Focusing issue with 80mm enlarger lens

[eob]

Hi there,

I recently purchased a Schneider 80mm enlarger lens so I could print 120 film. I have an old Krokus 66 enlarger and lots of 120 film to be printed. However, I can't seem to focus no matter what I do. The negative will focus with a 50mm on the enlarger, but not with an 80mm.
What am I doing wrong? I've extended the Krokus to as tall as it can go, but nothing, just blur.

It says on the front that f=80 lens is 0.9 ÷ 8. If that means anything to anyone.

Any help would be appreciated.

 

[Martin Rickards]

I don't know the Krokus enlarger, but on my Meopta the lens board is domed. For 35mm the lens is recessed and closer to the negative and for 120 negs the board is reversed making the distance to the negative greater.

 

[eob]

Thanks for the reply. Unfortunately my Krokus doesn't have that feature. At it's highest, the lens is 70cm/27.5 inches away from the board. Would you know if that's adequate for an 80mm lens?

 

[Martin Rickards]

The critical measurement here is likely to be the negative carrier/lens distance and I would have thought that Krokus had either a separate carrier for the 50/80 mm lenses or used a similar system to that of the Opemus I described. Looking up some details, it seems that the Krokus takes M42 lens mounts,not the normal M39 as well.

 

[choiliefan]

Have you tried removing the lens and holding it in the enlargers light path to see if an image can be formed farther away than the bellows allows? Should help determine if you need a deeper lens board.

 

[cowanw]

It is not the distance to the board but between the negative and the lens. This link suggests that there are indeed different lens boards.

https://www.photrio.com/forum/threads/krokus-enlarger-lens-question.16013/

Another link suggests there are different condenser sets. There is a colour head to use without condensors on ebay now
Lastly is there a bellows and if so max out its length and try.
Or something like this might be what you need or to get your mind thinking of a make do.
Search ebay for "Ring for photographic enlarger KROKUS and thread 70 mm/42mm"​