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JML 64mm f/0.85 Full Frame lens
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PostPosted: Sat Nov 07, 2015 8:13 am    Post subject: JML 64mm f/0.85 Full Frame lens Reply with quote

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Last edited by Opticus on Sun Aug 21, 2016 7:22 pm; edited 1 time in total


PostPosted: Sat Nov 07, 2015 8:57 am    Post subject: Reply with quote

x-ray lens has very short FFD and they are usually super fast.


PostPosted: Sat Nov 07, 2015 9:19 am    Post subject: Reply with quote

It will be for capturing the image on a low intensity CRT, which means it is likely from an X-ray system.

Back focus on the Rodenstock XR and TV Heligons is 6-7mm, so this one is probably similar, hence no infinity on an A7.


PostPosted: Sat Nov 07, 2015 10:29 am    Post subject: Reply with quote

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Last edited by Opticus on Sun Aug 21, 2016 7:23 pm; edited 1 time in total


PostPosted: Sat Nov 07, 2015 12:34 pm    Post subject: Reply with quote

Can you not shave a bit off the bottom of the housing?


PostPosted: Sat Nov 07, 2015 4:34 pm    Post subject: Reply with quote

Many lenses at extreme close-up will cover ff. Coverage should be checked at infinity.
I was trying some 8mm cine lenses once, mounted on PK lens caps, and they covered both APS-C and FF. Of course, they would only focus extremely close.


PostPosted: Sun Nov 08, 2015 9:17 am    Post subject: Reply with quote

Saw that on enay a few days ago....

Xray lens


PostPosted: Sun Nov 08, 2015 10:43 am    Post subject: Reply with quote

Perhaps rear condenser was taken off thus the bigger projected image.


PostPosted: Sun Nov 08, 2015 10:54 am    Post subject: Reply with quote

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Last edited by Opticus on Sun Aug 21, 2016 7:23 pm; edited 1 time in total


PostPosted: Sun Nov 08, 2015 10:58 am    Post subject: Reply with quote

Looks very nice and the large image circle is great!!


PostPosted: Sun Nov 08, 2015 12:03 pm    Post subject: Reply with quote

Don't modify the A7, you might destroy it, certainly you will destroy it's value.

You can place a negative dioptre in front of the lens to increase the rear focal distance.


PostPosted: Sun Nov 08, 2015 12:23 pm    Post subject: Reply with quote

Thanks for the tip. Does a negative dioptre affect image quality much?


PostPosted: Sun Nov 08, 2015 12:31 pm    Post subject: Reply with quote

It might introduce CA. BUt the lens has much of it anyway....
The cost of such a large one might be considerable and not easy to find.
Negantive diopters are rather rare.


PostPosted: Sun Nov 08, 2015 2:36 pm    Post subject: Reply with quote

First of all, check the lens for radiation!!!


PostPosted: Sun Nov 08, 2015 6:24 pm    Post subject: Reply with quote

I successfully added a -3 diopter to the front of a Cine-Xenon and it hasn't degraded the IQ in any way that I can discern.



I found the diopter on ebay, 50mm diameter, in the Scientific category are lots of different types of lenses:

http://www.ebay.co.uk/itm/Double-concave-lens-50mm-x-200mm-focal-Length-Magnifying-Negative-or-Diverging-/321305459373?hash=item4acf4c3aad:m:mLsd2g9OkVMN_KQYehqKHMg

Larger ones can be tricky to find, but this place is likely to have something suitable:

surplusshed.com