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Forums > Back > From da lab ...
#11
Decisions decisions... 8-)
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#12
Just for the fun of it

Vignetting of the 16-55mm f/2.8 @ 16mm - WITHOUT any correction:
f/2.8: 9.67
f/8: 6.71
Chief Editor - opticallimits.com

Doing all things Canon, MFT, Sony and Fuji
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#13
(06-14-2021, 11:06 AM)Klaus Wrote: Just for the fun of it

Vignetting of the 16-55mm f/2.8 @ 16mm - WITHOUT any correction:
f/2.8: 9.67
f/8: 6.71

f/2.8:  .......... 9.67

f/8:    .......... 6.71  

what, stops ?
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#14
Yes, of course.

In all fairness - if one accepts, that this lens just isn't meant for getting used without auto-correction, it is actually very good. The samples are impressive actually.
Within this context, it's probably the best APS-C standard zoom lens there is.

The vignetting figures are only so bizarrely high because of the image distortions.

It's the same with the Canon RF 24-105mm f/4-7.1 STM IS (except that this one is a coke bottle)


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Chief Editor - opticallimits.com

Doing all things Canon, MFT, Sony and Fuji
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#15
Yeah, show us the coke bottle review sometime!..
Good that I'm a Pepsi guy btw, else I would've taken issue with the choice of bottle to represent it. Smile
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#16
(06-14-2021, 11:06 AM)Klaus Wrote: Just for the fun of it

Vignetting of the 16-55mm f/2.8 @ 16mm - WITHOUT any correction:
f/2.8: 9.67
f/8: 6.71

those are just numbers, what corrects vignetting mostly is dsitortions correction not vignetting correction per se, those too dark areas will be simply cropped out
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#17
Are those numbers on full frame or aspc ? I mean what is the point of having f2.8 if vignetting is nearly 10 stops ?
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#18
(06-15-2021, 11:56 AM)you2 Wrote: Are those numbers on full frame or aspc ? I mean what is the point of having f2.8 if vignetting is nearly 10 stops ?

It is neither, basically. It is an APS-C lens, that is very undercorrected at 16mm. It is nearly 10 stops when you measure the corners that are supposed to be discarded anyway (by correcting the distortion in camera or in RAW conversion).

That the lens is f2.8 wide open has little to do with this. When corrected for distortion, it still is f2.8 at 16mm.
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#19
I wonder what sensor area is left and how many Mps the image is after these corrections ???

looking at the vignetting and distortion figures, quite lot seems to be chopped off !!
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#20
The corners have excess FOV, the horizontal and vertical center lines do not. The corners get stretched and the excess gets chopped off, leaving you with the same megapixels you started with. Just with lower sharpness in the stretched areas.
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