Problem with coverage on Beseler 45

[wkjagt]

Hi all!

I just bought a Beseler 45MCR enlarger with a Rodenstock Rogonar-S 150mm lens. My problem is: when projecting the negative, the projected image has black corners. This doesn't change when I try to print smaller, so I am guessing it is not the lens (150mm should be able to handle 4x5 anyway). The negative is as close to the condensor as possible. I think this configuration should give no problems... I looked in the condensor and the two lenses have the round sides facing eachother. That's probably the way it's supposed to be, right?

It looks like the black corners are the round corners of the condensor, because I can actually focus on them, making them sharp black edges.

Is there anyone who can help me out with this?

Thanks a lot in advance!

[nolindan]

Beseler 45MCR enlarger with a Rodenstock Rogonar-S 150mm lens. My problem is: when projecting the negative, the projected image has black corners.

It is possible to focus past the negative carrier and image the rounded corners of the condenser mounting collar 'through' the aperture of a 4x5 negative carrier. However, when focusing on the negative you should be within the condenser illumination.

You do have to have the film stage cranked all the way up. Lowering the film stage by 1/8" can bring the edge of the condenser mount into negative carrier aperture.

[wkjagt]

You do have to have the film stage cranked all the way up. Lowering the film stage by 1/8" can bring the edge of the condenser mount into negative carrier aperture.

I have it cranked all the way up until it won't go any further... It it ok that I can still see a part of the upper bellows? It's only in the back that the neg carrier holder and the condensor holder (sorry for the awful terminology) are touching...

[wkjagt]

Ok, I am one step closer to a solution.

I took the lenses out of the condensor and I think it wasn't assembled correctly. From top to bottom it had:

- top condensor lens
- large aluminium cylinder to keep the top lens from sliding down
- bottom condensor lens
- round piece of thick green glass
- large metal ring

So the bottom two pieces created a distance between the bottom lens and the film. I put the bottom lens in first, then the cylinder, then the top lens, but I have the piece of green glass and the ring left. Does anyone know the right order of all the parts in the condensor? It does cover 4x5 now (only just, no space for printing a black border though...) but I would like to put all the parts back ;-)

And does anyone know what the little door is for on the front side of the condensor? It gives acces to the space between the two condensor lenses. Is it for some kind of really big filter?

Sorry for all these questions, I only have printing experience, no repairing experience ;-)

[Bob Salomon]

And does anyone know what the little door is for on the front side of the condensor? It gives acces to the space between the two condensor lenses. Is it for some kind of really big filter?

;-)

That is the filter drawer.

Did you say that the negative stage was touching in the back and not the front? If so then you are very out of alignment.

[Bill Kumpf]

My 45M required some shimming at the lower stage to correct the alignment. It also will shift the negative stage down during focusing if the it is not locked in place.

Check out the Beseler site for the assembly drawing.

http://www.beselerphoto.com/img/exploded.45mxt.body.gif

[Jim Noel]

Ok, I am one step closer to a solution.

I took the lenses out of the condensor and I think it wasn't assembled correctly. From top to bottom it had:

- top condensor lens
- large aluminium cylinder to keep the top lens from sliding down
- bottom condensor lens
- round piece of thick green glass
- large metal ring

So the bottom two pieces created a distance between the bottom lens and the film. I put the bottom lens in first, then the cylinder, then the top lens, but I have the piece of green glass and the ring left. Does anyone know the right order of all the parts in the condensor? It does cover 4x5 now (only just, no space for printing a black border though...) but I would like to put all the parts back ;-)

And does anyone know what the little door is for on the front side of the condensor? It gives acces to the space between the two condensor lenses. Is it for some kind of really big filter?

Sorry for all these questions, I only have printing experience, no repairing experience ;-)

All of these parts are necessary. The green glass is heat absorbing glass and should be on top facing the light source, so it just sounds like the condensers were in upside down.

[wkjagt]

Thanks a lot for that drawing! It helped me put everything in the right order. Everything was indeed upside down.

Last question for now:

I think the negative carrier should still go a bit closer to the condensor. The top part of the carrier has round edges on top that fit perfectly in the bottom part of the condensor. This is probably so that the carrier stays perfectly centered when the condensor is in the 4x5 position (but i might be wrong). But the carrier doesn't get close enough for the edges of the carrier to enter the condensor hole. I think the condensor should still go a bit closer to the film. This would also be nice if I want to print full frame (black edges) The bottom of the condensor is big enough: when I put the film on one of the condensor lenses, it doesn't touch the edges of the condensor.

(Does this make sense? If not, I'll try to take a photo of it.)

[mikebarger]

anyone know how to realign the carriage? Our movers somehow got the carriage out of aligmentment, maybe a tooth on one side???

Thanks

Mike

[Bill Kumpf]

This is hard to read but maybe it will help.

http://www.tech-diy.com/45mxt.htm