M-Minoxar, finally it's here!

douwe

douwe

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Hi All,

I just wanted to share my latest project, a conversion of a minoxar 35mm f/2.8 from a Minox GT-E to M-mount. Of course it's 'only' scale focus, but it works nicely on my A7, and reaches infinity focus without problems. I'm ready to shoot some film with it with my Konica!

It took a few prototypes, by I now have a working combination of a standard LTM-to-M adapter, a 3D printed middle part and the minox lens minus the shutter. The conversion is quite simple because the 3D printed part gives a good fit. Pictures to follow!

What do you guys think about it?

https://flic.kr/p/NVRd23

https://flic.kr/p/P3WiFG
 
U14380I1478886438.SEQ.0.jpg

U14380I1478886440.SEQ.1.jpg
 
Yes, I would also be interested in see how you removed the lens and if you are going to sell the adp.... I have a couple of Minox 35's that still work plus a ready Kiev 35 to take apart and use it's lens. The Kiev worked great for a short period of time and I thought the lens was not bad on it. Since it's just a copy of the Minox 35 it "should" come apart the same way or close to it any way.
 
Well, I can definitely document the conversion process. I want to make another conversion for a minotar and also one for the mc korsar of the kiev 35a.

The ltm-to-m adapter now already brings up the 35mm frameline in my hexar rf. The next step is to add a 'fixed fucus' cam to the 3d print that sets the viewfinder patch to focus at 2 meters. That would allow for the trap focus method.

I can also make the 3d print saleable at shapeways so that anyone interested can just order it too. 🙂
 
Oh, and the internals of the kiev lens are the same as the minox GT, apart from the dimensions of the lens elements. The lens is a sonnar design with 5 elements in 4 groups. Interestingly the mc korsar is front element focus just like the tessar-type minoxar. The sonnar lens of the rollei 35s was originally designed in the same fashion, but the design didn't perform well enough. It was redesigned as a unit focusing lens at great cost to Rollei. I'm curious how the mc korsar performs!
 
For all of you that want to take the lens out of a Minox, here's how to do it:
https://www.flickr.com/photos/96630454@N06/albums/72157660676074238

Please note that it is not a reversible project!

Some might wonder why I do not take out the plastic lens tube that has the aperture scale printed on it. The main reason is that the plastic tube would sit too far into the m-mount, it obstructs the rangefinder mechanism. A second reason is that bonding the adapter straight to the brass that holds the back element is a very sturdy solution.
 
thanks a lot for all this information + data. while i'm currently not up to do something similar, i'm quite curious about it - i might need to know some day ;-)
 
Thanks! I'm having a lot of fun with it. The lens really is high quality. I'm filling a roll of B&W with it at the moment... and thinking about further refinements!
 
douwe said:
And especially for JChrome, I made the 3D print available on Shapeways! 🙂

http://shpws.me/MUSv

625x465_16460446_9591927_1478992017.jpg


Once I make another myself I'll complete the tutorial to show the final assembly of the lens and the adapter!
Click to expand...



Mm... high definition acrylate. I've yet to see that (I've only ordered Strong and Flexible plastic from SLS printing).

If I didn't have some other important projects that burned up all of my time and resources, this one would be at the top of the list.


Sent from my iPhone using Tapatalk
 
douwe said:
Thanks! I'm having a lot of fun with it. The lens really is high quality. I'm filling a roll of B&W with it at the moment... and thinking about further refinements!
Click to expand...

Do you a photo of the back with LTM thread? how do you fix the lens on the adaptor?
 
Hi Guys!

I made some progress and improvements to the conversion method. Mainly, I added a fixed depth cam to the 3d print, that makes the rangefinder fix its focus at 3 meters. Now, when I set the lens at 3 meters as well I can 'trap focus' the lens, or move back and forth for perfect focus at 3m.

Also, I figured out that the 'black strong & flexible' material at shapeways is more dimensionally accurate than the more expensive high detail acrylate. So I made the print in that material instead.

Fixing the 3d print to the m39-to-m adapter ring was done with epoxy glue, I used the same to fix the lens to the adapter. It's super strong and the glue takes a while to set so it's easy to align the pieces properly.

Some photos will follow later on...
 
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