For years now these industrial super-fast lenses have been on the back of my mind. I am a self described bad photography gear head, obsessing over lens manufacturers and specs, using more time searching for good deals on lenses than actually using them. This is why I always wanted to try adapting these somewhat affordable fast monsters. But one thing always held me back, and that was the fact that most images I could find was frankly uninspiring, boring fuzzy macro shots at best. So I couldn’t justify spending hundreds of dollars on unpractical medical equipment.

One day last year I got the chance to buy two X-ray lenses for around $200 from a local camera entusiast that probably had the same hope as me. This was cheap enough for me to give them a chance and see what I could do with them. The first lens was a Rodenstock XR-Heligon 75mm f/1.1 and the other was a Rodenstock TV-Heligon 50mm f/0.75. I quickly found out that with my Sony A7Rii I could not use the 75mm lens to achieve infinite focus (max 3-4m), this was because this copy had too large of a back element for it to get past the shutter blades. That left me with the 50mm f/0.75. This has a back lens that is tiny, tiny enough to get close enough to the sensor to achieve infinite focus. The problem was to adapt this I had to make an adapter that was not thicker than 4mm, and this without any specialised tools and a low budget. If you think you can free lens this lens, forget about it. You will scratch your outer sensor filters (I am speaking from experience).

At this time I found out that one of the standard 82mm metal lens hoods for tele lenses that can be bought on eBay fit the lens exactly. With this I could make an adapter. Unfortunately there are no one at this point that mass produce step-up rings that are 42-82mm, closest was a 43-82mm. I could combine a 49-82mm step up-ring, 42-49mm step-up ring and then a slim M42 to E-mount. Only problem with this was I could only get to about 2m focus. Not good enough.


My only solution to this was to force the slim M42 adapter and the 43-82mm step up ring to fit each other. This was done by grinding the threading down on each piece. Then I could squeeze these with force to make them fit. I was surprised I didn’t need glue or epoxy, it is only held in place with friction. Believe me I’ve tried to take them apart again, but I simply can’t do it. To achieve infinity focus with this setup I had to remove a small amount (about 1-2mm deep) of aluminium at the end of the lens threading. This was done with hand tools and sandpaper.

The last problem to solve is how do I focus. It could be done either with 3D printed parts to make a basic helicoid, but from previous experience this is not ideal (nor pretty). I noticed that on the 75mm f/1.1 that I could not use had a big threaded piece that was most likely to screw the lens inside the machine it was used on. This could also be used on the 50mm f/0.75. With grinding the diameter down I could easily fit this piece inside the 82mm lens hood, again held in only with friction. Now I had focus and it could do infinite focus. I also wanted an actual lens hood for my lens, but it had no threading on the front of the lens. I used the same method as when making the adapter, with using a shorter reversed 82mm lens hood and some tape to hold it in place. To reverse the threading I used a 86-82mm step down ring. Now I had a good and secure way to add filters of my choosing, a front lens cap and a lens hood.

Below is a visualisation of how i adapted this lens and how it focus:

Rodenstock TV-Heligon 50mm f/0.75 focused to infinity on full-frame. Click on image for a larger preview of the image (7952 × 5304px, 2.2MB)

Lens and camera compatibility issues

Finally I could actually test out the lens. If you are just after the most blurriest bokeh ever, this is not the lens for you. It may be f/0.75, but because the image circle covers only at best APS-C it is more like an 75mm f/1.0. It’s also a tense experience using this heavy beast, I always use a battery grip to have enough room to hold the camera with my hands. But the main drawback is the flange distance. To use this lens you have to shoot in silent mode, this means that the shutter blades don’t move, if they were to move, I would have destroyed my camera in an instant, because the shutter blades would have smashed into the back element. Sometimes when turning off the camera, or it runs out of battery, it may in some cases shut the shutter blades for a “timed” pixel remapping session. That means every time I turn off the camera down there is a slight chance for the shutter blades to fire. I wish there was a way to disable this feature, but after consulting with some other Sony A7Rii users I found out that it’s not possible. The only solution I could find was that you could force a pixel remapping session to take place. This is done with changing the date 1 month forwards. So every time I go out with this lens, I force this to session to occur. This gives me a bit of peace of mind, but there is always a slight chance it will fire the shutter. So because of this when I want to turn off the camera I focus as close to minimum focus distance as the lens lets me. this makes the back optics move to a more secure position, hopefully enough to be a safe distance from the shutter blades. One other small thing to note is that to dismount this lens I have to use a tool of some kind to push down the lens release knob on my camera, there is not room for fingers between them.

Lens characteristics

As you might have guessed from the text above, this is not an easy lens to handle. It doesn’t help that the actual focus plane is wafer-thin. But this is not the biggest issue if you are used to shooting manual and with the benefits of a digital viewfinder to get a 1:1 zoom off the final shot.
After using this lens for a good month, I am still perplexed about the lens characteristics. One thing I am fairly certain of is that the lens is sharpest when the subject is more 1.5-5m away from the camera. anything less than 1.5m will become very unsharp and makes highlights glow. This is quite funny when thinking about almost all other images I could find that people have taken with lenses like these are in the extreme macro range. No wonder why I and other people think of these lenses as a piece of garbage. When you actually get going, it is just like any other lens I’ve used.

The edges of the images will never be in focus, this seems to be a design feature as I think these parts of the image circle were never meant to be used. I suspect the actual format this lens should shoot at is MFT or smaller. It gives a weird circular effect, not like swirly bokeh, something completely different. It reminds me of some of the images taken with old Helios-44-2 lenses with the back elements reversed, only the Rodenstock is sharper in that regard. In some shots the bokeh is more bubbly, almost like one of those mirror telephoto lenses.

For those people who are wondering how this lens performs at low light, it’s about the same as any other fast lens, nothing ground breaking. You still have to bump up the ISO, just a bit less than normal. With this I mean there is little benefit to buy a f/0.75 lens for its low-light capabilities alone. As this is said, I am no expert in optics, so I don’t know how to measure the T-stops, maybe the actual T-stop number is far less impressive than the F-stop number.

If you have some advice, information, requests or questions about this lens please don’t hesitate to contact me, I want to learn more.

In conclusion

I will most likely never learn to understand the lens, but that kinda makes it more fun to use, I will never quite know how the final results will be. All in all it is totally impractical, hard and sometimes stressful to operate. But there is something that draws me back to it, maybe it is a sense of discovery and fascination that this industrial lens can actually be used.


  • Light sensitive
  • Fun


  • Big and heavy
  • Flange range too short for comfort
  • Focusing is awkward
  • APS-C image circle at best
  • Inconsistent performance

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