best' aperture or does it differ from lens to lens? Is it even worth thinking about or are we better off just choosing aperture based on DOF and available light? Thanks!
 

RamblinR

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The aperture and DOF is relevant to get the best image depending on the image being taken and the artist vision you have (portrait, landscape, ...)

I find m43 lenses are fabulous wide open (I come from canon) don't need to stop down unless the image requires a deeper DOF, etc etc.
 

darosk

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I think the term is "the sweet spot", least that's what I've heard used to describe it. Yeah I think it varies from lens to lens, although some 'rules of thumb' I've heard over the years are two stops down from wide open, or between 4-5.6. Maybe list your specific lenses, so anyone with experience with them can maybe chime in?
 

SojiOkita

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It depends on the lens.
You can look at reviews of several lens, I think the maximum resolution is around f/4 for most of them.

I choose the aperture based on the DOF I need. If I need to stop down to f/5.6 or less, I stop down (for example: landscapes).
There's no point of having a better theoretical resolution if part of the subject is blurred.

The same goes when I want thinner DOF. If I want the background blurred, I don't care having a little less resolution for my subject.
(on prints, I'm not sure you will see the difference)
 

eteless

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As said above, just use what you need to get DoF if the light allows it. Some of my favorite pictures I've taken lately were at F/22 which in theory shouldn't be as sharp... who cares, it can still take an amazing picture and the effect it gives cannot be replicated at larger apertures.

Technical perfection doesn't matter that much in making pictures that look really really good, I find that it can be the imperfections which make a picture feel natural and really make the viewer love it.
 

Replytoken

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I think the term is "the sweet spot", least that's what I've heard used to describe it. Yeah I think it varies from lens to lens, although some 'rules of thumb' I've heard over the years are two stops down from wide open, or between 4-5.6. Maybe list your specific lenses, so anyone with experience with them can maybe chime in?
As lens technology and design improves, the sweet spot often moves from two stops down closer to wide open, especially with more expensive lenses. But, I would be hard pressed to find a lens that is not at or near its sharpest at f/4.0 or f/5.6 (with the possible exception of very slow zoom lenses). If a lens is also sharp wide open, then all the better. In reality, I really only consider this information (among many other factors) if I am making a purchase decision between two lenses. The important thing I want to know is how the lens performs wide open, as I like to know what to expect when I am fighting for light in poor conditions or otherwise need maximum aperture. If I shot landscapes, I suspect that I would want to know how far I can stop down a lens without diffraction being an issue. It is good to know what to expect from your equipment, but I try to learn and internalize so I am not thinking about these things when I am out shooting (not unlike driving a car with a manual transmission). I have enough going on that I do not want to be worrying about technical measurements.

Good luck,

--Ken
 

Ulfric M Douglas

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... or does it differ from lens to lens?
Lens to lens, definitely,
however there are more m4/3rds (and 4/3rds) lenses which are almost at their sharpest at their brightest apertures ... than historically typical DSLR lenses.

Also to factor into the equation is what "best" image really is, and whether sharpest image is really "it".
For example I am convinced my 17mmF2.8 makes better images at F2.8 than at F5.6 ... but such stuff is very hard to quantify.
 

zulfur666

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you can always look up your specific lens on DXO mark and find the sweet spot of a specific lens. It varies by lens and manufacturer.
 

Lionroar

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My own general rule is that, on the micro-four-thirds system, prime lenses are best at f/5.6 and non-pro zooms are best at f/8.0. Of course it varies by lens, and other people will have different opinions on what is "best."
 

Promit

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Every lens is different and the imaging system works as a whole.

That said -

It's commonly accepted that lenses tend to get sharper when stopped down one to two stops from wide open. This is not universal, and m4/3 lenses in particular are designed to be sharper wide open than you'll see in many other formats. Sharpness will start to degrade due to diffraction as you stop down; at m4/3 this effect begins to appear around f/8 and is in full force by f/11. There are other issues; chromatic aberration (both longitudinal and lateral) will generally improve as you stop down, and the distortion and field curvature properties can change as well. Note that "change" does not necessarily imply "improve".

In short, you need to get acquainted with the peculiarities of a single lens to really get a good feel for it.
 

Clint

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What aperture tends to capture the 'best' image? It all depends. Every lens is unique and even in the same model of a lens there can subtle differences.

Aperture not only effects depth of field and light for an exposure but can change the perceived detail, contrast, color, noise, dynamic range, tonal gradation, bokeh, flare, distortion, and vignetting in a photo. Combining aperture with other settings and lighting can help define motion blur, frozen motion, maximize depth of field, maximize sharpness across the entire image - or any of the contrary effects.

As an example for a head and shoulders portrait with a table and flowers sitting next to the subject, using an Olympus 75mm f/1.8 lens and an equivelant exposure acroos the various f-stops:

- I may want to shoot at f/1.8 to get the head and eyes in very sharp focus with a softer appearance that radiates form the central portion of the photo to the edges, thus softening details with a slight vignetting at the edges, so that the details in the flowers are not quite as sharp as the eyes.

- Or maybe I'd like to shoot at f/5.6 and have everything in very sharp focus.

- Or maybe I'd shoot at f/16 to provide a very slight soft focus effect with the diffraction reducing the apparent details that could clearly be seen in the photo above, and providing what might best be defined as a very soft glow.

So it all depends.
 

Whtrbt7

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Is this even a real concern? Would people just choose the appropriate aperture for their subject matter? The best image is produced by the photographer, not the lens, and not the camera. If it's sharpness that people are concerned about, you choose a lens and find out where it is sharpest based on the MTF charts. An image is more than just sharpness though. There's DOF, composition, exposure, subject matter, technical specs of the image, and lens rendering. A lot of things that lead to great images are subjective and preference.
 

usayit

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Is this even a real concern? Would people just choose the appropriate aperture for their subject matter? The best image is produced by the photographer, not the lens, and not the camera. If it's sharpness that people are concerned about, you choose a lens and find out where it is sharpest based on the MTF charts. An image is more than just sharpness though. There's DOF, composition, exposure, subject matter, technical specs of the image, and lens rendering. A lot of things that lead to great images are subjective and preference.
Agreed.. but rarely do people talk about silly things such as subject matter in an equipment forum.
 
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