aperture setting for enlarging lens

Discussion in 'Darkroom Equipment' started by billie williams, Jun 9, 2011.

  1. billie williams

    billie williams Member

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    hi. i have an omega d2 and use a 135 lens for my medium format negs. but in order to get more time to deal with dodging and burning, i tend to close down the aperture to f16 or even f22. is this okay? it feels like a dumb question, but as a newbie, i feel uncertain of myself. thanks for the help!
     
  2. MattKing

    MattKing Subscriber

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    Which lens are you using?

    Most enlarging lenses have a "sweet spot" at about two stops down from the widest opening. So if you have a 135mm f/5.6 lens, you can most likely get the best response at about f/11.

    Most likely you needn't worry about f/16. And f/22 isn't likely to be substantially worse.

    If you have complete flexibility, f/11 would be a good target.
     
  3. Sirius Glass

    Sirius Glass Subscriber

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    Once past the sweet spot the diffraction starts to dominate and eventually softens the enlargement. Stay near the sweet spot.

    Steve
     
  4. billie williams

    billie williams Member

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    more info

    hi! thanks for the help. the lens is a schneider-kreuznach componon 5.6
     
  5. R gould

    R gould Member

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    Robin Bell, one of, if the, top printers in the UK reccomends closing the enlarging lens down all the way to give you more controll over the final print, and as he has printed for all the top names in the world of photography, if it is good enough for himthen it is good enough for me, so I tend to close my lens down all the way, and I have yet to see a difference,
    Richard
     
  6. tkamiya

    tkamiya Member

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    I have a D2 also and use it for medium format and 35mm enlargements.

    I wonder what kind of exposure time you are getting with more reasonable and common setting like f/8? I typically print at f/5.6 (my 50mm lens is f/2.8 max) or f/8 (80mm f/5.6). Maybe one stop smaller if I need longer time. Enlarging to 8x10, I get very comfortable printing time to do all the manipulations I want to do. I never had the need to go as small as f/16 or higher.

    What kind of light source are you using? I'm using 75 watts bulb which is standard on D2. Are you possibly using 150 watts? Are you printing small? Are your negs on thin side? Are you using contrast filter? (without it, timing will be about 1/3 of using a filter)

    Just today, I printed 8x10 from 35mm and my exposure was 35 seconds at f/5.6. This frame was little bit on dark side.
     
  7. Newt_on_Swings

    Newt_on_Swings Member

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    I have heard of people using ND filtration before the condensers to allow more time for dodging. And as posted above you can maybe change the wattage of your bulb.
     
  8. Ken Nadvornick

    Ken Nadvornick Subscriber

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    Another possibility is to use neutral density filtration between the light source and the negative stage.

    I have a Zone VI cold light with the Aristo V54 lamp. It is so bright (and I prefer printing smaller enlargements) that I was also forced at times to stop down the lens to f/22. To preserve the "sweet spot" mentioned above I purchased some large, inexpensive sheets of 1-, 2-, and 3-stop neutral density theatrical (Roscoe) filters from a local theater supply company. A custom cutout piece of the 2-stop material was then inserted and pushed my apertures back to the f/11 range for my preferred exposure times with a 150mm f/5.6 lens.

    This should also work nicely with a bulb and condenser enlarger. I'm now using an Aristo VCL4500 light source that is - by design - a much lower intensity device, so the filtration is no longer needed.

    Ken

    P.S. I see that 'Newt_on_Swings' just beat me to it...
     
  9. 2F/2F

    2F/2F Member

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    If you have a good lens, you can use it wherever you need to in order to get the times you want. There are certain f number settings that will give you better results than others, and these best settings will vary with the lens in question. But I highly doubt anyone could see the difference with a quality lens unless the magnification was very high (i.e. very big prints and/or very close viewing distances).

    It is personal preference, but I try to enlarge in "shutter priority mode." I aim for a rough time that will allow me to burn and dodge the way I need to, and use the diaphragm of the lens to get exposure close. Then I fine tune with time.

    It is far more important having your enlarger properly maintained and aligned than it is to always print at the sharpest f number setting, assuming you have a nice lens.
     
  10. hpulley

    hpulley Member

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    Try it for yourself! Do straight prints so you don't need to do any dodging or burning. Do wide open f/5.6, f/8, f/11, f/16, f/22, f/32 if you have it. Check the results for yourself, use a magnifier. Check edge/corner sharpness and illumination, center sharpness. You may find f/11 is the sweet spot or f/8 or you may find you can't tell the difference. Wide open may have corner illumination issues.

    With fast RA-4 paper I sometimes need f/16 or even f/22 to get a reasonable exposure time, especially with small paper. With small paper it isn't noticable to use f/16 or f/22, the results are just fine. With larger paper I can usually use f/11 and with dense negs even f/8.
     
  11. Martin Aislabie

    Martin Aislabie Subscriber

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    You need to give yourself enough time to dodge parts of the print during the exposure

    Almost all prints can be improved with a bit of dodging during the exposure followed by a bit of burning in as secondardy exposure(s).

    Depending on how much dodging a print needs will affect your printing time - but 20s is not an unreasonable place to start - its not too short (not enough time to get all the dodging steps completed) or too long (needlessly wasting valuable darkroom time)

    I dial in equal amounts of Y, M & C into my colour head, in conjunction with the mid ranges of appature (i stop down from wide open to 1 stop up from minimum) to get to about where I want to be with exposure

    Good luck and have fun

    Martin
     
  12. ndrs

    ndrs Subscriber

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    Ctein gives test results for some lenses in his Post Exposure. According to the table on pp 88-89, one stop down seems to be optimal, at least for the lenses tested. There are reasons to stop down more, of course.
    Post Exposure is now free, get it from http://ctein.com/booksmpl.htm.
     
  13. billie williams

    billie williams Member

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    wow! i love all this input. i'm going out to print this morning - but first i'll check the bulb strength and then i'll run a few tests to see how the images look at different exposures. after reading all of your comments, i think my time issues come from not enlarging my 6x6 negs very much. only to 6"x6". Anyway, you all have given me lots of food for thought and i will go print and let you know how it unfolds. many thanks for the help!!!
     
  14. ic-racer

    ic-racer Member

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    Printing f22 on that lens should not produce objectionable diffraction. You can test it easily by making a pirnt a f11 and see if you can see any difference.
     
  15. billie williams

    billie williams Member

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    hi all - okay, for starters, it was a 150 watt bulb! when i switched it over to 75 watts, things improved dramatically. i also print rather small - or i should say, don't enlarge all that much, sometimes. so that is a factor as well. now i'll make some tests. i sure appreciate all the input! billie
     
  16. Maris

    Maris Member

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    I use the same: Omega D2 and a 135mm (Rodenstock Rodagon) for medium format negs. When I watch the grain through my Paterson grain magnifier I see it is sharp with a tiny bit of flare at f5.6, very sharp at f8 and f11, soft at f16 and essentially unresolved at apertures smaller than that.

    It makes no difference if the enlargements are small and the grain structure is too fine to see anyway. Big enlargements, where the grain structure has to carry the impression of sharpness and detail, will suffer at small apertures.

    Another subtle problem with very small lens apertures is that the depth of field of the enlarging lens reaches up into the condenser system and any spots of dust up there will be imaged as out of focus blobs; usually in skies and faces, naturally.
     
  17. Ken Nadvornick

    Ken Nadvornick Subscriber

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    And I use an Omega D5XL and a 150mm (80s-vintage Schneider Componon-S) for medium format negs, and can confirm this observed progression exactly as described above, when using my 25x Microsight grain magnifier. I have performed this examination more than once with very consistent outcomes.

    Ken
     
  18. tkamiya

    tkamiya Member

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    I said this before but in case you missed it....

    When you print, do you use multi-grade paper? If so, do you use contrast filters? If you aren't using any filters, you get grade 2 equivalent but your exposure time will be awfully short.
     
  19. billie williams

    billie williams Member

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    hi - sorry i didn't respond sooner....yes, i do use contrast filters. the problem seems to have been the wrong bulb and it was exacerbated by my tendency to print med format negs rather small. thanks for the follow-up. :smile: