Archived posting to the Leica Users Group, 1997/11/06

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: 35mm/2 light falloff question
From: meino@tfs.com
Date: Thu, 06 Nov 1997 23:09:36 +0100

>>I noticed a different (than expected) result last night when looking at
>>some new proof sheets.  I have a new to me, actually  "preowned", 35mm/2
>>summicron (#35x,xxx , non asp., has notches for lens hood) that I am quite
>>happy with but on the last set of proofs there are several frames with
>>noticable corner vingnetting. I thought of mistakes I could have made. I
>>was using the leica 35mm lens hood and a heliopan uv filter.  I do not
>>think the hood or filter were in the way as most pictures do not have the
>>darker corners.

Every lens has vignetting, However some lenses have more caused by their
construction. It is like looking thru a tube. When the light rays go straigth
thru the tube everyone will pass, but from the rays entering with an angle,
some won't pass. This is where the new ASPH summicron improves much on the
older one. I beleive that the version you own has about 1/2 stop light falloff
in the corner, when used with f2 setting, stopping down the lens will
improve and around f5.6 this should be gone. An other issue is the lenshood.
I own 2 summicrons, one with eyes for my M3 and the same version as you
described. I found out the hardway, that the lenshood I have for the older
35mm summicron (this is the round metal leica lenshood, marked for 35mm and
50mm) can't be used with the newer summicron, because it creates a very
visable corner vignetting.

Meino de Graaf