NikonGear'23
Gear Talk => What the Nerds Do => Topic started by: Birna Rørslett on February 20, 2023, 10:55:11
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More than two decades ago, in my former existence, I wrote an article entitled 'Need for Speed' on the ancient naturfotograf.com website. This piqued the interest of many people to use, or more precisely, abuse - old optics used on X-ray machines and similar. Brand names such as Rodenstock TV-Heligon or De Oude Delft Rayxar became familiar to a wider circle of enthusiasts. And prices on eBay soared accordingly.
There industrial lenses had a common factor, viz. rather unheard of "speed" with exotic apertures of f/0.7, 0.75, 0.8, ... Real speed monsters they were? Or no, as the nominal f-number figure N of a lens refers to infinity focus. However, these lenses all had huge font size and a tiny rear element, leading to a small pupil factor P
P=[size of exit pupil]/[size of entrance pupil])
again leading to larger f-numbers N' when the lens is focused closer to give magnification m
N' = N*(1 + m/P)
Now, in their designated position, the "X-Ray" lenses were used as a tandem pair with each lens at infinity focus, so the attained "speed" really was awesome and the f/0.75 etc. manifested.
The Rodenstock TV-Heligon 50mm f/0.75, a widely used lens in its time, quickly was pooed upon as yielding very soft and low contrast images of a blurred nature. As this deviant rendition was its raison d'etre for photographers seeking an alternative to the increasingly perfect rendition of modern optics, the hard-core experimenters soldiered on with their adapted glass heavyweights for years, until the speed craze petered slowly out.
Now, if image quality was abysmal, why were those lenses used in the first place? Obviously the photographers abused the optics in a non-designated manner, and because infinity focus could not be reached, never observed the potential quality of the Rodenstocks or Rayxars.
The SLR or DSLR principle of former days lead to a long back focal distance, ie. the distance from the lens mounting flange to the film or sensor. With the arrival of mirrorless cameras, the potential of mounting lenses closer to the recording surface became a reality. Still, the sheer physical size of the "X-Ray" optics was an obstacle not easy to overcome.
Enter the Sony E-mount (register 18mm) and Nikon Z (register 16mm). In particular the Z system, with its very wide throat, opened up a new avenue of possibilities. Even more so the arrival of the shutterless Nikon Z9!! As the back distance for infinity focus for such optics are generally < 10mm, some even as short as 3-4mm, not having a shutter in conflict with the rear part of the lens is a big bonus. So when I got my Z9, plans for adapting my exotic lenses immediately were drawn up. Real life then bit back with a nasty Covid-19 infection thus we need to fast forward approx. 1 year to see the idea in fruition.
Here is a demonstration of the inherent quality of the Rodenstock TV-Heligon at a focused distance of approx. 100m. Consider this was at an effective aperture f/0.75, the quality is really surprisingly good for a lens more than 50 years old !! This is on the Z9. Right-click to open the image in a separate tab to reach 100%.
Read on to learn how this feat was achieved.
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To satisfy readers' curiosity, here is a quick run-down on how I adapted my Rodenstock (or Rayxar) to infinity focus. Both lenses use the same adapter
First, the parts. The lens (Rayxar 50/0.75), the mounting flange for the lens (approx. 80mm thread inside), a 52-77 step ring, and a flat and ultra-thin M42-Z adapter. I got the mounting gear as part of the lenses at the time of purchase.
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The step ring sits inside, with some trimming.
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Using my Dremel, the step ring is trimmed to be flat, ready for the Z mount. I secured the M42-Z adapter with a counter-thread slim plate on the inside (poked out from a full-size M42-Z adapter by Pixco if memory serves). This last precaution is not really necessary as the oven-cured epoxy glue will hold the mount in place, but one can never be safe enough I presume?
That's all there is to the adaptation. Focusing to infinity now is a breeze. The full "speed" f/0.75 is manifested.
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And finally, the adapted Rodenstock 50mm f/0.75 lens on my Nikon Z9, seen against Tatiana's beautiful handcrafted runner. I have made a make-shift lens hood for the lens as well, however aim to have it replaced by a properly fitted 86mm hood once the ordered parts arrive.
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Thank you for sharing your Speed Solution for Z mount! The results speaks for themselves - Marvelous 8)
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Thanks to you as well, Master Erik. I have silently watched your deft workmanship up close so many times that some of the experiences have rubbed off :)
At present I seriously consider getting a low-end camera like the Nikon Z30 and have it modified for use with the X-ray lenses. It would need internal changes to allow the rear part of these lenses to be seated close enough to the sensor surface. A cover frame around the sensor will block access. Once this is trimmed off, the lens should work effortlessly even on this camera. There is a shutter curtain on the Z30, but that ought not to cause problems as the Rodenstock etc. works well on the Z6/7 bodies, the latter also having shutter curtains.
With the Z/DX, nearly all of the sensor surface may be used. However, the overhang of the finder of my Z fc prevents the chosen adapter from being mounted. Hence the idea of using the modest Z30 for my X-Ray optics.
Maybe a spring visit to Copenhagen would be possible?
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Great article Birna. And thanks for showing the adapter.
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I was lucky that I kept the mounting brackets accompanying these lenses at the time of purchase. They typically were offered on eBay etc. as spare parts or lab surplus, and sometimes rather comprehensive mounts followed with the lens. No idea of the present situation, but I presume it cannot be too difficult to find similar parts even today.
I will use a second mounting flange for a bespoke adapter for the Rayxar, as this lens needs to be seated a tad closer than the Rodenstock. I also have a Kowa 55mm f/0.8 that might require a short back focus distance (using the same thread).
An infinity focusing adapter for the Rodenstock 100mm f/1.6 was made several years ago, when I got my first Z camera. This lens is very easy to adapt as the rear focal distance is much longer, around 35mm if memory serves. The projected image circle of the 100/1.6 covers the FX format but one should cut down a few mm in the extreme corners for infinity shots, as they may be a little soft. That lens is superb for IR photography as well.
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Great and successful project!
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Looks amazing and ready for fun.
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Impressive result, both mechanically and technical pictorial quality.
When I first encountered such a thick monster I was impressed by its f-number and at its ca 10USD price, it could not be left behind.
p.
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I have read up on the more technical descriptions of these lenses, and the differences noted earlier are confirmed. According to this informative Italian web site
http://www.marcocavina.com/articoli_fotografici/Rodenstock_De_Oude_f_0,75/00_pag.htm
the back focus for the TV-Heligon 50/0.75 is 6.1mm. Thus, no wonder my adapter allows infinity focus -- and beyond -- for the Heligon, as it can seat the lens down to approx 3mm away from the sensor surface. I can easily observe the treeline on the horizon coming into focus when I focus "closer".
For the Oude Delft 50mm f/0.75 Rayxar, the back focus is given as 0.8mm. My current adapter cannot produce this short distance so "infinity" at present is approx. 75m with the Rayxar. An example is provided below. The image quality if anything is even better than for the TV-Heligon, however the danger of scratching the sensor surface is so high I now think that say a cheaper Z30 should host this lens instead of the Z9.
Anyway, the evidence that the Rayxar can deliver very fine quality at distance,
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Rodenstock TV-Heligon 50mm f/0.75 can now easily do infinity focus. The hill side on the opposite side of "my" river valley is approx. 5km away and serves as my test object. I needed in fact to focus closer in order to get the hillside into focus.
Centre of frame on Z9, 100%. Exposure dropped perilously close to the 1/32000 sec limit of the Z9 thus I had to dial in a negative EV correction to handle the situation. The "X-ray" class of f/0.75 lenses are ill suited for photography in bright sunshine, unless one adds a dense filter :)
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Action photography by the Rodenstock TV-Heligon early this morning. The ultrafast lens helped give barely adequate shutter speed :)
(https://nikongear.net/revival/index.php?action=dlattach;topic=10619.0;attach=56962;image)
The lens in its current adapter has "unit" focusing, and as the thread pitch is fine, manual focusing is pretty slow. Still doable and this opens new avenues to explore.
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The Oude Delft Rayxar 50/0.75 at its current "infinity" position [max. 75m due to the limitations of the adapter used] will render more distant scenes pleasantly blurred by its delicate bokeh. This night snowfall scene had strong wind, lots of snow in the air, so an overall blurring manifested itself anyway. Focus is on the Scots Pine in the foreground, distance about 60m.
(https://nikongear.net/revival/index.php?action=dlattach;topic=10619.0;attach=56901;image)
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Ideal for decorating dinner plates
p.
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I'm enjoying your crystal ball shots, Birna. :)
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The Mk.2 version of the infinity-focusing adapter is now completed. It indeed allows infinity focus also for the demanding Oude Delft 50mm f/0.75 Rayxar. Caveat: not [yet] on the Z30, because of the wide rear component of this lens. Or should I say, not until Erik the Great has had his hands on the Z30.... For the Rodenstock 50/0.75, the tiny Z30 does not complain too much and focus reaches to infinity as well.
The "X-ray" lenses completely dwarf the little Z30 :)
(https://nikongear.net/revival/index.php?action=dlattach;topic=10638.0;attach=57021;image)
The fit is very tight, but by sheer serendipity the adapter fits. For more details, read on.
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Basically the new adapter is the old concept modified with my experiences from using said adapter extensively over the last weeks.
First and foremost, the adapter sits closer to the camera body. This was necessary to get infinity focus for the Oude Delft Rayxar 50/0.75, because the travel required exceeded what was possible in the threads of the mounting adapter. The adapter bayonet mount now is seated approx. 2mm deeper.
Another important lesson from the Mk.1 was the need for a more sturdy Z-mount. The lenses used are very heavy and are turned many many times by the fine threads on the adapter, thus excessive wear quickly developed on the cheap ultra-thin M42-Z adapters I normally use.
I solved all issues referred to above by using a 77-58 step ring as a mounting platform, This will accept a genuine factory Z mount, of which I still have a few left. The Z bayonet was force-fitted inside the 58mm threads by judicious use of a wood block and a hammer :). A few minutes worth of Dremelling on the outside of the step ring removed enough material to allow the 77-58 + Z mount to be -- again -- force-fitted into the big threaded mount for the lens. No glue or screws were used this time.
The final touch is making a small notch on the side so as to allow my finger tip to press the lens release button of the camera.
The Mk.2 "production time" was less than 1 hour as completing the adapter didn't involve pondering what bits and pieces to use.
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The adapter seen from the inside. The rim along the Z bayonet serves as a stop to prevent the mounted lens from going too deep inside the camera throat.
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Here is the Rodenstock 50/0.75 on the Z30. I just barely managed to keep the capture from being completely blown by overexposure :) A lens "speed" of f/0.75 in daytime puts demands on the resulting shutter speed.
Towards infinity focus the image circle with acceptable quality becomes smaller and this needs to be taken into consideration for objects at the periphery.
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Main point here is you succeeded to utilize the Nikon Z mount cameras for these old Speedy lenses, Very well done!
I too hope we find time to meet up, maybe in Norway or Netherlands if there is anything I can help with I will gladly see what I can do!
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A key to understanding these lenses, and how to use them for actual shooting, is to learn the actual image circle projected and its behaviour when focus varies. The image circle at infinity focus is approx. 23mm for the Rodenstock TV-Heligon 50/0.75, and at least 26mm for the Oude Delft Rayxar 50/0.75. The circle is smallest at infinity focus and will enlarge as the lens is focused closer. Concomitantly, field curvature, spherical aberration, and coma increases and eventually will be manifested also in the near centre of the frame.
In the typical X-ray application, two superfast lenses with apertures in the f/0.7-f/1.1 range were used either facing front to front or back to back. The usual close-focus loss of lens 'speed' was avoided by the design, thus very weak X-ray images could be viewed on a TV monitor and/or recorded onto film. as shown below
(http://forum.mflenses.com/userpix/201411/big_455_xraydevicesketch_1.jpg)
From forum.mflenses.com
The TV-Heligon obviously was intended to transport the image onto TV. The initial record was through a corresponding XR-Heligon lens. The rôle of the Rayxar apparently is similar to that of the XR-Heligon, if I understood the [Italian] description at http://www.marcocavina.com/articoli_fotografici/Rodenstock_De_Oude_f_0,75/00_pag.htm . For our photographic applications, either system could be put to good use.
Another Norwegian, Espen Susort, describes his modification of the Rodenstock for Sony A7 cameras here: https://espensusort.no/2021/03/rodenstock-50mm-f-0-75-4/. I just became aware of his posts when my own adapters had reached the first prototype stage. Evidently, the additional 2mm of register distance of the Sony cameras created additional issues in the quest for infinity focus. His comments and the published test image for infinity focus clearly indicates he couldn't quite reach true infinity focus with his setup. He claimed best performance from 1.5 to 10m which is not consistent with my own observations. The lens indeed is at its sharpest for infinity focus, as it should be, and the performance graciously declines when the lens is focused closer. This behaviour is shared between the Rodenstock TV-Heligon and Oude Delft Rayxar lenses, and reflects the design criteria for their intended application as a component of a tandem relay system for X-ray machines.
Thus, the quality section of the projected image circle might be quite small, but with judicious framing of the subjects, we can make interesting images with most or all of what the lens projects. The aberrations increase very rapidly outside the core area, as evidenced below where I show the peripheral part of a Z9 frame done with the TV-Heligon. This was a blue-hour capture done well after the sun had set and thus the street lamps provided intense point-light sources.
Also note that even with the lens focused to a subject approx. 500m away, the depth of field still is inadequate to include much of the middle ground subjects. Consider the vintage of the lens and the effective speed of f/0.75, the lens really is amazingly sharp in the central parts of the frame. The designers needed 9 high-refractive elements in 6 groups to achieve such a performance, which obviously came at a considerable expense in its time.
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Amazing way to visually explain image characteristics from the center to the edges. Outside the explanation, it gives me an impression of acceleration, of momentum and some deliberate haste.
Thanks for sharing it!
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Here is the Rodenstock 50/0.75 on the Z30.
Love this image.
Thanks for the explanations, Birna.
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One is *not* forced to shoot these 'X-ray' lenses at near infinity of course. Having a focusable adapter means it is far easier than before to get the precise framing one requires, whether at distance or in close-ups.
Protea by Rodenstock TV-Heligon 50/0.75 on the Z30. I slightly widened the internal port over the sensor to avoid the rear parts of the lens conflicting with the frame there. The lens now focuses perfectly to infinity also on this DX camera. Trimming was quickly done using a small scalpel :)
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At intermediate distances, the Heligon covers the DX format adequately, but the longer away the focused plane is, the smaller the image circle is. Still, if the Z30 is set to 1:1 format (16x16mm), one can fire away without too much concern about of black corners. Some smearing might occur, but it is easily absorbed in most scenes and of course, if the entire DX frame is in use, judicious cropping is always feasible to maximise the useful part of the frame. Sharpness in the centre part of the frame is amazingly good.
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Here is another example, with the Z30 again. Focus a little closer this time. The outcome is surprisingly sharp across the frame and the bokeh is smooth and silky.
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The "image signature" of the lens is slightly to the "blue side"?
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That would likely depend on the colour balance set?
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Ok....yes....the white-balance? ....if it is set to auto or pre-set or set in post processing?
The light up there in the north may have more blue color now than during summer time?
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My Nikons are usually set to Auto w/b. That tends to bring colour rendition into the ballpark as it were.
The 'X-Ray' class of lenses are not designed for white light thus there is no guarantee their output is neutral. However, I haven't seen major colour casts from the optics itself. The Rodenstock and the Oude Ddelft lenses render colours slightly different as well.
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It is a quite interesting look. "Film" like color. A bit "pastel look"?
I tried the Kodak Ektar 100 yera ago. Think it reminds me a bit of Ektar 100 color look.
My Z50 is also set to Auto.
I wonder if the manuel pre-set D1, D2 etc is where you shoot a calibration target. I have not yet spent any time on the white balance options.
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A key to understanding these lenses, and how to use them for actual shooting, is to learn the actual image circle projected and its behaviour when focus varies. The image circle at infinity focus is approx. 23mm for the Rodenstock TV-Heligon 50/0.75, and at least 26mm for the Oude Delft Rayxar 50/0.75. The circle is smallest at infinity focus and will enlarge as the lens is focused closer. Concomitantly, field curvature, spherical aberration, and coma increases and eventually will be manifested also in the near centre of the frame.
In the typical X-ray application, two superfast lenses with apertures in the f/0.7-f/1.1 range were used either facing front to front or back to back. The usual close-focus loss of lens 'speed' was avoided by the design, thus very weak X-ray images could be viewed on a TV monitor and/or recorded onto film. as shown below
(http://forum.mflenses.com/userpix/201411/big_455_xraydevicesketch_1.jpg)
From forum.mflenses.com
The TV-Heligon obviously was intended to transport the image onto TV. The initial record was through a corresponding XR-Heligon lens. The rôle of the Rayxar apparently is similar to that of the XR-Heligon, if I understood the [Italian] description at http://www.marcocavina.com/articoli_fotografici/Rodenstock_De_Oude_f_0,75/00_pag.htm . For our photographic applications, either system could be put to good use.
Another Norwegian, Espen Susort, describes his modification of the Rodenstock for Sony A7 cameras here: https://espensusort.no/2021/03/rodenstock-50mm-f-0-75-4/. I just became aware of his posts when my own adapters had reached the first prototype stage. Evidently, the additional 2mm of register distance of the Sony cameras created additional issues in the quest for infinity focus. His comments and the published test image for infinity focus clearly indicates he couldn't quite reach true infinity focus with his setup. He claimed best performance from 1.5 to 10m which is not consistent with my own observations. The lens indeed is at its sharpest for infinity focus, as it should be, and the performance graciously declines when the lens is focused closer. This behaviour is shared between the Rodenstock TV-Heligon and Oude Delft Rayxar lenses, and reflects the design criteria for their intended application as a component of a tandem relay system for X-ray machines.
Thus, the quality section of the projected image circle might be quite small, but with judicious framing of the subjects, we can make interesting images with most or all of what the lens projects. The aberrations increase very rapidly outside the core area, as evidenced below where I show the peripheral part of a Z9 frame done with the TV-Heligon. This was a blue-hour capture done well after the sun had set and thus the street lamps provided intense point-light sources.
Also note that even with the lens focused to a subject approx. 500m away, the depth of field still is inadequate to include much of the middle ground subjects. Consider the vintage of the lens and the effective speed of f/0.75, the lens really is amazingly sharp in the central parts of the frame. The designers needed 9 high-refractive elements in 6 groups to achieve such a performance, which obviously came at a considerable expense in its time.
The point light sources here are captivating! Like a bird to an angel to a fish!
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The most mundane objects take on a nice glow through the 'eye' of the superfast lens, in this case, De Oude Delft 50mm f/0.75 Rayxar on the Z9.
(https://nikongear.net/revival/index.php?action=dlattach;topic=10638.0;attach=57060;image)
Pink iron is of course a favourite in my new existence :)
In principle, I could have obtained the similar image with this lens on the Z30, because the latter camera in its present state allows focusing the Rayxar to approx. 2m distance before there is a conflict between the rear end of that lens with the film gate. More work with a scalpel or Stanley knife is required :) For the Rodenstock TV-Heligon, having a smaller rear end, there is no conflict and this lens will go all the way to infinity even on Z30.
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Another close-up with the Oude Delft lens. Again on the Nikon Z9 and I was able to utilise most of the FX frame for this capture..
(https://nikongear.net/revival/index.php?action=dlattach;topic=10638.0;attach=57119;image)
The sharpness of this lens even for closer scenes is surprisingly good. However, compared to modern optics, the image contrast is fairly low and remediating steps might be required in the post-processing stage, at least for some subjects I'd presume.
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Very nice soft smear and Bokeh transition
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Love how it creates the background out of "nothing". Everithyng Get new meaning and body through the lens
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Very early morning blues at the first crack of dawn. A challenge for the Rodenstock TV-Heligon 50mm f/0.75, here on the tiny Z30.
(https://nikongear.net/revival/index.php?action=dlattach;topic=10638.0;attach=57156;image)
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Action shooting with these 'X-ray' lenses is both funny and frustrating at the same time. One really has to do an approximate initial focusing to be able to catch any moving subjects, due to the fine-pitched threads of the focusing adapter. It is doable, though, here with the Rodenstock 50/0.75 grafted onto the tiny Nikon Z30. I cropped the frame to include the centre which shows less issues with smearing. Still a good number of pixels left.
(https://nikongear.net/revival/index.php?action=dlattach;topic=10638.0;attach=57190;image)
As the shutter speed of the Z30 maxes out at 1/4000 sec and the lowest ISO is 100, I now add an ND 8X to the lens for daytime shooting with the Z30. This is not mandatory for the Z9 if I set the camera to ISO equivalent 32 as the top 1/32000 sec. speed usually suffices.
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The Rodenstock 50mm f/0.75 is excellent for shooting buildings !! This is one of the tallest buildings in Oslo and only the bridge in the foreground discloses the peculiar character of the image circle of this superfast lens. An ND8X filter was added to the Rodenstock as the tiny Z30 only has a top speed of 1/4000sec which is insufficient to deal with the light transmitting ability of the f/0.75 lens. As here, almost at infinity focus, the true nominal f/0.75 aperture is manifested and most if not all colour aberrations vanish as well.
The vantage point was too low to get the entire building rendered and I couldn't move back further lest I should fall into the Oslo Fjord :)
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Shooting the Rodenstock 50mm f/0.75 on the Nikon Z30 is advantageous firstly because most if not all of its DX format can be used for the final photograph, and secondly because pixel density is slightly higher than on the Z9. On the flip side, one cannot get the 'crystal ball' look with the DX camera since the projected image will be cut off.
With the Z30, an ND filter usually is required for daytime shooting lest massive overexposure should occur. The top 1/4000sec. shutter speed is *slow* when it comes to this kind of ultrafast lens :)
This early morning I required ND8X on the Rodenstock to bring exposures on the Z30 into range.
(https://nikongear.net/revival/index.php?action=dlattach;topic=10638.0;attach=57201;image)
Although inherent image contrast is low and even lower during a thick snow fall, there is plenty of image detail to pull out in post-processing.
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For portraits, the 'X-ray' lens comes into the middle-to-near range in which spherical aberrations creep in and softens the image. Still, the 'X-ray' effect can be pushed further to enhance the final outcome.
(https://nikongear.net/revival/index.php?action=dlattach;topic=10638.0;attach=57218;image)
A portrait of one of my transgender friends. She enjoyed the portrait :)
Achieved with Rodenstock TV-Heligon 50mm f/0.75 on my Nikon Z30.
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I am curious about the expected results of combining two RAF camera adapters with the 0.75 42mm TV Heligon, on a Z6.
This 70>42 was designed for the lens, and is a prefect fit. The bottom of the lens sticks about around 2mm.
https://rafcamera.com/adapter-m70x1f-to-m42x1m
The Z>42 of course has a warning not to directly attach lenses ;-)
https://rafcamera.com/adapter-m42x1f-to-nikon-z
If used in conjunction with their Z>42 adapter would it bring the lens close enough to the sensor to help it focus further out? Never expecting infinity focus, but I would like to find a way to use the lens for other than extreme close-ups. (I currently use the lens with the 70>42 adapter and a BORG Z mount.)
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No harm in trying? Just remember to set your Z6 to 'silent mode' to avoid any clash between rear part of the lens and the shutter curtains.
The projected image circle of the 42mm lens probably is a bit smaller than with the 50mm designs.
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I’ll report back once the adapter has arrived.
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Since the threaded adapter for the 42mm lens is 70mm, which is wider than the camera mount, you can test the possibility of getting infinity focus already with the items you have. Just set the camera to 'silent mode', push the lens flush to the mount, and look what is shown on the screen.
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One is *not* forced to shoot these 'X-ray' lenses at near infinity of course. Having a focusable adapter means it is far easier than before to get the precise framing one requires, whether at distance or in close-ups.
Protea by Rodenstock TV-Heligon 50/0.75 on the Z30. I slightly widened the internal port over the sensor to avoid the rear parts of the lens conflicting with the frame there. The lens now focuses perfectly to infinity also on this DX camera. Trimming was quickly done using a small scalpel :)
Absolutely gorgeous
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Finally got all the parts: 52m to 65m ring; 65m to 65m 17/35mm helicoid; 65m to z mount.
If using only the 52 to 65m and the 65 to z mount, the lens is flushed with the camera. Still, infinity is not reached, more or less 200 meters
First image, lens as close as possible to the sensor, focused on the antennas-ish
Second, a little screw work got me to focus on the hanging clothes.
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With adapter ring + helicoid + mount, the maximum focus distance drops to a little over 1 meter. A couple of shots to show magnification. and a extra one just because I had it on my hands :)
All images with a Z6 body
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Well, not exactly what we had hoped for. However, you now can focus the lens .... and the helicoid could be replaced with something slimmer, perhaps? There are 10-11mm extension tubes available.
Paco, if you can provide detailed close-ups of the rear end of the lens mount, I can evaluate whether a bespoke solution using a factory Z mount and a 58-65mm step ring is feasible. That might shave off 1-2mm.
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There you go.
1.: 52m to 65m; 65m to 65m 17/35mm helicoid; 65m to Z mount.
2.: step up ring installed
3 and 4.: step up ring + mount adapter. This is as close as I can get to the sensor. I think the rear actually touches the plastic just before the sensor. It focuses at maximum of 200mts, more or less
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Same thing but using the helicoid.
1 and 2: the lens is of course farther away, bigger magnification and less vingeting. With this set up it focuses from approximately 1 mt down to a few ctms, as shown in the pictures above.
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Nicely done ;)
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Getting so close to the sensor makes me worry about IBIS. Am I wrong to worry?
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No danger, as the cutout frame in front of the sensor will limit how close to the sensor surface the 95/1.4 lens can be seated. However, my Oude Delft Rayxar 50/0.75 goes much closer, to approx. 1mm, for infinity focus. I try to ignore this and shoot away, then if required clean the sensor on a later occasion :) (this is with the Z9, but will also work on the Z6/7 if these cameras are set to silent mode).
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To get a larger area covered by the "X-ray" lenses, image stitching is a possibility. For this I tend to use the tiny Nikon Z30 to host the beefy Rodenstock 50mm f/0.75 TV-Heligon. with this camera, my Oude Delft 50mm f/0.75 Rayxar won't focus properly to infinity (it goes to around 100m, which is far off infinity foucs) due to the slightly larger rear element which interferes with the innards of the camera.
Provided enough image overlap is present, image quality can be impressive. 100% crop of a large panorama is shown here. Right click to open image in a separate window to view it in full size.
(https://nikongear.net/revival/index.php?action=dlattach;topic=10877.0;attach=60756;image)
It was snowing, in case viewers wonder about the white specks all around :) Not image noise.