help Industar-50 3,5 / 50

Generally speaking, there are two types of legacy lenses... ones that fit old rangefinder cameras, or the ones that fit old SLR cameras. The distance between the lens mount to the back of the camera body is shorter in rangefinder cameras because there is no mirror.

Usually lenses with M39 threaded mounts are rangefinder lenses, and M42 threaded mounts are SLR lenses - BUT, not always.

It seems that the adapter you need for your Industar-50 is the longer M42 adapter (but you need a step-up threaded sleeve that will change your lens from M39 to M42 threads.



Another way (smaller and better looking IMHO) of doing it is to add a "spacer tube" in between your M39 adapter and your Industar-50.

You can buy an "M39 extension tube" sets, they are not expensive. They usually come in several tube lengths (all M39 thread) which can be joined all together or separated individually. Make sure the set you buy has one that is 16mm long, I think this is what you need so that your Industar-50 will be able to focus to infinity (this is what worked on my M39 Mir-1). The link below shows a set with extension ring lengths of 26mm, 16mm, 8mm, 5mm.

4 EXTENSION TUBES tube Step-up rings ring for M39 Leica FED mount camera 930 | eBay

The downside is that your pancake lens, won't be so compact anymore. The bonus is that you can add the other unused tubes later to take macro shots with any of your M39 lenses.

 

From what I could find (M39 lens mount - Wikipedia, the free encyclopedia)...

If this is correct, you'd need a 16.4mm extension tube to make it focus correctly. Since the lens probably doesn't move far in the focus movement, the lens as-is is focusing beyond infinity, which is why is always looks blurry, even when set to the minimum focus distance.

 

Here you go buddy.

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Pic shows two identical Russian lenses. The one on the left is an early edition MIR-1 (M39 screw at the back), and on the right is a later model MIR-1W (M42 screw at the back). If you look closely at the adapters, the short L39-NEX adapter (left) PLUS a 16mm extension tube becomes similar in length as the long M42-NEX adapter (right).

To check infinity focus, you can view focus peaking of a random object at the horizon with multiplication factor x9.5
If infinity focus is not perfect (some lenses vary like my vintage Paxette lenses) you can add thin washers which you can cut from black cardboard or plastic sheets. You add the washers in between the lens and the adaptor. In my case, the MIR-1 works perfectly with just the 16mm extension tube without any additional washers.

Although the product description of the Russian M39 Extension Tube Set says that the tubes are 26mm, 16mm, 8mm, 5mm in length - the 16mm tube is actually 16.4mm (16.3mm in my case). The Russians knew what their local lenses needed for interchangeability. So make sure you get a Russian made Extension Tube Set, like the one in the link.

 

Indeed you are the fountain of all knowledge dioptrick.!

 

I'm a little late to this party, but you have just answered a question that came up yesterday, regarding my Paxette lens.

Thank you