Set max enlargement on Durst M800 with 50mm lens

klausentreiben · 2018-01-04T15:43:26+00:00

Liebe Forenfreunde, nach dem mein alter Durst M 800 dreißig Jahre im Keller verweilte, habe ich ihn nun endlich aktiviert und mein Wissen aus alten Laborklub...

klausentreiben

Dear forum friends, after my old Durst M 800 had been sitting in the cellar for thirty years, I have finally got it up and running and put my knowledge from my days in the darkroom club to good use. As the enlargements of 35mm film using a 100mm/4 Meopta lens turned out too small in the first test – presumably this focal length is required for enlargements of 6x6 or 6x7 negatives – I bought a Schneider Componon S 2.8/50mm lens. ? Now to my question: I was only able to illuminate a maximum of 23cm x 34cm of a 35mm negative with it; by then the lens stage was fully retracted and I could just about make out the grain in the focusing screen. However, there was still 38cm of free space at the top of the stand, meaning the enlarger would allow for even higher enlargements if the focus weren’t at its limit. ? a) Have I reached the maximum enlargement? Would it only work if I used a wide-angle lens, e.g. a 40mm? Actually, I thought that the enlarger could achieve higher enlargements thanks to its tall column and swivel head. ? b) The enlarger has a swivel head. This is usually used when the standard column is too short. But even in this case, the enlargement would be limited by the focus extension. So what’s the point of all this? ? c) How does the whole thing behave if I try to achieve an enlargement of a 35mm negative or a 6x7 negative using the 100mm lens?

Wolf_XL

...I reckon you need to turn the lens mount round and screw the lens on from the other side – then there should be enough play to focus...

Wolfgg

... or, instead of the standard lens mount, use the one where the lens is recessed (= sits closer to the film). You can usually tell this is the case because you can no longer see the lens aperture. Best regards, Wolfgang

klausentreiben

Thanks for the tips. So, without a reverse ring or other accessories, I’m stuck. Which option will offer the better quality? A recessed lens or a reversed one? Will I definitely achieve a higher enlargement with a reversed lens? I suspect that I’ll then be pushing the focus extension tube or the column to their limits as well, as the proportions are different. Has anyone had any specific experience with this?

Magirus

Hello You need to use a lens that’s been submerged (please not in a pond). This brings the lens back within the normal focusing range. Best regards, Bernd

Urnes

To use the 50mm lens, it must first be positioned 50mm away from the negative. For the 100mm lens, the distance is 100mm. You focus by increasing the distance to the negative using the bellows. It looks as though the 100mm lens is positioned correctly for you. Consequently, the 50mm lens needs to be moved closer to the negative. Depending on the design, if the lens plate – the metal plate into which the lens is screwed – is curved, you can simply turn it over and then screw the 50mm lens back in. It should then be in the correct position. However, if the plate is flat, you’ll need one that’s curved inwards like a cup. You can also use the 100mm lens. That’s no problem. You’ll just have to try it out to see how much magnification you can achieve with it. With the 50mm, the image will definitely be larger on 35mm film. Regards, Sven

Wolfgg

It says here in section 5.0.0 – you don’t need to know French to understand it – that it’s probably the LAPLA 39: € http://babardestcyr.free.fr/m800.pdf € Best regards, Wolfgang

klausentreiben

To use the 50mm lens, it first needs to be positioned 50mm away from the negative. For the 100mm lens, it’s 100mm. You then focus by increasing the distance to the negative using the bellows. It looks like the 100mm is positioned correctly for you. Consequently, the 50mm needs to be moved further away... Regards, Sven

Thanks for that – I’ll measure the 50mm straight away. It all depends on the negative cassette used, of course. From your post, I gather that it should be at least 50mm and probably more when focusing. How does this all work in relation to the enlargement scale? I had the problems you mentioned when trying to go to maximum enlargement. Small-format prints, on the other hand, could be managed without any issues.

klausentreiben

It says so here in section 5.0.0 – you don’t need to know French to understand it – so it’s probably the LAPLA 39: € http://babardestcyr.free.fr/m800.pdf € Best regards, Wolfgang

Thanks. I really need to get hold of the instructions in German. As there’s only one board with an M39, I reckon I’ve got the right one.

Urnes

Unscrew the lens. Remove part no. 37 by loosening the knurled screws. Refit it with the curved side facing upwards. Screw the lens back in. It should then fit. Regards, Sven.

Renate

Part no. 37 is flat and can only be fitted in one direction. However, according to the instructions, it should work with the flat circuit board and a 50 mm lens at a minimum enlargement of 3x. This corresponds roughly to 35 mm film on 10x15 cm paper. It may be that the bellows has become a little too stiff, or that the lens has the wrong flange focal distance. Best regards, Renate

klausentreiben

Thanks, Urnes, I’ve now tested it properly. With the lens plate in its normal position, I get 31.8 cm × 21.2 cm from the 35 mm negative. So not quite the 24 × 30 cm image format. With the lens plate inverted (recessed), the dimensions are 34.5 cm × 51.5 cm.