NikonGear'23
Gear Talk => What the Nerds Do => Topic started by: BEZ on April 08, 2016, 23:10:57
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In 2013 I asked Bjørn Rørslett how to mount my newly acquired DE OUDE DELFT RAYXAR E65/0.75. He suggested we start a thread on the old Nikongear site.
Here are the photographs that were posted when I asked the question.
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Here are Bjørn's instructions......
Posted 06 December 2013 - 20:12
As usual you can attack the modification of such lenses in different ways. There is no golden rule.
However, whatever you do remember this lens is very heavy. So any attachments must be able to hold the load.
A simple yet efficient approach is as follows;
Remove the retaining shroud at the end of the lens. Be care full so the rear lens cell doesn't drop out.
The removal discloses a thread which is small and pretty delicate. It can be used if you find the appropriate counter-threaded items. I do have used this approach once or twice but now find it's too weak to be trusted for a lens used in the field.
Instead, use either 40.5>52 or 42>52 mm step rings. Remove the smaller thread (Dremel at the rescue) so the adapter is flush on one side. I think 40.5 will have a light opening large enough, 42mm will give less support but should still suffice.
Put the modified adapter onto the rear of the lens ensuring it is flush to the cut-out of the main lens casing. The 52 mm threads should point backwards.
Add the retaining shroud and screw it home so the adapter is securely held in place.
This procedure will give a clean 52 mm female interface. A BR-2/2A will give a Nikon F mount but beware the reflex mirror of the camera. You can add a spacer such as a K-4 to avoid any issue with Nikons. Alternatively, find a suitable transition from 52 mm to m43.
Posted 07 December 2013 - 11:27
Another tip if you go the 52 mm way ending with the first adapter showing 52 mm female threads. For F mount use a BR-2 or similar plus a spacer (K-4 or similar). For m43 mount, add a step-down 52>42 mm which will present a flat outer surface to which you can attach say a C-mount>m43 adapter (the one by Fotga is perfect as it is thin yet very robust) by running three screws to hold these together. If you wish to use the Rayxar on a CX-mount camera (1 Nikon series), make a similar setup but substitute C-mount to CX instead.
You now have a versatile system in which you can easily juggle between 3 different camera mounts. Many of the "fat" X-ray lenses (Rodenstock Heligon, Oude Delft Rayxar, Kowa, Canon) can be dealt with in a similar fashion. The basic point is using the 52 mm thread as the common interface for all versions. The 52 mm threaded item has the strength to hold these heavy lenses securely, something which is less obvious with the smaller diameter threads.
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Here is my lens with the mount fitted.......
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Here is the beast fitted to a baby M43 camera....
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Here is the very first photograph I took with the lens mounted on a D800....
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The little sister of the big Rayxar 65 mm f/0.75 is the Oude Delft 50 mm f/0.75. Still labelled 'Rayxar', but in another league regarding heft and bulk.
The 65 mm f/0.75 with one out of several adapter solutions I have made for it. This version sets the rear lens cell as deep as possible into the F-mount yet still clear the mirror. (I did manage to get the cell pushed further backwards later, alas no photo of that, and the mount is now rearranged for Sony E).
(http://www.suracephoto.com/wp-content/uploads/2016/04/bjorn1.jpg)
These various approaches to get a mount for the 65 mm illustrate there are no definite rules or solutions to adhere to. Except you always have to consider the stability of the connection with such a heavy lens.
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A few Rayxar 65 snapshots.
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Were these Rayxar lenses originally intended for X-Ray use like the Heligon's?
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Yes they were fitted to Phillips X-Ray machines
Cheers
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It is common to see the glass inside such lenses, be they Heligons or Rayxars, take on a brownish tinge. No doubt a result of high-refractive rare earth glass and massive X-ray impact.
I have seen a diagram of the optical setup used in these X-ray devices. Probably in one of my optical textbooks. Must locate and copy so we better can understand why these lenses were designed as they are.
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BEZ: That is a cool project. Looking forward to meeting you again in Scotland!
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Hello Frank,
I am looking forward to see you also ....I have a nice bottle of Saint-Émilion with your name on it, ready to bring to Killin ...see you soon!
Cheers
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Here is my lens with the mount fitted.......
So the the package contains a BR-2 on the camera side and a 40.5-52 step up ring on the lens side. What is the thing in the middle?
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My quick and dirty solution:
1) Nikon F to 52mm adapter from ebay
2) 52-55 step down ring
3) 55-52 step up ring
4) 52-40.5 step up ring
2-3 are simply for spacing. With this, the rear element is about 1.5mm from the rear of the F-mount bayonet (recessed, not sticking out).
There are two things I'm worried about:
1) Suspending the lens from the mount for prolonged time. I would prefer to have a tripod mount on the lens itself.
2) The 52-40.5 ring has considerable play (as Bez showed with his caliper, the outer diameter of the lens case is considerably smaller than the inner diameter of the 40.5 side of the ring. Thus, the ring is only secured by the rear screw of the Rayxar lens (the part shown in Bez' 2nd picture) by friction.
Any suggestions?
Here is the rig on the FT-1 and Nikon 1 V1:
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A spacer. Apparently BEZ just knocked out the glass from a 52 mm filter.
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A tip: the lens will be much more flexible and thereby useful if you drop the FT-1/F-mount part and attach it directly to the 1 Nikon.
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A spacer. Apparently BEZ just knocked out the glass from a 52 mm filter.
Ok, seems that his package leads to the same spacing as mine, or very close. The rear element seems to have almost the same position.
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A tip: the lens will be much more flexible and thereby useful if you drop the FT-1/F-mount part and attach it directly to the 1 Nikon.
Yes, that would be more flexible. Unfortunately, the Nikon 1 to 42mm adapter that I have is not accepted by the V1, the camera complains that no lens is attached. One should have an adapter with dummy contacts I guess. I wonder why the contact-less adapters are even being sold since they don't work.
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You need to set the camera to M mode and your problem is solved ....
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You need to set the camera to M mode and your problem is solved ....
Thanks! :D I always have it on M normally, and it didn't even cross my mind that it could have been accidentally set to A. Now I simply need to find a 52-42 converter..
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Ok, seems that his package leads to the same spacing as mine, or very close. The rear element seems to have almost the same position.
Yes as Bjørn guessed it was a skylight filter to keep the rear element clear of a DSLR mirror ....But I mostly use the lens on my fuji mirrorless cameras as they have a shorter register distance. Your package does not take advantage of this on your V1.
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Yes as Bjørn guessed it was a skylight filter to keep the rear element clear of a DLSR mirror ....But I mostly use the lens on my fuji mirrorless cameras as they have a shorter register distance. Your package does not take advantage of this on your V1.
Thanks! Yes, but I guess it all depends at which magnification you want to deploy the lens. With this package, the working distance is a guessed 20cm. Some shots on FX:
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Thanks! Yes, but I guess it all depends at which magnification you want to deploy the lens. With this package, the working distance is a guessed 20cm. Some shots on FX:
But you may as well have the benefit of your FX sensor if you don't want more working distance with your V1.
Why have you left the heavy original mounting ring on?
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But you may as well have the benefit of your FX sensor if you don't want more working distance with your V1.
Why have you left the heavy original mounting ring on?
Yes, I guess it's too early but the combination of different rings will make it possible to change the camera very quickly on the fly. If the lens can be securely mounted on a tripod, changing the camera on the back side will be very easy.
I haven't yet thought about what to do with the mounting ring. Currently, I leave it on because the threads underneath are quite greasy, so it's more comfortable to hold the lens like that. I want to see whether I can find someone who can machine a large aluminium ring for me with an Arca Swiss dovetail. The ring could either be designed to attach to the mounting ring or to the large male threads.
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I want to see whether I can find someone who can machine a large aluminium ring for me with an Arca Swiss dovetail. The ring could either be designed to attach to the mounting ring or to the large male threads.
I considered something similar but decided I will never use the lens on a tripod so dismissed the idea.
Just remember to always hold the lens to avoid straining your camera mount.
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2) The 52-40.5 ring has considerable play (as Bez showed with his caliper, the outer diameter of the lens case is considerably smaller than the inner diameter of the 40.5 side of the ring. Thus, the ring is only secured by the rear screw of the Rayxar lens (the part shown in Bez' 2nd picture) by friction.
Any suggestions?
I don't have the lens at hand to check but I used a 39mm or smaller to 52mm ring that was more secure than a 40.5mm, It bolts down very firmly.
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I don't have the lens at hand to check but I used a 39mm or smaller to 52mm ring that was more secure than a 40.5mm, It bolts down very firmly.
Thanks, that makes sense!
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Thanks, that makes sense!
A quick look on ebay and 37mm to 52mm are common ....be careful not to remove too much of the 37mm threaded ring else you will not get a tight fit ....too little and your rear element will be lose in the retaining shroud.
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Gotta love the "Made in Holland" markings, that alone should make one land in my camera bag :)
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Do consider the weight first ....
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Very nicely adapted all of them! And super images ;)
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Do consider the weight first ....
Yes, it weighs roughly 1.5 kg.
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A few diagrams to help people understand why these specialist lenses exist in the first place, and why they are so heavy and rugged.
Basically they help transport the X-ray image into safe viewing positions. The final image can be recorded to [cine] film or TV media.
(http://forum.mflenses.com/userpix/201411/big_455_xraydevicesketch_1.jpg)
The first lens is the collimating lens and the second is the recording lens. Due to the construction and placement, there is no conjugate loss of light.
For X-ray screening, limiting the exposure to unhealthy radiation is a primary concern. Hence the use of ultrafast lenses in the imaging system.
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Interesting!
Do you have information about the refractive indices of the different elements inside the lens?
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Must be very high, if you look at the strong curvature and thickness of the elements Usual speed is f/0.75 or thereabouts.
These X-ray lenses were very expensive, but nothing compared of course to the total price of the X-ray device they were a part of !!
(http://forum.mflenses.com/userpix/201111/big_455_Screen_00211_1.jpg)
Copied from a post Klaus Schmidt made at forum.mflenses.com, original seen in Sidney E. Ray (2002): Applied photographic Optics. Focal Press, as noted by him.
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A simple diagram of the elements with measurements ....internet folklore says if you remove the rear element you achieve focus at infinity.
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Interesting. The drawing indicates the rear lens cell actually comprises 2 groups. Although there is an air space indicated, this seems to be absent when you extract the entire rear cell as it comes off in one piece not two?
If the entire rear cell is removed, focus on a mirrorless camera can go to several meters, but quality is really bad.
It should be possible to make a dedicated digital setup for this lens for infinity photography by literally standing the lens directly onto a sensor. The cover glass of the sensor will act as the final air spacing.
I do notice the two lens diagrams are not identical. Are there several versions of this lens as well? (BEZ removed one of the diagrams because it might refer to another lens)
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Bez, where did you find the lower picture with the rays? Given enough sample rays, one could infer the refractive indices of all the elements.
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It should be possible to make a dedicated digital setup for this lens for infinity photography by literally standing the lens directly onto a sensor. The cover glass of the sensor will act as the final air spacing.
A digital version of this ....https://sites.google.com/site/francoisastrocat/
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Bez, where did you find the lower picture with the rays? Given enough sample rays, one could infer the refractive indices of all the elements.
Good luck with reading the text :) .....http://plaza.rakuten.co.jp/utsurundesu/diary/200810040000/
Google gave the image as Rayxar 65mm f0.75 ....but on investigation (This guy's blog) I don't think it was correct. Interesting how close the Heligon is in design.
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A digital version of this ....https://sites.google.com/site/francoisastrocat/
Exactly what I had in mind.
The image circle is probably quite small, thus a m43 sensor should suffice.
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I do notice the two lens diagrams are not identical. Are there several versions of this lens as well?
I think my Japanese let me down (and Google) ....the second diagram may of been a Heligon, so I have removed it to save confusion.
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Exactly what I had in mind.
The image circle is probably quite small, thus a m43 sensor should suffice.
It would seem relatively simple to achieve with a donor m43 camera?
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The problem is that the hosting camera has to be complete butchered and the shutter probably must go. Thus a model with electronic front shutter could be advantageous. The bits & pieces must be put into a light-tight box - probably easy . and the controls be available on the outside.
Apparently infinity focus is obtained with 4-5 mm of clearance to the rear element. Still I don't think there is room for a shutter curtain, but this can be investigated further.
A good project for a Nerd subgroup of NG?
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I forgot about the shutter ....it now seems trickier
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I removed the entire rear lens cell and now it will be possible to get infinity on a Panasonic or similar camera. However, as I said, image quality suffers.
However, being experimentally inclined, I think we should dare to split the 2-group rear cell as there cannot be much refractive power in the very last element, plus there should be an airspace to effectuate the split line. The two groups are joined by a metal film (to my eye), thus judicious use of a thin chisel or similar should do the trick in prying the groups apart along the air space.
If this strategy works, there should be little problems getting the "Infinity Rayxar" functional on a bespoke m43 camera with a nice high-resolution sensor and good ISO performance.
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You confirmed the make up of the rear cell then ...I remember mine slipping out when assembling the mount and I thought it was a single element.
I read a blog where the author rearranged the elements of the lens to achieve various focus distances, including infinity. His example images were not convincing so I did not save the link.
I will try and find it, in case it contains any points of interest.
Personally I would not want (brave enough) to separate the rear element as I enjoy the lens in standard form. I realise your curiosity (bravery) is much stronger than mine.
What would be your main interest in using the lens at infinity?
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"Because I can" -- natural curiosity. A new twist on familiar scenes. Etc.
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You might be able to do with a camera without a mechanical shutter. A few m43 models offer a completely electronic shutter, but you will be limited by the rolling shutter effect. Maybe a Nikon 1 model also has a fully electronic shutter. However, I have no idea, if said cameras will even boot up without their mechanical shutter unit.
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By removing (partially or entirely) the rear lens cell, the working distance gets much longer and there will in principle be no problem with a shutter curtain. Except for the [focusing] mount, which has to be a bespoke design, various cameras could be attached and probably these won't need much of a modification, if at all.
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I've been doing my own experimenting with X-Ray lenses and infinity focus and while I can not speak to the De Oude Delft Rayxar, the Heligon 100mm f/1.5 and the Kowa 42mm f/0.75 can achieve infinity focus by the removal of certain elements and other means.
I don't want to derail this thread though with those experiments, perhaps a new topic.
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I've been doing my own experimenting with X-Ray lenses and infinity focus and while I can not speak to the De Oude Delft Rayxar, the Heligon 100mm f/1.5 and the Kowa 42mm f/0.75 can achieve infinity focus by the removal of certain elements and other means.
I don't want to derail this thread though with those experiments, perhaps a new topic.
Charlie,
I think it works continuing the conversation here ...but here or on a new thread, I am interested in your experiments
Cheers
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Hi! Very interesting thread :). I'm in the process of adapting my E65 and can't figure out wether I should split the rear element or not as Bjørn was saying.
I'm more interested in using this lens for landscape or night skies than macro/proxy photography so getting rid of the rear element is going to happen but I don't really understand what the last thin layer of glass is supposed to do.
Bjørn, did you do it at the end? If you did, what do you think now?
Plus, has anyone tried to adapt this lens on medium format?
Cheers!
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In order to achieve infinity focus with the 65/0.75, the distance rear element to image plane has to be less than 4 mm. Even on a mirrorless camera this is not possible if there is a shutter curtain present.
Adapting this lens to medium format has only meaning if one shoots close-ups, as the image circle is pretty small and doesn't even cover 24x36 for anything else than close focusing. Be aware the curvature of field is extreme.
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Ok. So I'll have to redefine my goals a little then, forget about infinity/far focussing. What is the further you could achieve focus?
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If lens is mounted in a light-tight box, without shutter, you can get infinity focus. There are descriptions of such 'deep sky' cameras on the 'net.
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Couldn't one make a relay that takes and puts it further away to not interfere with the mirror? This would be more cost effective than building a custom camera.
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So Bjørn, if I follow correctly. If I mount the lens on a box with bellows or something, and create a ground glass for it. I could then achieve infinity focus, and I would "simply" have to take a picture of the ground glass, or scan it. Right? (of course scanning for a dark sky isn't practical but for daylight landscape I think it would work, don't you?)
Cheers!
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In principle, yes, but all advantages of using a superfast lens is lost. In order to show an image, the screen has to break up the aerial image thus it must have grain and this structure - literally - is engrained in your final image. Plus the projected image would be bright on the optical axis and probably dim elsewhere.
Simone's idea of an optical relay circumvents some of these issues, but the overall "speed" drops dramatically.
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Well, it's not really the speed that I'm looking for with this lens. It's more the extremely shallow depth of field. If it was for the speed, I'm OK with the couple 0.95 lenses I already use. But anyway, I hear you.
If I could find a way to get around these problems, that would be even more interesting.
Is there somewhere an accurate measurement of the "film" coverage one can get from this lens? When I removed the rear element, I got something larger than fullframe but I can tell for sure how large I can get with it.
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At far distance, focal length has a huge impact on depth of focus / depth of field so for instance a 400mm f/2.8 has very little dof if you focus on the night skies,,, even at f/2.8