240mm 5.6 Rodagon up on Beseler

[Neal Chaves]

I have a Beseler 45VXL with the Beseler 8X10 cold light conversion. It came with a 240mm f9 Beseler HD lens for 8X10 enlarging. It has been a fine lens for me despite a number of bad reviews. Many writers have said that the 240mm 5.6 Rodagon will not mount up, but after taking some measurements I felt it would. When one came on the market at a favorable price last week, I bought it. It took me about an hour to mount it to a standard 4X4 Beseler lens board with a drill press and simple hand tools. After I cut the hole for the flange with a fly cutter, I had to trim the flange on two sides and relocate one mounting hole so that the lensboard will fit into the mount.

The major reason why a lens with a large, protruding rear element like the 240mm 5.6 Rodagon will not mount directly to a 4X5 Beseler is resriction of the throat because of the need to mount a lens turret. The turret turns in a circular opening, and part of this arc cuts accross the top left corner of the 4X4 lensboard opening. I notched out the arc with a sabre saw because I don't use a turret. Even if I did mount a turret, I doubt that the notch would affect its operation. I cut this notch some time ago so I could mount my 250mm f6.7 Fujinon which has been a good enlarging lens for me.

In the photos you can see the enlarger throat with the notch cut. then the lens mounting plate in place showing the full square area now available, the 240 Rodagon mounted on a 4X4 Beseler lensboard with modified flange, and finally the lens mounted on the enlarger. It sure is bright wide open at 5.6 compared to the F9! I think I'm going to like this.

[ic-racer]

How did you center the lens on the light source and then center the negative to the lens? I use a versalab laser and center it on the concentric diffraction rings from the lens, draw an x on the baseboard at that point and go from there.

[Neal Chaves]

How did you center the lens on the light source and then center the negative to the lens? I use a versalab laser and center it on the concentric diffraction rings from the lens, draw an x on the baseboard at that point and go from there.

Everything is factory stock except for that notch I cut out. I centered the lens on a stock Beseler 4X4 lensboard which mounts in the standard position. If it is centered close enough for Beseler, it is close enough for me.

[ic-racer]

Everything is factory stock except for that notch I cut out. I centered the lens on a stock Beseler 4X4 lensboard which mounts in the standard position. If it is centered close enough for Beseler, it is close enough for me.

Ok I see, thanks for sharing. Nice modification.