focotar 40/2.8 on Leitz focomat Ic

[nokton]

Hello friends,
I just register this forum 2 mins ago... look like people in this forum are specialist.

I just bought a Ic + focotor 40/2.8 (i understand that this lense was originally for v35, but it should also fit Ic, right?)

However, having mounted it on Ic... I found that focuing is impossible (not sharp). No matter how I turn the focusing mount (from very left to very right), the image is still not sharp.

Any adjustment in anywhere I should do first?

Thank you in advance.

 

[palec]

Focotar 40/2.8 fits the screw mount of Focomat I (standard 39mm thread), but I'm not sure if it's also usable on it. Focomat I is built for 50mm enlarging lenses. If you want to use shorter focal length lens, the lens should be placed closer to film (focus) plane. If you want to use longer focal length, the lens should be placed farther from it.

Neither Focomat has belows system which can universally adapt different focal length lenses just the helical mount fixed to specific focal length. This is bigger problem with replacing le8ses in Focomat IIc (you just can't replace 60mm lens with 50mm on it).

On Focomat I there should be an adapter ring (15 or 16mm width ) between mount and lens. I think it's obligatory for use of 50mm lens. You may try to remove it to get closer to focal plane. If it's not there, the lens might be too close. Try to unscrew it and move it in your hand up and down until you'll see sharp image. I guess you'll need 8mm width ring to fit 40mm lens. I'm just guessing here, but I alternate 40mm and 50mm on V35. 40mm does not need adapter and 50mm needs 8mm adapter. Simple math suggests it should work out.

Anyway, WA-Focotar 40/2.8 is generally not recommended for condenser system, as it has some fallout at the edges, V35 is said to be compensating it with it's double lens diffuser.

 

[palec]

Btw. Welcome on RFF board!

 

[Tom A]

What Palec says rings true. The Focomat 1c with the 50 focotar f4.5 usually requires a spacer ring (15mm) between the lens and the enlargers mount. The 40f2.8 has most likely a shorter back focus and needs to be closer to the mount to work properly. I dont have a 40f2.8, but I do have a 50f4.5 Focotar-3 ( it is a prototype lens for the V 35) and that one works on my late 1c.
Unscrew the lens and see if the spacer ring is attached to the enlarger ( stick your finger into the lens cavity and if it is there, it will feel like a collar) Unscrew it and try the lens again. Be careful when you turn the helicoil for the focussing, it can be completely unscrewed and it is a nightmare to reinstall.
I have tried the 40f2.8 on one of my Focomat's long time ago. Not that impressed with its performance. I prefer the Focotar 50mm f4.5 - and that one can be made to couple with the autofocus system of the 1c.
50mm enlarging lenses are plentiful and cheap. The Focotars tend to be at the top, but lenses like Nikkor 50f2.8 and f4 and the 63mm nikkor f4 are much better than the 40f2.8 on the Ic's. The 50mm can be used in autofocus mode (you have to calibrate the enlarger for it though) - the 63mm is too long to use in autofocus - but works fine in manual focus.

 

[Ronald M]

I have put mine on the Focomat IC using a shorter extension tube. Being a wide angle lens, the lens will vignette badly and the edges are very soft. DO NOT waste you time.

The same lens works perfectly on my V35. The mixing box is made with thicker material in the center so as to even the light on the V35.

A 45 mm APO Schneider works poorly on all my condenser machines projecting soft corners, but it works perfectly on my diffusion machines. It is not an allignment problem.

Final answer is avoid wide angle lenses on condenser enlargers.

 

[nokton]

Thank you very much guys!
Very impressive for your replies!

 

[nokton]

Hello,
So now I will try to get another lense. so this time 50mm, no mistake.

Any good 50mm lense recommended?
My friend recommend APO-Rodagon 50/2.8: this one good?
Shall I assume that all 3-party lense can do the auto-focus function, as long as it can be mounted on ths Ic and get focus sharp the 1st time?