Andreas_23
Hello everyone!
Is there a reasonably decent way to enlarge Minox negatives using an Opemus 5? Second-hand Minox enlargers aren’t actually that expensive anymore, but I don’t want to have yet another piece of kit lying around that I only use once in a blue moon.
Many thanks and best regards,
Andreas
max
Hi Andreas,
I’m not familiar with the Opemus 5 – is that a 50mm or 50mm+6x6 enlarger from Meopta?
Anyway, I enlarge my Minox negatives using a Durst 138, which is designed for negatives up to 13x18.
How?
It’s quite simple: just use a standard 50mm lens.
You’ll need an insert for the negative holder; you can easily cut this out of black card (fold a 72mm-wide streak in half lengthways – it’ll then be as wide as a 36-exposure film – cut an 8x11 window through both emulations, and perhaps stick in two guide strips made of thin cardboard to ensure the Minox film is guided centrally)
The only problem is the magnification ratio, and of course my Durst is way ahead in that respect (long halls, 1m distance between lens and image is no problem, just an insane contortion if you’re lying with your eye on the focusing screen and trying to reach the focus knob with your hand). The Metr gives 1:20, so almost 16x22 (or 18x24 with borders). If your Meopta manages 50cm, that’s already 1:10, so 8x11cm (10x13 with borders).
So what’s the point of shorter lenses?
There are, for example, Componone lenses in 35 and 28mm (as well as various lenses from the era of half-frame, 16mm and other cameras)
Problem 1: Can your enlarger focus that close? You’d need to position the lens about 15 or 22 mm closer to the negative than with the 50 mm (at 1:10 and above, we’ll ignore the extension tube for now); let’s forget about the 16 mm, as that simply won’t work. The 35 mm might be focusable with a curved plate.
Problem 2: (only for condenser enlargers): can you readjust the light source accordingly? It needs to be closer to the condenser to ensure the illumination remains even.
Problem 2b: for diffusion enlargers, the light intensity naturally starts to diminish. This means long exposure times.
By the way, WA lenses won’t help you here; the working distance is largely normal, only the angle of view is wider. But that isn’t really the problem here.
On the other hand, the 35mm lens would at least achieve a ratio of about 1:14 at a column height of 50cm, so roughly 11x15.
Right, then the usual stuff: take the utmost care, stop down by 2 stops, don’t cough during exposure, focus as if it were your last, close the paper frame with velvet gloves, and readjust before every exposure. (Need I say anything more about dust?)
Good luck,
Martin
Andreas_23
Hello Martin,
Thank you very much for your detailed explanations. The Meopta Opemus 5 is essentially a 6×6 enlarger, which I also use for all my 35mm enlargements by using special format inserts and turning the lens plate upside down (so that the 50mm lens is closer to the negative). I can’t achieve a distance of one metre with it, but I didn’t want to enlarge the tiny negatives to larger than 13 x 18 cm anyway. At the moment, the unit is packed away dust-proof in a cupboard; otherwise, I would have measured it straight away. Let’s see how far I get with it. The tip about the negative holder made from construction paper is brilliant and so simple that I’m once again wondering why I didn’t think of something like that myself. I’ll try everything out and report back on the results.
Thanks again,
Andreas
cfb_de
Hi Andreas,
My Minox negatives also fit into the Opemus-5. For the image stage, I use AN glass at the top and a homemade cardboard mask at the bottom. I use the 35mm Anaret lens. You’ll need a recessed circuit board for this (the one from the 50mm isn’t big enough!) (I got the one for the even older Meoptas from Mirko back then and filed it down to fit).
Then 13x18 from Minox fits easily in the Opemus. When I get the chance, I’ll try out Minox negatives in the Ahel, as the column with the head raised is also 95 cm long.
Best regards,
Franz
max
Hi Andreas,
Before I forget, you’ll obviously need a bright lamp, as you’re usually working with large formats.
Of course, not much light gets through the small negative.
Alternatively, just use a loooong exposure. Still, it’s better to stay within two stops.
Best regards
Martin
grunke
Hi Andreas, please have a look inside your Minox.
You’ll notice that the camera has a curved image stage.
You should try to get a Minox stage from 321.. or thereabouts,
if you don’t want to end up with slight distortions.
Regards, Jäg ;)
max
Hi Jörg,
I’m not sure if that bit about the curved image plane also applies to the newer Minotars and the fixed-focus models...
Anyway, if it’s not architecture (or, of course, Russian submarine bases), but rather what you generally do with a Minox (street photography, people, snapshots, you know), it’s not really an issue up to 18x24 (or at least it doesn’t stand out in an unpleasant way). I’ve got a B model, which has the curved image stage; the enlarger has a flat one.
Gur?
Martin
MarcusD
:ph34r:
Hello MINOX fans!
The issue of the curved pressure plate keeps causing confusion and leading to incorrect statements about the suitability of MINOX enlargers or the enlargability of negatives!
In short: it DOESN’T MATTER what you combine with what. Every device – whether it has a curved pressure plate/mask or not – is, so to speak, a self-contained system.
Up until the first series of the C and the penultimate series of the B, MINOX cameras were built with the COMPLAN, a lens designed by Arthur Seibert (1906–1980), who also worked for Leitz. It was called Complan because the aforementioned curvature was factored in, which was intended to compensate for design-related edge blurring. For the photographic result, this means that the resulting negatives – whether curved or lying flat, depending on the lens design – have high levels of sharpness and balance. If there were no curvature in the COMPLAN during exposure, the negative would be out of focus at the narrow edges. From 1970 onwards, the newly calculated MINOX lens with a flat plate was used. The B model was fitted with this lens in a small production run as late as 1972 and was otherwise built with the Complan (a ‘MINOX B’ is, in contrast to the ‘COMPLAN B’ which can be found in vast numbers, a rare collector’s item! Similarly, a ‘COMPLAN C’ is a very rare piece!).
So now, please switch on your physics brain: if the curvature during exposure serves to produce a sharp negative, then the negative remains sharp even when it lies flat again, because the curvature merely compensates for edge blurring at the moment of exposure. What on earth is supposed to cause distortion later on during enlargement??? Once sharply exposed and developed, that’s it!
It’s exactly the same with enlargers. Up to a certain year of manufacture, enlargers were built with curved pressure plates. Why the switch to flat plates took place later on is not written down anywhere, but it’s obvious! They probably used second-choice camera lenses that had failed quality control for the enlargers. Or perhaps even the first-choice ones. In any case, these were also 15mm lenses with a fixed aperture of f/3.5.
If the enlarger’s contact plate is curved, this most likely means that a COMPLAN is fitted. In this case, the curvature of the contact masks simply compensates for the edge-sharpness issues inherent in the design of the built-in enlarger lens. This has nothing to do with the original image, but is solely a compensation within the enlarger’s optical path.
What can, of course, be problematic is if you use a flat mask with the Model III enlarger (which comes in both variations) fitted with COMPLAN optics. I don’t want to deny that this has happened in the past and resulted in out-of-focus prints – in which case the conclusion may have been drawn that a negative photographed with a COMPLAN MINOX can only be printed using a curved mask. Otherwise, this assumption is complete nonsense.
Regards, Marcus
max
Hi Marcus,
That explains why I’ve never had any problems ;-).
My question is more about the distortion. If I’ve understood the theory behind the Complan lens correctly, it’s not only matched to the curved surface at its focal plane (or barrel), but also to the image itself (otherwise it would compress the image horizontally).
Best regards,
Martin
cfb_de
Hello Max,
Normally (i.e. *always*), camera lenses are designed so that the negative removed after exposure can be easily contact-printed.
This requires the basic capability of a contact print to be ‘flat on flat’.
In very few cases, there were enlarger manufacturers with lower or far higher standards:
- Minox, because for a while they had nothing else (and the standards there are extremely high)
- Beseler, because you can make more money with rubbish than with gold
- Alpa, because deviating from the norm was considered modern
Have I forgotten any serious enlargers with a ‘crooked’ negative stage? That’s right. There were more in the budget market. But even back then, nobody used them with a proper lens.
Best regards,
Franz
Andreas_23
Hello
and many thanks for all the helpful tips on handling Minox negatives. It seems there are more Minox enthusiasts on the forum than I had thought.
I’d like to share my experiences today.
I have a Minox C with the Complan lens. I used Agfa Copex film and developed it in the Minox daylight developing tank with SPUR Nanospeed. The set (film plus special developer) is available from Mirko. I set the camera to the recommended speed of 25 ASA.
When making full use of the rooms, I achieve a maximum distance of 60 cm between the lens and the photographic paper with my Opemus 5. With a 50 mm lens, this results in a print size of just 9 x 12.5 cm. That’s not exactly thrilling. Okay, you can of course project onto the floor, which makes the image larger, but it gets darker and darker.
I was very lucky to be able to buy an Anaret 4.5/30 mm with a suitable lens mount for the Opemus on eBay for very little money (see photo). The Anaret is a tiny lens with a lens diameter of perhaps 7 mm. The mount looks a bit oversized, but it has to be that big so that the aperture ring protrudes from the lens mount at all.
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With the 30 mm Anaret, I can achieve a maximum of 16 x 22 cm. That is, after all, a 20x enlargement and is likely the limit of what can be expected from this 4-element lens.
As the Minox film curls up significantly after development (why is that, actually?), I initially simply placed it between two glass plates to ensure it lay flat. However, after finding Newton’s rings on all the images, I quickly abandoned that approach and made myself a negative holder, as Martin described it. This then fits into the glassless 35mm mask. It works a treat, though inserting the first and last frames of a film strip is a bit fiddly, as they still need a bit of support at the end of the film. As the Minox film has no perforations to grip, you absolutely must wear thin (cotton) gloves when handling the film, otherwise you’ll inevitably end up with fingerprints on the negatives.
Well, then there’s the problem of exposure time. Basically, you’d need a different condenser that focuses the light more intensely. So, with a double stop (to f/8) on 13 x 18 Ilford MG IV, exposure times range between 1 and 2 minutes. Patience is therefore required.
But the results make up for everything. I hadn’t photographed with the Minox for a long time and back then had sent the (colour) negatives to a specialist lab. The photos weren’t that great, which I put down to the tiny negative format at the time. What I saw now after fixing left me truly speechless. It’s hard to believe that you can produce such fantastic images from Minox negatives. The claims in Mirko’s catalogue regarding the Copex/SPUR Nanospeed combination are entirely accurate. Even at the largest print size (16 x 22 cm), I obtained very sharp and extremely fine-grained images with good gradation of grey tones. Unbelievable! Of course, this requires perfectly sharp exposures, because at just 25 ASA you quickly reach exposure times where the negatives start to shake.
Best regards,
Andreas
Andreas_23
Hello!
I’d like to add the following:
The lens has a small M 23.5 thread.
You need the special mount to achieve the short distance between the lens and the negative required for this focal length. Otherwise, you’ll have problems focusing.
The mount originally had a larger diameter. It may belong to a different model. I had it turned down to the correct diameter at a metalworking shop. That is why you can see the aluminium at the edge of the mount in the photo.
Best regards,
Andreas
