De Oude Delft Rayxar 50mm f0.75

Lens Data

Lens Unit

Lens Photo


Purpose   for X ray
Photograph distance  2m fix
Weight   N.A. 
Filter  77mm fixed with tape


Lens Impression
レンズ構成図を見てもわかるようにレンズ後部はかなり細くなっており、もしかしたらライカマウントの内側にうまく入るかという期待を持たせてくれます。しかしそのままではとてもCCD面直前にレンズ後部を持ってくるほどの出っ張りではありません。さらに後部ふくらみ部分には、M8用のマウントを追加しなければいけませんので、とても不可能と諦めておりました。しかしなんとか最低限の撮影は不可能なものかと、「困った時の宮崎頼み」ということで、いつもの通り、MS Optical R&Dの宮崎さんに相談すると、「確約はできないけれど、できるだけのことはしてみる」ということでした。

The back focus of an original lens has only about ‘1-2mm’. And it has neither diaphragm nor Helicoid on this lens. As seeing the lens construction, the rear part of this lens becomes considerably thin and gives me some feeling that it seems possible to go into the Leica mount. However, it is not enough length that brings the tail of lens rear at just before the CCD. Furthermore, since the mount for M8 had to be added to the rear portion of the lens, I was almost giving that it was very impossible.
However, concerning whether it is not possible to take the minimum photography, I remembered "Ask Miyazaki when troubled". I consulted Mr. Miyazaki of the MS Optical R&D, and he replied ‘it is impossible to promise to accomplish, however do the best’.
And it is this lens to have been completed.
Dent cut to the bone itself until just before touching the glasses of the posterior body of the lens, and superbly equipped with M mount. I prepared to become it exclusively for close-up photography if the distance from the lens rear to CCD should be longer, but had remodeled to improve that the focus came to with approximately 2m by technology of Mr. Miyazaki (fixed focus).


I took photos of late spring flowers around home to let the big lens expose to outer air.
Because the shape of a picture of this lens with only 1mm back focus taken by Leica M9 becomes round, I trimmed to be a square photo.. The description at center is rather sharp although this lens has no apperture blade and can be taken at full apperture. Strong radial bokeh comes up around peripheral area because of aberrations (astigmatism or curvature).
Soho area

I tried more difficult snap photos. People are moving towards me and they should realize if I hold the camera looking though the finder in such short fixed focus at 2m. So all photos are by No-Finder shot. Although it started becoming dark in the evening, I could shoot almost at 1/250 second thanks for the extremely fast aperture at f0.75 and make the people still in photos.
British Museum

When I take a snap photo of a person with this lens, because the focus distance is fixed 2m, I think there are two methods mainly. One is that to push the shutter button to the person coming to the distance of this lens and the other one is to take the photo of the person who is keeping still at the distance of 2m. The museum is suitable in such a meaning. Moreover, the British Museum is best because it is free.
Hydepark Christmas Market

I challenged snap photos of children with this severe conditioned lens of "No diaphragm, only at 0.75 and 2m distance is fixed, and the exposure meter does not operate". The measurement of the distance is all manual. As the result,,, a wonderful description has come out. Although many of them came by luck, of course, it was worth performed the lens reconstruction forcibly if this lens amuse me with such soft and warm pictures.


I took the trial photos. At first the lens tail is just before CCD, it cannot cover the whole screen of M8. The second piece of the examples is an original full screen image. Other examples cut the surrounding by about 20 percent. As expected, it has considerably soft description, and a considerable blur seems to come out on a focus part. Although I can not see such strong taste like swirling bokeh, there seems considerably having an astigmatism, and a coma aberration in the peripheral area. The radial astigmatism seems to strongly appear in the most edge part, but which usually cut away.

Photos with Delft Rayxar 50mm f0.75