Enlarger sharpness at the stop

MiTo · 2021-03-08T07:53:48+00:00

Hallo zusammen, mein Name ist Michael, bin neu hier im Forum und in meiner Dunkelkammer. Wie es dazu kam, das zu beschreiben dauert hier zu lange - es hat...

MiTo

Hello everyone, My name is Michael; I’m new to this forum and to my darkroom. It would take too long to explain how I got here – it’s certainly got something to do with lockdown, which is why my cameras from 20 years ago have found their way back to me. Right from the start: I’m a complete novice when it comes to anything to do with darkrooms. I’ve read quite a bit and have a lovely old book here, but that’s about it. I started with a small Durst enlarger – now there’s a (also small) Meopta Opemus 6 with Color 3 sitting next to it. My problem is focusing on the enlarger. With both machines, I have to turn the lens all the way up to the stop. With the smaller paper sizes, I might have a tiny bit of play to turn it downwards. Is that normal? (Although that makes me wonder why the enlarger has such a long focus travel) As I’ve been developing the negatives myself from the start, I thought I might be doing something wrong. So I got hold of some old negatives developed by the lab. But it’s no different there. Am I missing something, or is it actually like this: Enlarging (to larger formats) involves: turning the lens (50mm) all the way towards the negative (KB), then raising the head until the image loses its sharpness. That is then the largest scale. For me, that’s about 16x12 cm; any larger and the sharpness is no longer present. In the hope that I’m missing something and larger enlargements are possible, best regards to everyone Michael

AnalogfotoRostock

Hello Michael, You need to adjust the size of the print by raising the head and then focus using the small wheel on the lens. To focus, pull the negative frame out one notch; a focus line will then appear on the enlarger screen (one line when in focus, two offset lines when out of focus). When focusing, the image may become smaller again; if so, you’ll need to turn the head up a little further. The bellows are extended for high enlargements and sit closer to the lens for low enlargements. Best regards, Malte

Renate

Hello Michael, From your description, I get the impression that there is something wrong with the lens or that the mechanism on the enlarger is jammed. The Opemus 6 can be focused on a 30x40 cm print on the base bed. However, you need to be careful when screwing in the 50 mm lens. The Opemus 6’s lens plate has a curve that allows the distance between the lens and the negative to be preset. With the 50 mm lens, the ‘hump’ must face the negative so that the distance to the negative is reduced. With an 80 mm lens (for medium format), the ‘hump’ must face the paper. Best regards, Renate

MiTo

Renate wrote : "Hello Michael, The lens plate on the Opemus 6 has a curve that allows the distance between the lens and the negative to be preset. With the 50 mm lens, the ‘hump’ must face the negative so that the distance to the negative is reduced. With an 80 mm lens (for medium format), the ‘hump’ must face the paper. Best regards, Renate

Hello Renate, I couldn’t resist and during my lunch break I turned the valley into a hill. Problem solved :D Thank you very much! The world looks completely different now.... Michael [hr]

Analogfoto Rostock wrote Hello Michael, you need to adjust the size of the print by raising the head and then focus using the small wheel on the lens. To focus, pull the negative frame out one notch; a focusing line will then appear on the enlarger screen (one line when in focus, two offset lines when out of focus). When focusing, the image may become smaller again, in which case you’ll need to turn the head up a little further. The bellows are extended for large enlargements and sit closer to the lens for small enlargements. Best regards, Malte

Hello Malte, thank you very much for your reply. Is the bit about ‘pulling the negative frame out one notch’ the same for all models? I hadn’t even noticed there were notches there before. I’ll have a look into it, though Regards, Michael

AnalogfotoRostock

Hi Michael, that’s certainly the case with my camera, an Opemus 5: you can pull out the negative holder in two stages; the first stage is used to move the negatives and, of course, to focus. Best regards, Malte

MiTo

Analogfoto Rostock wrote : "Hi Michael, that’s certainly how it works on my camera, an Opemus 5: you can pull the negative holder out in two stages; the first stage is for moving the negatives and, as you say, for focusing. Best regards, Malte

I’m actually quite excited right now; I’ve felt the notches and seen the two lines. Do you also know what those two knobs/levers on the negative frame are for, to the right and left of the glass? And while I’m at it: those sliding things you use to mask the negative are quite wobbly and also a bit crooked. Is it worth opening the whole thing up and… I don’t know, cleaning it or tightening it up a bit? Regards, Michael

MiTo

Hahahaha... never mind, I can adjust the negative size using those two little levers. After Maltes mentioned those brilliant focus lines, I suppose I was expecting yet another marvel of engineering. :D

AnalogfotoRostock

Just use the little levers... The negative screens aren’t actually meant to define the frame—you do that using the enlargement frame on the plate—but simply to block out stray light roughly. That’s why it doesn’t matter too much if they’re crooked. I’m sure you could unscrew the negative frame and have a look at them, but is it really worth it?!