BEST len Performance ???


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May 27, 2009
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#1
Hey guys i remembered reading an artical about the best performance your lens will give is

when your F stop is 2 to 3 above the minimum F stop of your lens ?
 

ortega

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Nov 2, 2004
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#3
rough guide only

the only way to know your lens
is to test it

manual exposure, set on tripod, constant lighting
shoot using different apertures

then compare and choose the one that you like
 

Rashkae

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Nov 28, 2005
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#4
Depends a lot on the lens itself, really. 80% of lenses will perform their best at f/5.6-f/8

But for large aperture lenses, stopping down by 1-2 stops can already be enough. So an f/1.4 lens could already perform very well at f/2 - f/2.8, and an f/2.8 lens could already be very sharp at f/4, etc etc etc
 

PrimePhotog

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Oct 25, 2007
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#5
Do note that anything beyond f/11 usually decreases IQ due to diffraction in most lenses(not in the case of my Voigtlander 15mm):)
 

giantcanopy

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Feb 11, 2007
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#6
The stopping down 2-3 stops is a general rule of thumb. There are some ( often pricier ) lenses built to be great performers wide open.

But most of the time, I am not really too bothered about that. More often than not aperture would be determined by what u want to shoot and how much dof u require. ( than working around from what the lens is better at )

Ryan
 

Diavonex

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Sep 23, 2008
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#7
Generally the centre of the lens offers the best quality i.e. between f2.8 and f22 go for f8
 

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Rashkae

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Nov 28, 2005
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#8
Generally the centre of the lens offers the best quality i.e. between f2.8 and f22 go for f8
Centre of lens is not the same as aperture. Please go read up a bit more.
 

Diavonex

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Sep 23, 2008
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#9
Centre of lens is not the same as aperture. Please go read up a bit more.
When you open your f -stop to F8, you're actually using the centre of the lens and not the outer circumference. I'm not that dumb.
 

Ouverture

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Jan 19, 2009
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#10
Depends a lot on the lens itself, really. 80% of lenses will perform their best at f/5.6-f/8

But for large aperture lenses, stopping down by 1-2 stops can already be enough. So an f/1.4 lens could already perform very well at f/2 - f/2.8, and an f/2.8 lens could already be very sharp at f/4, etc etc etc
Agree with u bro, it's really like u can only find sweet spot of the lens when stopped down a little, which I wonder why is the case, probably it's manufacturing limitations.

So when we need to use at least F2, then we will have to get a F1.4 lens and if we need a good F4 or so, then minimum is to get a F2.8 lens.

However, some lenses actually are already working at it's best even at max aperture....which is why they are normally very expensive and high in demand...
 

Rashkae

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Nov 28, 2005
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#11
When you open your f -stop to F8, you're actually using the centre of the lens and not the outer circumference. I'm not that dumb.
By that logic, you'd *really* only be using the centre of the lens at f/22. Also, cropped-sensor cameras using a full-frame lens benefit from the sweet spot effect because of aperture rather than the imaging circle (it's not due to aperture btw).

Diffraction plays a part in it too.
 

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