hi there.
given the light is not an issue (very powerful led)
how will such a lens perform when going 12x compared to a naturally suitable 210 or 240 of the same type.
negative size is 13x18 (5x7 inch)
would it be possible to use it wide open (f 6.8)?
any input welcome!
cheers,
chris
Should work fine, but I'ld stop it down a few clicks. Is this lens already installed on a horizontal enlarger? If this lens is on a 5x7 Durst, maybe Drew will chime in here as to the likelyhood of focusing that lens with the existing bellows and making a 60" image with that enlarger.
7 foot wide print. I assume horizontal projection.
Try it!
Tin Can
A shorter Rodagon G designed for 57 will still be optimized for the same magnification but would require far less extension and would perform optimally at a larger f stop giving shorter exposure times.
i just did 12 times with ordinary rodagon 210.
had to use several neutral grey gelatins to bring expose down to 7 seconds (!)
led changes the world of enlarging. but be careful with the magnifiyer. very harsh light.
stopping past f 8 brings up diffraction when doing such enlargement. all laser aligned.
will the rodagon-g 360 improve edge sharpness and (micro) contrast?
horizontal durst 138. making the huge lens work together with the lens revolver will be tricky but i will make it work.
I've done 60" wide prints from 5x7 using a 180mm f/5.6 Companon-S, stopped down to f/11 - and get sharp grain to the edges. Light source is a Heiland VC LED, powered down enough to give me 20 to 40 second(ish) green light exposures, plus 15 to 30 second (ish) blue channel exposures, which allows enough time to do my typical dodge/burn routines.
Chris...seven seconds? Are you masking these...or do you have really fast hands?
Hello. did 2 prints with this setup. print size is 200x150 cm which is in fact 11 point something times enlargement.Originally Posted by John Layton
doing 60" wide means horizontal? that would be 8times.
makes a difference i guess.
i get excellent center sharpnes, corners are sharp, but not grainsharp.
7 seconds without dodging, just a stop or two of burning. fast and steady hands
when working with handcoated paper long exposure times seem to eat contrast, 7 seconds is not enough though. was for first tests.
just to underline my basic question,
is a rodagon-g 360 an improvement? guess it has to be, no?
No, not for what you want. A 210 or 180mm Rodagon would perform better at 11x. Stopped 2 stops down from wide open. You do have a properly aligned enlarger and a glass carrier? If not you will never get optimal results!Hello. did 2 prints with this setup. print size is 200x150 cm which is in fact 11 point something times enlargement.
doing 60" wide means horizontal? that would be 8times.
makes a difference i guess.
i get excellent center sharpnes, corners are sharp, but not grainsharp.
7 seconds without dodging, just a stop or two of burning. fast and steady hands
when working with handcoated paper long exposure times seem to eat contrast, 7 seconds is not enough though. was for first tests.
just to underline my basic question,
is a rodagon-g 360 an improvement? guess it has to be, no?
Properly aligned means film stage to lens stage to baseboard.
hello bob!
tx for your reply.
enlarger is perfectly aligned on all levels using lasertool.
glass carrier of course.
center sharpnes seems to decrease slightly when stopping down two stops. but then again, what i do lack is a bit more of edge sharpness (all four corners equally decreased sharpness when wide open)
light is not an issue!
NO!!! Listen to what Bob said! A 360 is for 8x10 or larger. 5x7 requires a 180 or at most a 210 mm lens. If you have a 210 Rodagon, use it. It will handle 12x enlargement as well or better than a 360 G-Rodagon. And stop down 2 stops, you said your enlarger LED head had plenty of light! No enlarger lens is made to be used wide open. Also, if possible use a Unipla lensboard on the Durst, not the the turret.Hello. did 2 prints with this setup. print size is 200x150 cm which is in fact 11 point something times enlargement.
doing 60" wide means horizontal? that would be 8times.
makes a difference i guess.
i get excellent center sharpnes, corners are sharp, but not grainsharp.
7 seconds without dodging, just a stop or two of burning. fast and steady hands
when working with handcoated paper long exposure times seem to eat contrast, 7 seconds is not enough though. was for first tests.
just to underline my basic question,
is a rodagon-g 360 an improvement? guess it has to be, no?
Last edited by Luis-F-S; 29-Dec-2019 at 23:21.
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