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Bell & Howell 51mm f/1.2 on A7R ...
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PostPosted: Thu Sep 18, 2014 8:52 am    Post subject: Reply with quote

great results ! #2 and 3 are very good ! looks like your lens is sharper than mine Smile


PostPosted: Thu Sep 18, 2014 9:01 am    Post subject: Reply with quote

Igor wrote:
great results ! #2 and 3 are very good ! looks like your lens is sharper than mine Smile


well, if you had to add contrast and so, there is indeed some difference, because I don't think is needed with my copy. Maybe also interaction with full frame could be an issue?


PostPosted: Fri Sep 19, 2014 8:48 am    Post subject: Reply with quote

Ok, no strange tints Smile


PostPosted: Fri Sep 19, 2014 8:59 am    Post subject: Reply with quote

great bokeh !


PostPosted: Tue Apr 28, 2015 6:18 pm    Post subject: Reply with quote

Guys, I am confused. Received that projector lens (Bell & Howell 51mm f1.2) and can have an image in focus at a distance greater than 20cm if only touch the interior of my NEX-5N with the back glass of the lens. How did you manage to make your images, the great topic starter's portrait, those of children or of the rose, at a distance which seems to be 1.5 meter and more?

Here is a sample with a custom adapter, flange distance at around 30mm:



And here is a sample of the maximum protrusion into the NEX body when the lens barely touches the sensor, so the flange distance is around 3-5mm:



The magenta light "leak" comes from the hole which remains when you insert the lens directly to the body.

How could the flange distance be less than 5mm for a lens destined for 16mm film projection?

Otherwise the image delivered by the lens is a real pleasure.


PostPosted: Tue Apr 28, 2015 6:38 pm    Post subject: Reply with quote

Found another topic about the lens here in the forum: http://forum.mflenses.com/bell-and-howell-2-inch-1-2-projector-lens-t65738.html. But the images in the post must be lost in the last server crash. So your helpful explanations will be highly appreciated!


PostPosted: Tue Apr 28, 2015 7:08 pm    Post subject: Reply with quote

Hi Alex, I don't remember exactly how far was the back element from the A7R sensor, but pretty close for sure. If memory serves me well the max focusing distance was about 1.5m ... that's all I can tell, ... sorry have no idea why your lens doesn't focus further.


PostPosted: Sun Jan 08, 2017 7:37 pm    Post subject: Reply with quote

I noticed a yellow tint to the front element. does anyone know if this lens is thorium coated and hence radioactive? (A good number of wide aperture lenses of the same period were quite radioactive). Thanks


PostPosted: Sun Jan 08, 2017 7:58 pm    Post subject: Reply with quote

madtigerhide wrote:
I noticed a yellow tint to the front element. does anyone know if this lens is thorium coated and hence radioactive? (A good number of wide aperture lenses of the same period were quite radioactive). Thanks


"Thorium coated" does not exist, it was used as an add on to the glass mix to achieve a higher refaction index.


PostPosted: Sun Jan 08, 2017 8:13 pm    Post subject: Reply with quote

Thanks for the technical clarification. Is it radioactive though? Thanks


PostPosted: Sun Jan 08, 2017 8:51 pm    Post subject: Reply with quote

madtigerhide wrote:
Thanks for the technical clarification. Is it radioactive though? Thanks

Bell & Howell apparently used Thorium in their production. There might be a mention of 51/1.2's radioactivity on the net. However, the safest bet is to buy yourself a geiger counter and simply measure it Smile


PostPosted: Sun Jan 08, 2017 11:09 pm    Post subject: Reply with quote

Yeah seems the case from what I read, hoped I could find some golden nuggets of info in here about this specific lens though Smile


PostPosted: Sun Jan 15, 2017 3:16 am    Post subject: Reply with quote

HI all,

Here are two from my copy of the B&H 2 in. F/1.2 shot on a Sony A7II. This is a fun lens!


#1


#2