Hi Michael,
I downloaded the photo and used the eyedropper in Photoshop to check the
color values at the top of the image.
Top Left:0 6 52 Top Center:0 15 74 Top Right:0 3 48
I think it is the expected light fall off of the lens imposed over a not
exactly uniform sky. The bright white cloud probably makes the left side
both brighter and seem even brighter. Even within the specified IC there is
light fall off. As mentioned by Wayne, the bottom of the photo has light
concrete which exaggerates the difference.
The IC specification is often a soft limit. It may be specified because of
either reduced resolution and/or light reduction. It is also specified at a
specific aperture. Stopping down further improves the vignetting for some
but not all lenses (G-Claron is the one the many stop down and use way
beyond the specified IC).
The center filters are expensive but they do show up on ebay from time to
time. Some LF people actually prefer to have some soft vignetting and don't
correct it. My personal preference is revealed by ebay 250677002916. Black
and White users are less likely to want a CF.
Best wishes,
Jeff
-----Original Message-----
From: Michael Wong [mailto:mialop@xxxxxxxxxxxx]
Sent: Sunday, August 15, 2010 9:29 AM
To: Olympus Camera Discussion
Subject: Re: [OM] Visited Macau
Jeff,
I understood but I don't know why vignetting at right upper corner only.
According information from largeformatphotography.info, the max rise of 72XL
is 47.75mm
http://www.largeformatphotography.info/lenses/LF4x5in.html
My Ebony SW45 can be rised max 60mm, I'm not sure did I rise the front panel
near the limitation of 72XL caused vignetting?
Maybe I have make a mark at my camera to remind me the max rise for 72XL.
---
Michael
On 15 August 2010 15:14, Jeff Keller <om-list@xxxxxxxxxxx> wrote:
> Hi Michael,
>
> I don't know if you've come across this: many LF cameras have the corners
> of
> the focus screen clipped off so that when everything is set up including
> the
> aperture stopped down you can look through the corners to see if the
> aperture is round. If your focus screen has clipped corners you should be
> able to see any mechanical vignetting show up as a football shaped
> aperture.
>
> The Super Symmar XL's are thought to have the greatest light falloff but
> the
> IC on your 110 SS XL is so large you shouldn't have a problem with it. The
> 80mm SS XL had a recent discussion:
>
>
http://www.largeformatphotography.info/forum/showthread.php?t=65234&highligh
>
t=center+filter<http://www.largeformatphotography.info/forum/showthread.php?
t=65234&highligh%0At=center+filter>
>
> The Schneider center filter for the 72mm XL has a 112mm front filter
thread
> so that a second filter could be attached to it and not cause vignetting.
> The lens has a 95mm thread which they surely believe is fine for a single
> filter. The lens has a 226mm IC and would thus cover a 5x7 film with
little
> room left for shift/tilt.
>
> The Super Angulon 90mm f8 has a IC of 216mm so it can handle about an inch
> of shift from center.
>
>
http://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses/su
>
per-angulon/data/8-90mm.html<http://www.schneideroptics.com/info/vintage_len
s_data/large_format_lenses/su%0Aper-angulon/data/8-90mm.html>
>
> The schneideroptics website has a lot of information but finding it seems
> to
> require a search engine.
>
> Best wishes,
> Jeff
>
> -----Original Message-----
> From: Michael Wong [mailto:mialop@xxxxxxxxxxxx]
> Sent: Saturday, August 14, 2010 7:46 PM
> To: Olympus Camera Discussion
> Subject: Re: [OM] Visited Macau
>
> I have same experience for my old Super Angulon 90mm F8, is the vignetting
> easy to perform for wide angle lens?
>
>
> Thanks, Jeff.
>
>
> ---
> Michael
>
>
>
> --
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>
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