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Post by belgiumreporter on May 1, 2022 11:03:05 GMT -5
This is going to be a project of wich i don't know how far it'll take me. This Oude Delft 50mm f0.75 is scrapped from a Röntgen machine. It needs such a wide aperture to minimise exposure to radiation when making X-ray recordings. The lens hasn't got a diafragm and focussing helicoid. Because of it's wide aperture the rear lens to film plane distance is only 3mm so as it is it can not be fitted to any kind of 'normal" camera. There's however a few tweaks, by reversing or re-aranging the back lens element group so it can at least be used on a mirrorless body. According to the changes of the back elements a fixed taking distance of 0.3 to 2 meters can be achieved that is either 0,3 or 2 meters, no sliding in between. So this will be waiting on the shelve in the line up of other projects, it looks like in the near future i'll be having some spare time to go about these DIY projects.  |
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Post by raybar on May 2, 2022 7:45:56 GMT -5
Years ago, when I still worked at a camera store, I found a similar lens in a box of junk - - no markings, no diaphragm, unknown f/ stop, unknown focal length, no idea what camera or device it came from. May have been a projector lens.
I mounted it (that is, I taped it to an old lens board) on an equally old 4x5 Speed Graphic, and used the focal plane shutter and a Polaroid back. A few test shots provided an approximate /f number, after which I switched to a roll film back, 120 film being much cheaper per shot than 4x5 Polaroid.
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Post by johnklein94 on May 7, 2022 8:25:19 GMT -5
It is very interesting to wait for the result..
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Post by belgiumreporter on May 8, 2022 6:58:52 GMT -5
So i removed the rear lens elements ((just simply unscrew them, this is not irreversible) and put a M39 adpter (this has the shortest flange to sensor distance) on the Z. I then hand held te lens pressed against the adapter and made these two shots as a proof of concept. This went rather well and from what i see if i could have a 28mm (rear lens thread on the old delft) to M39 adaptor ring this would make for a stable and easy switchable combination on the Z. But now first i'm gonna have some vacation in Kroatia now the covid restrictions are finally lifted  . we'll see the rest when i get back...  
Shots were made at approx 2m distance This is (about) the same shot of the roses (the sun was gone) this time with the Nikkor 55mm 1:1.2 wideopen as you can see there's a significant difference in DOF rendering between 1:1.2 and 0.75. Still these lenses can't be compared, the Nikkor has aworking diafragm and can be focussed at any distance while the Oude Delft will allways have a lot of restrictions.  |
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Post by julio1fer on May 14, 2022 13:47:22 GMT -5
Good to hear that. Make sure you get to Plitvice national park.
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Post by belgiumreporter on May 21, 2022 9:37:05 GMT -5
Good to hear that. Make sure you get to Plitvice national park. Amongst other day trips we went to Plivice and Krka even though controversial we liked Krka a little bit more than Plivice. Plivice:  Krka:  of course there's a whole lot more to see than these two waterfalls but that's not for this topic. |
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. we'll see the rest when i get back...