Smaller aperture=better image quality??


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redmonsoon

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#1
Just read this statement somewhere, can anyone comment if its valid?Thks.

>the smaller aperture (bigger F number) the better image quality will have.
 

redmonsoon

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#4
Yes, I understand abt stepping down 1-2 stops.
But, not say with all other factors considered same, f16 is going to be sharper than f2.8 right?
 

catchlights

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#5
each lens has a sweet spot, it have better sharpness from corner to corner, evenness of light distribution, etc.... usually at two ~three stops down from maximum aperture.

hence it is correct to say smaller aperture will get better image quality, however, smaller aperture ≠ minimum aperture, cos deflection will kick in beyond f22
 

Kit

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#7
Many people got confused with sharpness and depth of field. Deeper depth of field with smaller aperture means more portion of the image will be in focus but that does not means the image is sharper, just that the details are clearer delineated.
 

ahbian

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#8
Perhaps, if you are thinking that some lens have CA if not stopped down.
 

redmonsoon

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#9
I think can safely conclude Smaller aperture DOES NOT EQUAL better image quality.

>each lens has a sweet spot, it have better sharpness from corner to corner, evenness of light distribution, etc.... usually at two ~three stops down from maximum aperture.

The reason for my posting is because I'm concerned of seeing wrong teachings on CS and noobs absorbing wholesale, wasting their own time.

I also noob thats why when I saw this statement I scour online but cannot find anything to support it, so ask here. I suggest other noob shd also research online yourself for more info. :) hee.

*""There is no need to say setup tripod, step down to F16, shutter 5sec, to get 'better' image quality", thats flawed.:)
 

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cks2k2

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#10
each lens has a sweet spot, it have better sharpness from corner to corner, evenness of light distribution, etc.... usually at two ~three stops down from maximum aperture.

hence it is correct to say smaller aperture will get better image quality, however, smaller aperture ≠ minimum aperture, cos deflection will kick in beyond f22
Not deflection, but diffraction.
 

catchlights

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#12
I think can safely conclude Smaller aperture DOES NOT EQUAL better image quality.

>each lens has a sweet spot, it have better sharpness from corner to corner, evenness of light distribution, etc.... usually at two ~three stops down from maximum aperture.

The reason for my posting is because I'm concerned of seeing wrong teachings on CS and noobs absorbing wholesale, wasting their own time.

I also noob thats why when I saw this statement I scour online but cannot find anything to support it, so ask here. I suggest other noob shd also research online yourself for more info. :) hee.

*""There is no need to say setup tripod, step down to F16, shutter 5sec, to get 'better' image quality", thats flawed.:)
Google "lens", "sweetspot" you will find the answers to your question.
 

gnohz

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#14
As a general guide, maybe you would want to use the lens from around 5.6 to 11 and not going more than 16 for best results, but it differs from lens to lens :)
That said, many lens perform badly when they're wide open (maximum aperture) since that's normally not their sweet spot.
 

redmonsoon

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#15
With regards to stepping down..

QN: Would you rather UP ISO to step down, or Wide Open with lower ISO?

Hmm, ok, tink I know the answer is, depends...lol:bsmilie:
 

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#17
There are some cases whereby a lens has to be "optimized" for a certain f-stop range.

E.g. - The ZM Sonnar f1.5 which is optimized for either f1.5 performance or f8 performance by the Zeiss factory. Hardcore lovers of this lens will get two copies, each optimized at different f-stops ;p I hear that the difference in sharpness can be quite alot, but i don't have one for myself to try :dunno: Therefore, higher f-stop, or even f8 f-stop is not alwys better.
 

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