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05-09-2019, 04:40 PM   #1
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Using K-Mount Lenses With Helios M42 Bellows

I am looking at getting some macro bellows, specifically the Helios variant. However the majority that are available are the M42 threaded variant; though there are some which are k-mount.
The camera which I use is a Sony a6000 with a focal reducer for the collection of k-mount lenses I have.
I would like to use the bellows with my k-mount focal reducer and lenses, though I am not entirely sure what I am looking for to replace the M42 mounts or to adapt.
The bellows mounts themselves appear to be interchangeable.
I have included some images of the k-mount variant below.

Any help would be greatly appreciated!

05-09-2019, 05:09 PM - 1 Like   #2
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Your best option to adapt a K-mount lens to an M42 bellows is to reverse the lens onto an M42 reversing ring. Since you are working adapted on the camera end, that is less of a problem.

05-09-2019, 08:45 PM   #3

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Don't know this bellows unit at all, but it looks like those set screws should back out and the lens mount would pop off.
Get any old K-mount extension tube to replace the screw mount on the front end and you should be in business.

Steve's idea is a good one too, at these distances will not matter which direction you look through the lens

You do know this would be without any automation, you need lenses with an aperture ring, (K, or M, or A) and you would focus wide open, then manually stop down to expose,
Slow and prone to error (from brutal experience with film, many years ago)
05-09-2019, 09:20 PM   #4
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Why not buy the K-mount bellows version? There is one listed on eBay UK at the moment:

Helios Macro Bellows For Pentax PK Mount | eBay

It even has the box!

Edit: There is a company here in the US that will make custom adapters to order. They will make an adapter with female K-mount bayonet and male M42 threads. As I recall the minimum extension it will add is 15mm. The price as I recall is in the $120-150 USD range. At that price you may as well find a nice Pentax Auto Bellow K, M or A with slide copier attachment. If you are interested I can post or PM you the link to their website.

Last edited by Not a Number; 05-10-2019 at 08:25 AM.

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