please help me with my durst m800.

[chris77]

i have been reading about corner sharpness. and i followed the advice to scratch an x onto a neg, put it between glass holders and have a close look.

my enlarger is equipped with the 105mm condenser and a 105 mm Rodenstock trinar lens.
negative format is 6x7

have started working on big prints and found corner sharpness to be really bad even at f8, a bit better at f11 but not satisfiying.

testing with the "X" just now, lens wide open shows the same effect, so i guess its either an alignement problem or i am expecting too much corner sharpness?
as i also want to use it for even bigger prints (using liquid emulsion) this "error" will even be worse in the bigger scale..

i am relatively new to analog processing, so any advice how to continue the quest would be highly appreciated.
thanks in advance.

chris

 

[RobC]

wide open is no good except for seeing if all corners are out of focus equally. If they are then how can it be an enlarger alignment problem ?

You need to close down a couple of stops on most enlarging lenses to get sharp.

 

[Dr Croubie]

How big are 'big' prints, and how do you know that it's the enlarging lens and not the lens with which you took the photo?
Trinar are a fairly 'budget' lens in any case. You don't need the expense of an Apo-Whatsit for (most) black and white, but you might get better mileage from a regular Rodagon / Nikkor / Componon for not much more money than a box of paper...

 

[chris77]

How big are 'big' prints, and how do you know that it's the enlarging lens and not the lens with which you took the photo?
Trinar are a fairly 'budget' lens in any case. You don't need the expense of an Apo-Whatsit for (most) black and white, but you might get better mileage from a regular Rodagon / Nikkor / Componon for not much more money than a box of paper...

hello.
images taken with a mamiya 110 on a tripod. very sharp.
prints will be at least 30x40"

as you stated i found out about the quality of the trinar lens, and have just started looking for a schneider kreuznach componon.

i see that (like the other poster mentioned) all four corners are almost equally unsharp wide open i doubt it to be an alignement problem.

thanks
chris

 

[John Koehrer]

I seem to vaguely recall that Trinars weren't one of Rodenstocks better lenses.
Go with a Rodagon, Componon-S or EL Nikor.

I been wrong before. Shrug.

 

[darkroom_rookie]

Your 110 Sekor Z (a Gauss-type lens) should work great for murals in 25-30x range. Mounting it to your Durst is a whole other matter.

Something tells me you're in the UK. Try looking for a Fujimoto 450M enlarger, they're not expensive on the second-hand market. There are condenser and dichroic models, head swivels for wall projection, lens stage swivels as well for alignment purposes, glass carriers are easily found and it's built like a tank. A sturdy 4x5" enlarger is bound to work better for humongous murals from 6x7 cm format than your m800.

 

[chris77]

Your 110 Sekor Z (a Gauss-type lens) should work great for murals in 25-30x range. Mounting it to your Durst is a whole other matter.

Something tells me you're in the UK. Try looking for a Fujimoto 450M enlarger, they're not expensive on the second-hand market. There are condenser and dichroic models, head swivels for wall projection, lens stage swivels as well for alignment purposes, glass carriers are easily found and it's built like a tank. A sturdy 4x5" enlarger is bound to work better for humongous murals from 6x7 cm format than your m800.

well, i am on the other side of the canal, in paris
the fujimoto looks good, but i have invested enough in this project recently.
your idea to use the 110mm lens for enlarging pleases me and i am lucky to have a brother running a workshop for metal work. i will construct something to mount it.
why the m800 wouldnt be good enough for the job?

thanks for your input.
chris

 

[darkroom_rookie]

why the m800 wouldnt be good enough for the job?

For much the same reasons why a longer lens is better when print size goes up and up (and I'm specifically thinking about large mural work with a condenser enlarger). Less vignetting, better edge sharpness. An excellent book titled "The New Darkroom Handbook, A Complete Guide to the Best Design, Construction, and Equipment" explains it all in great detail. I've seen a M805 and, though not the same thing as M800, it didn't look to me as well built as a Fujimoto 450, which has a really well-conceived column that reduces vibration to a minimum.

 

[chris77]

For much the same reasons why a longer lens is better when print size goes up and up (and I'm specifically thinking about large mural work with a condenser enlarger). Less vignetting, better edge sharpness. An excellent book titled "The New Darkroom Handbook, A Complete Guide to the Best Design, Construction, and Equipment" explains it all in great detail. I've seen a M805 and, though not the same thing as M800, it didn't look to me as well built as a Fujimoto 450, which has a really well-conceived column that reduces vibration to a minimum.

hello darkroom rookie.
well, i have found a way to mount the 110mm mamiya lens to the enlarger and the result is ...
... absolutely fantastic!

sharp from corner to corner with the column extended to maximum (105 cm).
already useable wide open but two stops down and its more than i would have hoped for. very very sharp!
... and really bright.

about the durst. i like this enlarger. its really sturdy and well built. it has nothing to do with the 605 or similar models.
no alignement problem whatsoever. no vibration neither. a joy to work with, and with this great lens mounted to it i am going for 2 m^2 enlargement soon.

meilleures salutations
chris

 

[Dr Croubie]

hello darkroom rookie.
well, i have found a way to mount the 110mm mamiya lens to the enlarger and the result is ...
... absolutely fantastic!

Usually this is not recommended, but then most enlarger lenses are specifically tailored to be used in the <15x enlargement ranges where most enlarging happens.
Non-macro taking lenses are more suited to focussing at infinity or at least a few metres away.
But it sounds like you're doing some absolutely huge enlargements, where you're working in the range more suited to taking-lenses than standard enlarging-lenses.
The other option, although they're rarer, are the dedicated wide-angle enlarging lenses, ie WA- or G-Componon, Rodagon-WA or -G.

But if you're getting results you like with the mamiya, then I'd stick with that.

 

[chris77]

Usually this is not recommended, but then most enlarger lenses are specifically tailored to be used in the <15x enlargement ranges where most enlarging happens.
Non-macro taking lenses are more suited to focussing at infinity or at least a few metres away.
But it sounds like you're doing some absolutely huge enlargements, where you're working in the range more suited to taking-lenses than standard enlarging-lenses.
The other option, although they're rarer, are the dedicated wide-angle enlarging lenses, ie WA- or G-Componon, Rodagon-WA or -G.

But if you're getting results you like with the mamiya, then I'd stick with that.

thanks for the input. i am aiming at 30x + enlargements.
and as for the G-lenses (havent checked the WA) they are far too pricey atm.
so actually i am really happy with this solution for now. thanks everybody..
chris

 

[darkroom_rookie]

[...] as for the G-lenses [...] they are far too pricey atm.

And that's an understatement!