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joshdaskew
21-Sep-2010, 22:27
Hi, Was just wondering if anyone could tell me what the Image Circle is for this lens? Was wondering if it will cover the Polaroid pack film size of 4.25 x 3.25? I did look at the Schneider website at the 100mm 2.8 Xenotar

https://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses/xenotar/data/2,8-100mm.html

which I have heard has the same lens formula..

When it talks about the image circle diameter at f16 being 117mm, what does this effectively mean? If I planned to shoot wide open with this lens, I presume the image circle becomes a lot less?

So if the pack film is 108mm in width, then should this lens be close to covering it if shot at a wide open aperture?

If you were shooting wide open with 5 x 4 film, what might it look like? Would it just have severe vignetting in the edges or is it a more gradual fade off?

Ok, thanks so much. Cheers josh

Brian Stein
21-Sep-2010, 23:07
1. the xenotar is similar to the planar so I suspect your info is applicable
2. the planar 100/2.8 was made for the linhof 6x9 cameras so will provide coverage and IIRC movement. Also in keeping with 1.
3. the film diameter of pack film is about 135 mm, so any lens with less coverage than this will not cast a sharp image across the entire film area. On older lenses there may be light cast past the 'coverage' area but there is no detail; you may get the whole film illuminated but it will get more 'mushy' the further you go. On more modern lenses there is mechanical vignetting: it will just go black at the edge of coverage. My *guess* is the planar will be of the latter type
4. the image circle in general increases as you stop down, so yes. 6x9 film is about 90mm on the diagonal so your 117 mm leaves nice room for movements on that format.
5. At 108mm you will cover the width, but remember the corners are further way and will not
6. wide open on 4x5: see 3. My guess will be nice sharp round circle of image with black border around. something akin to this http://www.nikonusa.com/kdb/vignetting/vignette_01.jpg.

Peter K
22-Sep-2010, 00:35
Hi, Was just wondering if anyone could tell me what the Image Circle is for this lens?
120mm

When it talks about the image circle diameter at f16 being 117mm, what does this effectively mean? If I planned to shoot wide open with this lens, I presume the image circle becomes a lot less?
With some lenses like Dialytes and WA-lenses from the Biogon-type - often used with LF-cameras - the usable image circle increases with stopping down the lens.

But not with the Planar and similar lenses, if such lenses are stopped down two steps or so the resolution increases but not the image circle.

Emmanuel BIGLER
22-Sep-2010, 06:33
I own one of those 100mm / 2.8 planars and I can confirm that the image circle does not exceed 120 mm. This is only marginally wide than a good ol' tessar of the same focal length.
The lens is a joy to use, focusing on the ground glass wide open at 2.8 is so comfortable !
Well, eventually I also acquired an apo Sironar S 100 / 5.6, that almost covers the 4x5" format..

The collector's suggestion of the day "You Need Both" ;)

joshdaskew
26-Sep-2010, 18:22
Hi, Thanks so much for the reply, greatly appreciated!! Will look at getting one of these as I mainly plan to shoot wide open portraits and therefore don't mind if it gets a mushy towards the edges.... Could be nice maybe. Thanks again, greatly appreciated! Cheers Josh