Enlarger lens adaptors?

[cerber0s]

I just purchased two enlarger lenses on an online auction, no information except a bad photo. One is a Nikkor 50mmm f4, the other turned out to be a Meopta Belar 75mm f4.5.

It turns out (I didn’t know), that my enlarger has a 42mm lens mount, but the Nikkor has, I assume, 39mm. The Meopta has 23.5mm.

I figure I can get a m42 to m39 lens adaptor for the Nikkor. That should work, right?

Is there an adaptor for the Meopta? Is it even worth the effort?

I paid $15 for the both of them, and they both turned out to be clear and free of fungus and other issues.

 

[xkaes]

You have two options -- find adapters (step-up/down rings) or find/make new lensboards.

Either will work fine.

What is your enlarger?

 

[cerber0s]

You have two options -- find adapters (step-up/down rings) or find/make new lensboards.

Either will work fine.

What is your enlarger?

Thanks!

It’s a Polish Krokus. It’s OK, but the lens is pretty crappy.

 

[xkaes]

Thanks. It's possible that Krokus made other boards most likely 39mm, but finding them? That might be hard. I suspect that your best approach is to find metal or hardwood or plastic (of the same thickness) and cut it to the same size. Then cut a hole in the center for the size of the lenses (1-2mm larger than the rear threads) and simply attach them with rear lock nuts / jam rings.

 

[Petrochemist]

Thanks. It's possible that Krokus made other boards most likely 39mm, but finding them? That might be hard. I suspect that your best approach is to find metal or hardwood or plastic (of the same thickness) and cut it to the same size. Then cut a hole in the center for the size of the lenses (1-2mm larger than the rear threads) and simply attach them with rear lock nuts / jam rings.

With a small lens, you can probably even make do with elastic bands instead of the lock nuts (which means you don't have to find the right thread. making the hole as close as possible to the rear threads is preferable with this approach.

I have some Wray enlarger lenses that are smaller than m39. Possibly the same size as your Meopta. They came with an adapter to M39

 

[xkaes]

I've seen 25-39mm etc. adapters on EBAY regularly. I've even sold a few there.

 

[MattKing]

In case it isn't obvious, if your enlarger has a 25mm hole where the lens is supposed to go, it is harder to adapt that for a 39mm threaded lens than if your enlarger has a 39mm hole and your lens has a 25mm thread.
I don't know if the Krokus uses replaceable lens boards, or has a fixed threaded mount that cannot be changed.

 

[cerber0s]

In case it isn't obvious, if your enlarger has a 25mm hole where the lens is supposed to go, it is harder to adapt that for a 39mm threaded lens than if your enlarger has a 39mm hole and your lens has a 25mm thread.
I don't know if the Krokus uses replaceable lens boards, or has a fixed threaded mount that cannot be changed.

It has a plate with a 69 or 70mm hole that has a screw in adaptor for 42mm. The plate with the 70mm hole is attached with 4 screws, the adaptor from 70 to 42mm can easily be removed by hand. I’d assume that there are replacement adaptors for the Krokus to go from 70mm to whatever. I’ll look around. Or just buy a 42 to 39mm adaptor ring, those are around $9.

Is the Meopta lens any good? Would it be worth the effort to find an adaptor for it? Or will I want to stick with the Nikkor?

 

[Mal Paso]

50mm lens for full frame 35mm. 75mm for 2 1/4 square (6x6cm).

 

[MTGseattle]

Please someone correct me if this is wrong, but can't the Nikon be used in the 42mm board with a retaining ring?

 

[MattKing]

Please someone correct me if this is wrong, but can't the Nikon be used in the 42mm board with a retaining ring?

If the threads are long, and you have two oversized retaining rings, perhaps - as long as you added something else to ensure centering.
The 3mm difference is actually quite large.

 

[cerber0s]

Please someone correct me if this is wrong, but can't the Nikon be used in the 42mm board with a retaining ring?

I was thinking something like this

M39-m42 linsadapter m39 lins till m42 kroppsring...

M39-m42 linsadapter m39 lins till m42 kroppsringadapter för ringkropp

swe.grandado.com

 

[Petrochemist]

I was thinking something like this

M39-m42 linsadapter m39 lins till m42 kroppsring...

M39-m42 linsadapter m39 lins till m42 kroppsringadapter för ringkropp

swe.grandado.com

I'd call that a stepping ring (it screws into both threads) a retaining ring just screws into the thread on the lens & clamps the lens against the board.
Yes a stepping ring like that should mount it nicely.

 

[ruilourosa]

Belar is not a very good lens, but anarets up to 20x30, are, and they come in 25mm also.

 

[MTGseattle]

Thank you Matt. I didn't even think of potential centering issues.