Durst Laborator L900

[szklaneserce]

Hi,

I have a chance to cheaply buy a medium format enlarger, Durst Laborator L900. The problem is that the enlarger comes without lenses.
Therefore I wonder if:
1. Can I use any lenses provided the focal lengths match those of the original lenses (50 and 80mm)? Do the lenses need to be a matched pair (ex. two rodenstocks) or can they be from different makers (ex. one scheider and one rodenstock)?
2. The service manual says that the use of other lenses requires adjusting the autofocus mechanism. Points 2 and 3 of the instructions read: 2.Loosen the screws and remove the came plate 3. Put in the new pre-adjusted came plate and tighten the screws.

What exacly is this came place, what does it mean that it is pre-adjusted and does one need to buy a new one if one wants to use other than the original lenses?

3. Can the autofocus system be bypassed and the enlarger simply focused manually? Would that still require the adjustment of the 'came plates'?

Any help greatly appreciated
Cheers

 

[algis]

Last question first: you can focus the enlarger manually and bypass the autofocus feature.
Autofocus enlargers employed a system where the focus change of a (known) lens through the different enlarging heights was changed by a cam that was cut specifically for that lens. Once you installed a specified lens and its mating cam, you wold have to focus it critically for it to then work 'automatically' through its range. Wth some 'autofocus' enlargers other requirements were necessary, for example, the easel had to be of a specified thickness (in US manufactured autofocus enlargers the easel was specifies as having to be 1 inch in thickness for the system to work.

The Rodenstock lenses were probably the one Durst used when the enlarger was first made. A cam could be made for any lens, but that would run the costs up for what becomes , essentially, custom machining.

My suggestion is to fit any brand lenses you like and focus manually

 

[szklaneserce]

Thank you very much for the answer!
So a cam(e) is not the same thing as a lens board such as lapla, setopla etc.? I'm not familiar with technical english
Have you ever used this particular model of Durst? As far as I know Laborator L900 doesn't have a focusing knob like the one on M805...There is only this knob on the right hand side with an outer and inner ring, the inner being for rapid hight adjustment and outer for fine adjustment, but I wonder if it can be used for precise focusing?

 

[davidmasek]

You can use the helicoid on the lens mount for manual focusing. But it is not the best way to use this beast of an enlarger.

 

[szklaneserce]

What is a helicoid? As far as I know this Durst doesn't have bellows so I wonder how is manual focusing possible at all?

 

[szklaneserce]

Or do you just mean the thread on the lens mount?And adjusting the focus by screwing the lens in and out a notch?
That doesn'ts sound like the best way of focusing indeed
Thanks anyway

 

[Ron789]

I used one; it is indeed a beast! You can use it with any lens and simply focus manually by turning the lens mount. But then the size and weigt of this enlarger becomes a bit of an overkill and you might just as well use a simpler enlarger. I would recommend buying one or 2 Rodagons and enjoy the precision and ease of the L900 in autofocus mode.
Beware: you will need different condensors for different formats:
35mm: Bimacon 75 plus Femocon 50.
6x4.5, 6x6: Bimacon 75
> 6x6: Bimacon 80
Make sure the condensors you'll need are included; separate condensors are hard to find!
Also note that the maximum negative size is approx. 6x8.5; meaning that you cannot print a true 6x9 negative edge-to-edge.
Also make sure that you get the proper negative carriers for the formats you will use, and the glasses in the carriers are in good condition.
Good luck!