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Re: [OM] Visited Macau

Subject: Re: [OM] Visited Macau
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Mon, 16 Aug 2010 08:25:02 -0400
You shouldn't have any need for a circular polarizer on a view camera. 
A linear polarizer should work just fine, be cheaper and, I think, 
somewhat more effective.

Chuck Norcutt


Michael Wong wrote:
> Thank you very much, Jeff.
> 
> I understood I should put CF on the wide angle lens to avoid fall off but as
> you said, it's very expensive. But I think I'll go to get one finally.
> 
> Btw, I searched internet & found the website for Schneider large format lens
> information:
> https://www.schneideroptics.com/ecommerce/CatalogSubCategoryDisplay.aspx?CID=162
> 
> But it seems not many information provided. Such as what size of CPL to be
> applied to 72XL ............ or what kind of CF to to applied  ......
> Is any good website with more information provided? Thanks.
> 
> 
> ---
> Michael
> 
> 
> 
> 
> On 16 August 2010 01:11, Jeff Keller <om-list@xxxxxxxxxxx> wrote:
> 
>> 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<http://www.largeformatphotography.info/forum/showthread.php?%0At=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<http://www.schneideroptics.com/info/vintage_len%0As_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
>>>
>>>
>>>
>>> --
>>> _________________________________________________________________
>>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
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>>>
>> --
>> _________________________________________________________________
>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
>> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
>> Themed Olympus Photo Exhibition: http://www.tope.nl/
>>
>>
>>
>> --
>> _________________________________________________________________
>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
>> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
>> Themed Olympus Photo Exhibition: http://www.tope.nl/
>>
>>
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