[Leica] My first problem with Vignetting

[henningw at archiphoto.com (Henning Wulff)]

>Thanks Henning.... I am going to try the back way first......
>
>BTW, this vignetting as around 1/8 inch in from the corners, and it is
>totally unexposed.  It is not subtle.
>
>Frank Filippone
>red735i@earthlink.net
>
>Opening the back and looking through the corners with the shutter
>open is a lot more accurate, besides being cheaper and faster, than
>taking shots.
>

That's a hood or whatever blocking the rays to the corners. Easily 
seen when opening the back and looking through the corners. If no 
light gets through the corners even when the lens is stopped down to 
f/8, that'll translate into the effect you've seen.

BTW, this test is very easy, and totally correct, so if you find a 
hood that seems to fit on your lens and you're concerned about the 
vignetting issue, you can check it on the spot in about a minute if 
you have a body without film. Check first without the hood to see how 
it should look, and then with the hood on.

Best is to point your camera at a bright surface (not point source, 
as that can obviously mislead you) and angle your camera more and 
more until you are looking right through the corners of the frame.

Checking for vignetting on an SLR, by looking from the front through 
the lens to see if light passes from the corners of the viewfinder 
without being blocked by the hood is not as correct, as the area 
shown by the SLR viewfinder is seldom 100% accurate, and the whole 
thing is a lot harder to see.

-- 
    *            Henning J. Wulff
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