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+--- Thread: Make your guess ... (/showthread.php?tid=1813)
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Make your guess ... - Klaus - 07-18-2013
Ok, Ok, I apologize to all Sony 16-50mm OSS users beforehand. :-)
Anyway, the challenge is: estimate the native vignetting in terms of f-stops:
![[Image: vig16mmf35.jpg]](http://www.opticallimits.com/images/8Reviews/lenses/sony_1650_3556/vig16mmf35.jpg)
To be fair - the lens is really meant to be used with distortion correction. In this case it looks like this (2.1 f-stops). This is RAW converted - the above is a straight JPEG.
![[Image: vig16mmf35corr.jpg]](http://www.opticallimits.com/images/8Reviews/lenses/sony_1650_3556/vig16mmf35corr.jpg)
Make your guess ... - marco - 07-18-2013
Do you applied vignetting correction too or is it only distortion correction?
Make your guess ... - Klaus - 07-18-2013
The 2nd image had distortion correction applied only. Nothing else.
Thus you can see that the dark edges are basically pushed/stretched beyond the image field.
The inner zone is interpolated accordingly (obviously not visible here).
Make your guess ... - Guest - 07-18-2013
Yikes. looks at least 4 stops, probably difficult to measure really accurately in 8 bit. 4.2?
Make your guess ... - Guest - 07-18-2013
I don't know the answer but it isn't going to be pretty.
Make your guess ... - Klaus - 07-18-2013
FWIW, at f/11 things look sort of funny ...
![[Image: vig16mmf11.jpg]](http://www.opticallimits.com/images/8Reviews/lenses/sony_1650_3556/vig16mmf11.jpg)
Make your guess ... - Klaus - 07-18-2013
Quote:yikes. looks at least 4 stops, probably difficult to measure really accurately in 8 bit. 4.2?
Now that you mention this ... seems as if the Imatest result is erroneous.
Make your guess ... - dave9t5 - 07-18-2013
Are yo able to ascertain if, after distortion correction, the corrected image from the lens has the FOV of a rectilinear 16mm lens, or is it less?
Make your guess ... - Guest - 07-18-2013
Quote:FWIW, at f/11 things look sort of funny ...
I guess they forgot to remove the Non-slim UV filter, and there is mechanical vignetting ...
Make your guess ... - Brightcolours - 07-18-2013
Quote:Are yo able to ascertain if, after distortion correction, the corrected image from the lens has the FOV of a rectilinear 16mm lens, or is it less?That is always the case.. Under-corrected lenses show a wider FOV than well corrected lenses (same with the 14mm from Samyang, for instance). So in that sense, you do not lose anything when you correct in post processing. But you do lose in image resolution.