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chalky
Joined: 10 Jun 2014 Posts: 14 Location: cornwall, UK
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Posted: Tue Jul 21, 2015 9:09 am Post subject: Pentac / dallmeyer / air ministry 8" cleaning |
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Hi all,
I have searched here and google but haven't found anything, but if this is a duplicate please let me know.
I have an 8" f2.9 aerial lens, made I think by air ministry, it was cheap ish but there is some haze between the front elements. I can remove all the front elements from the barrel but have no idea how to separate them to clean the inside.
I know these are of varying quality, and the lens works, with nice highlight blur etc but it is slightly soft and I am wondering if this is just one of the poorer lenses or the haze is impacting?
Any thoughts or does anyone know how to take this lens apart?
Many thanks,
Matt _________________ http://www.flickr.com/photos/mattchalkysmith |
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Dan Fromm
Joined: 14 May 2001 Posts: 2144 Location: New Jersey
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Posted: Tue Jul 21, 2015 12:40 pm Post subject: |
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You'll get a better answer if you ask on http://www.largeformatphotography.info/forum/
Here's a lousy answer. I've taken a few Dallmeyer lenses apart. They just unscrewed. I've never tried to unscrew a Pentac so have no idea of how they went together.
The Pentac has five elements in three groups. The outer groups are cemented doublets, the inner group is a singlet. If you've removed the outer groups from the barrel you've done all that's possible without uncementing the doublets.
The Air Ministry was the customer, bought the lens, didn't make it. |
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chalky
Joined: 10 Jun 2014 Posts: 14 Location: cornwall, UK
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Posted: Tue Jul 21, 2015 1:41 pm Post subject: |
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Hi Dan - thanks for the response and also for clearing up about the manufacturer... I have no idea if pentac or dallmeyer made mine but will research further and see what I come up with and if it makes a difference.
I've posted over on the other site and will report back if I get a useful response.
I have managed to unscrew the front and rear sets from the barrel, so it sounds like I am out of luck. There is a small grub screw but removing it doesn't seem to do much.
cheers
Matt _________________ http://www.flickr.com/photos/mattchalkysmith |
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