So you think your lens is fast?


by Bellamy /

2 min read

So you think your lens is fast?
During the course of my job I have seen and heard of more ‘superfast’ lenses than you can shake a stick at. And after a while it just becomes a parade of the same old thing. But then something comes along that completely blows it all away. Meet the De Oude Delft 50mm 0.75! Faster than greased lightning.

We have seen them all, the ‘superfast’ lenses. I am talking about the 0.95’s of this world. The ones that make folks weak at the knees with bokehlust™. And then we have all heard of the Zeiss 0.7 50mm, the one that Kubrick was so fond of that of the 10 lenses made, he bought 3 of them.
But the Leica and Canon fast lenses of this world are pretty easily accessible if you have the cash. And no amount of money in the world is going to get you near one of the Kubrick lenses (unless you are prepared to sell your organs). So how to you get that extra speed? Well, you get one of these…


This is the remarkable De Oude Delft Rayxar E50mm 0.75 lens. Yes, read it and weep. That is 0.75! If that doesn’t get your Bokehlust™ flowing then I don’t know what will.


This hefty (and frankly impractical) lens was made for Xray systems and is actually not all that hard to find if you are prepared to look. But this one has been engineered by Miyazaki R&D to fit an M mount. So now you can have this incredibly fast lens on your M-mount camera. If you are prepared to, as this is a bit of an unusual lens. You see, because it was made for Xray, it doesn’t have an aperture or a focusing system. The lens is permanently set at 0.75 and permanently set with a focus area of about 2 metres. I say about, as it is different for each camera that it is mounted on and the depth of field is so impossibly shallow that you really need to have live view working to get things right. Added to the fact that it almost obscures the finder, this is a challenging lens. It looks cool though.


As this lens was not designed with a 35mm camera in mind the image circle doesn’t actually cover the whole frame, instead giving you ‘halo’ effect images. You can see some images taken with the lens here (link). It certainly has some interesting effects.

I was commissioned to have this lens made by a customer and it certainly threw up some challenges. But it was a great deal of fun and it has produced an interesting lens. If you have one and want to get it converted then get in touch. Sorry, this particular lens is not for sale.


11 comments on “So you think your lens is fast?”

    ZDP-189 March 7, 2014 at 3:17 pm / Reply

    These aren’t expensive lenses and would make a fun project. I am sad that a man of his talents couldn’t add focusing, RF-coupling and an iris, though.

    Anders W March 7, 2014 at 10:20 pm / Reply

    I bought a Rodenstock TV Heliar lens 0,75/50mm. I converted it with a M42 thread adapter, which I glued in place. Then I bought a EOS – M42 adapter with a diaphragm. Very nice for macro work and surprisingly good contrast when smaller apertures are used. The lens is HEAVY!!

    Stephen March 8, 2014 at 1:27 am / Reply

    From looking at those sample shots this seems like a sweet still life lens but so difficult for portraiture! Nifty find, though.

    Dan March 8, 2014 at 12:07 pm / Reply

    I have nothing to add except that I appreciate your mention of the Kubrick Zeiss lenses. Barry Lyndon is a beautiful film.

    Dave Powell March 20, 2014 at 2:55 pm / Reply

    I think they did something very right with the design here. I have always wondered why my Noctilux had an aperture ring…

    Andreas Kaufmann May 9, 2014 at 6:34 pm / Reply

    Well, a lens where you can’t focus (which means no helical mount – this lens is just a huge piece of glass in my opinion!) is in my understanding a fixed focus lens – Elcan did a 1/90 for M-Mount in the 70ies, but at least they added focus rings which you could screw in at the back. And no iris, hmmm, so there are no mechanical parts involved…

    Jukka Vatanen November 1, 2014 at 5:00 pm / Reply

    To me the portrait images look like the ones I got with a magnifying glass glued into a metal tube and a nikon slide copying bellows. I think I should have engraved “Jukka 75mm f: 0,9” to it and sell for a couple thousand US Dollars…

    Alexis January 19, 2015 at 5:05 am / Reply

    I’m just curious — why is there a trademark designation on “Bokehlust”?

      Bellamy January 19, 2015 at 9:02 pm /

      For jokes.

    D Mac March 6, 2015 at 12:12 pm / Reply

    I’ve actually found quite a few makers of f/0.75 X-Ray lenses; Rodenstock XR-Heligon 50mm f/0.75, Precise Optics 50mm f/0.75, Varo Optical 50mm f/0.75, Leitz 65mm f./0.75

    There are also a number of longer f/0.95 – f/1 lenses in the 90mm range from the same lens manufacturers. I’d like to see some 90mm f/1 portraits.

    Hogarth January 22, 2016 at 10:04 am / Reply

    when I saw this kickstarter, I knew I’d seen this lens on your site. It is silly to me, they are using kickstarter to sell m mount lenses.

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