The 240mm Componon-S is good for a 180 x 240 mm negative. I hope it is also good for a 8x10" negative, that is 203 x 254 mm.
https://www.artisantg.com/info/Schne...1128153237.pdf
Can someone confirm ?
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The 240mm Componon-S is good for a 180 x 240 mm negative. I hope it is also good for a 8x10" negative, that is 203 x 254 mm.
https://www.artisantg.com/info/Schne...1128153237.pdf
Can someone confirm ?
I use a 210 Nikkor for 8x10. Pretty sure your Componon-S will be fine. Regardless, these focal lengths are short for 8x10 and thus the angles from the lens through the negative to the diffuser are wide. Be sure your lightsource is wide enough and the diffuser even enough to provide adequate illumination across the negative. Your are good to go. Carry on.
Thank you for the information
Expect quite a bit of falloff, so you're either going to have to grind a diffuser thicker at the center than the edges, or burn in the corners proportionately during exposure. It also seems that 240's, being shorter than "normal", need to be about one more stop down than longer lenses for optimal corner sharpness. Test for this; but I'd expect f/16 to be the sweet spot, rather than f/ll like with longer lenses closer to the film diagonal.
These seem to be a rather common lenses, vs the 240 Rodagon which fetches higher prices on the used market. I've tested my 240 Apo Nikkor, but have plenty of column height, so prefer my 305 or 360 lenses for 8X10 film due to their perfect evenness with the ordinary flat diffusion sheet. Basic burning-in of corners is no big deal in ordinary black and white printing, but can impose hell to do consistently in certain types of color printing.
No question in my darkroom my Componon 240mm is not as sharp at the corners on a 16x20 projection when examined with my Peak 1 magnifier, compared to my 300mm lens. The 240 appears 'just ok' but the 300mm is pretty amazing with exactly the same resolution at center and every corner.
However, I can't detect the difference in prints.
Attachment 214671
Drew's comments about light falloff are very true. Realize, when looking at these graphs, they are normalized to 100% on the X-axis. The U-max (1/2 film diagonal) is set differently for each lens. To compare both on 8x10 you need to alter the scale. For example the 300mm lens data is plotted as if it is projecting film with a 370mm diagonal.
Attachment 214672
Attachment 214673
I don’t see significant fall off with my 240 Rodagon. I even use a 210 for small enlargements from 810.
Print papers do not have any where near the resolution of film. This is partly why extreme high performance enlarging lenses are not always greatly beneficial. What is and can be visible is light fall off. Again, there are a long list of variables and factors that influence this. IMO, the proper way to deal with projection light fall off is to use a longer than typical or normal focal length enlarging lens and make sure the enlarger light source is properly configured and set up for the lens to be used and film size to be projected.
8x10 = 300mm or 360mm
5x7 = 210mm or 240mm
4x5 = 180mm or 210mm
That said, the needs of using a longer than normal focal length lens for projection enlargement often demands significant base board to projection head distance or a floor standing enlarger. Yet, most that do projection enlargements from sheet film insist on using a table top enlarger with the shortest focal length possible often due to base board to projection head distance limitations.
Bernice
It's there, Luis. The practical effect diminshes at smaller f/stops. People who shoot wide-angle lenses a lot might not notice the falloff in the print because the falloff of their taking lens itself tends to compensate for it, a fortuitous characteristic deliberately employed by some practitioners. Or a compensating diffuser might already be in place in the enlarger housing. But if you objectively compared this to what you get with a longer longer lens, with each respective lens at the same f/stop like f/8, the native falloff of the 210 and 240 enlarging lenses would be quite evident.
If this falloff doesn't bother you, Luis, then don't worry about it. But it would have been a deal breaker for me back in my high contrast Cibachrome printing days. Yes, I know big labs that used 240's for this very kind of work, but in turn they needed very aggressively contoured diffusers specific to individual lenses at certain f/stops, and then required a LOT of hot lumens to punch through all of that extra density making big enlargements. Grinding custom thick acrylic diffusers is a pain in the butt, but I've done it several times. And switching back and forth between different focal length lenses is so much easier to accommodate with a single flat diffuser, relying on various lenses of longer than normal focal length respective to film format, or at least in the "normal" range with modest corner and edge burning. For many of my projects, burning-in is simply not an option; I need the exposure light completely even to begin with.
For example, I'll use a 150 lens for 6X9 film, a 180 or 240 for 4X5, and 360 for 8X10, although my 305 Apo Nikkor will also deliver me complete evenness of field for 8X10 from f/11 down.
Fortunately, I have a very high ceiling in the room where my 8X10 color enlargers are, for sake of tall enlarger columns. My modified 5X7 enlargers are in a smaller room with a normal height ceiling, easier to keep warm in winter, where I do most of my 4X5 and MF printing, as well as film-specific work.
Right back to print goals, expectations and all related. Light fall off due to using a wide angle projection enlargement lens can compensate for light fall off of a wide angle taking lens, how good might this match be.. another long list of variables.
BTW, still of the opinion APO process lenses (APO nikkor, APO artar, APO ronar) often do better than enlarger lenses.
Then again how many image makers are that picky and care about these "details" today when field folder view cameras are pressed into projection enlarger duty using a tripod?
Bernice
Well, I can literally stand on top the vacuum easel of my biggest enlarger without deflecting the plane. It's that well built. But most people don't use machined steel easels weighing several hundred pounds. The colorhead itself requires a block and tackle to lift off for sake of any bulb change - gotta get to that task soon, once I'm certain my shoulder bursitis is fully healed. But in the meantime, the Durst L184 is quite competent for the slightly smaller color prints I'm doing at the moment. And yes, I'm "picky". All those seemingly little details cumulatively add up.
In The Beginning, I have read, most used the taking lens for projection
Some like corner failoff
Enlarging lens falloff equates to lighter corners, which nobody likes, unless you're talking about direct-positive paper like Cibachrome. But yes, there is that antique trick of using the same taking lens for enlarging itself - probably not the best idea in terms of mismatched optical performance, depending on the specific lens in mind; but if it works for someone, it works. G-Clarons would do it decently.
May come back in style...:)Quote:
Originally Posted by Tin Can
https://i.pinimg.com/originals/16/bd...9c6ed7215c.png
I think the option for faux mildew dots is already a standard cell phone camera app. You can tell that the above photo is not a real antique because the lady is rolling her eyes ..."Ya gotta be kidding, a new app again?"