Author Topic: Projection lenses (Read 148131 times)

koondr · « **Reply #375 on:** October 20, 2019, 12:27:46 »

Quote from: Toby on October 20, 2019, 11:55:21

Hi koondr--
Great look with the XR Heligon. What camera are you using? My XR Heligon (90mm) seems to have a much shorter flange distance than yours.

Sony A7

Toby · « **Reply #376 on:** October 21, 2019, 09:18:27 »

Thanks!

Drone004 · « **Reply #377 on:** November 30, 2019, 16:26:41 »

Esteemed Forum members,

This is my first post here, and I am starting by asking for some help.

I recently procured two lenses which are not exactly Projection lenses but produce similar results. Given the very obvious experience and expertise so many of you have shown in so many images and posts, I'd like to ask for the following:

Does anyone have any experience adapting and/or having the specifications (esp. screw mount size/thread) for these two:

Rodenstock TV Heligon 64 f0.95

and

Wollensack Oscillo Raptar 75 f1.9

I'd like to ideally adapt them both to M42 so that I can exchange them between my medium format, full-frame, and cropped sensor cameras. I do suspect that both lenses will likely fully cover only the cropped sensor, for sure.

Thank you very much in advance, and have a wonderful weekend!

Toby · « **Reply #378 on:** November 30, 2019, 22:35:51 »

I can counsel you on the Oscillo Raptar. My way of mounting was to wrap some PVC electrician's tape around the rear barrel of the lens, so that it fits snugly inside a M52 to M42 helicoid (25-55mm). This allows infinity to very close focus on a mirrorless camera. I also wrapped a bit more tape around the front barrel (it is slightly smaller diameter) so that I could use the lens reversed in the same helicoid. Reversing the lens exaggerates the bokeh. The Oscillo Raptar has a curved field, so it is not really useful as a general purpose lens, but it has nice bokeh. Stopping down to f2.8 increases contrast and reduces highlight glow, with still very characteristic bokeh.

If you are trying to adapt to a DSLR you will not be able to focus to infinity. Even holding the lens directly on the mount of my previous Nikon D800, maximum distance was about 20cm from the lens. Reversing the lens gave me slightly more distance. I believe that the flange distance of the lens is about 30mm. Below is an example with the lens normal, the second with the lens reversed wide open, the third with lens reversed stopped down to f3.5.

The Raptar will most definitely cover FF. It may also almost cover MF, but the corners will be extremely soft.

golunvolo · « **Reply #379 on:** November 30, 2019, 23:11:17 »

Love specially the overall ambiance in the first image of your last post. Beautiful mystery.

Birna Rørslett · « **Reply #380 on:** December 01, 2019, 12:03:55 »

The general approach to modifying the Heligons is getting suitable threads, for most lenses that means 52mm threads at least. Most of my Heligons allow a 52mm Cokin-type adapter or similar to be located at their rear end, pushing against a wider flange further down on the lens casing. Either fix the ring containing threads by epoxy glue, or small screws if possible. From this thread, preferably of the female variety, one can add extension tubes and then any kind of lens mount adapter at the very end. I'm fond of using the ancient K-ring sets for this purpose.

With the 100mm f/1.6 XR-Heligon, I also have the option of mounting it into a 65mm helicoid for use on my Z cameras. Mounted in this manner it easily reaches infinity.

Frank Fremerey · « **Reply #381 on:** December 01, 2019, 20:46:42 »

@Toby... the Raptar shots are hypnotic, what a gift

Toby · « **Reply #382 on:** December 01, 2019, 22:27:21 »

Quote from: Frank Fremerey on December 01, 2019, 20:46:42

@Toby... the Raptar shots are hypnotic, what a gift

Thanks Frank. It was my first real "bokeh" lens. It is a bit over the top for some things, but it works well sometimes. Here are a couple more I like.

Akira · « **Reply #383 on:** December 01, 2019, 22:34:21 »

All looks beautiful, Toby. The butterfly shot is superb!

Dr Klaus Schmitt · « **Reply #384 on:** December 04, 2019, 06:24:02 »

Congrats Toby, indeed some great shots!!

Toby · « **Reply #385 on:** December 04, 2019, 12:25:00 »

Thanks guys!

Toby · « **Reply #386 on:** January 10, 2020, 17:01:39 »

Hi folks,
I just received a rather strange old projection lens, an Astro Nitor 105mm. From the look of it, it should be a standard Petzval, but the look is quite different from other Petzvals that I have. Here are some first shots from it, and looking forward to playing more with it in the next days. The lens is completely uncoated, and flares very easily, with low contrast at the best of times, so these shots have been adjusted for contrast, sharpened and optimized according to my eye.