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  1. #1

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    Enlarging Lenses - Optimum Magnification

    I'm looking for information on enlarging lenses' range of magnification and optimum magnification.

    So far I have only found concrete data for Rodenstock lenses. I'm interested in any data for the 240 and 300 mm Componon-S and 240 and 300 mm El-Nikkor lenses, though I realize data for the El-Nikkors may be non-existent.

    The only Schneider literature I have states a magnification range of 2-20:1 for the Componon-S lenses (an optimum magnification is not given); I suspect this is true for shorter lenses (i.e. 80mm) but inaccurate for lenses over 210mm which might have a range closer to 2-10:1. The G-Componon data sheet I have gives a range of 15-40:1 with optimum magnification at 20:1. In both cases the figures are for the entire group of lenses, not individual focal lengths.

    Thanks for your help.

  2. #2
    Mick Fagan's Avatar
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    I don't believe Schneider have ever given out any absolute magnification factors, concerning where their enlarging lenses are positively focused.

    However if you work backwards on the basis of 12x16" or 40x50cm paper enlargements, with slight cropping to have a borderless print, then you should be close to the optimised enlargement magnification factor for most format sizes.

    The 12x16" paper size is the most common size used after 8x10" paper and the one size in the middle of two other of the most used paper sizes internationally, 8x10" and 20x16".

    I have three Componon S lenses, 50 to 150, I believe that they all work best at or around 12 to 17 times magnification with their optimal being around 14 to 15 times magnification factor. My 150 lens though, probably works best at or around 5 to 8 times enlargement

    35mm works well on either 8x10", A4 (best) and/or 12x16" paper. 4x5 works well on either 12x16" and/or 16x20". 8x10" works well on 16x20" or 24x30" paper.

    These are the paper sizes that those formats were mainly enlarged to, therefore most enlarging lens manufacturers would ensure that their lenses worked well at these magnification factors. If they didn't perform with these paper sizes, then people would have stopped buying them.

    Mural sized enlargements, are another matter.

    Mick.
    Last edited by Mick Fagan; 09-28-2008 at 08:50 PM. Click to view previous post history. Reason: Left out last minute changes when importing from word.

  3. #3
    resummerfield's Avatar
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    Here are 2 scans from a 1983 Nikon El Nikkor Enlarging Lens brochure. It features the older lenses, but I think the later “N” lenses have the same construction. In my experience older and newer 300 El Nikkors seem to have identical interior construction, and performance.

    I scanned these at a high resolution, but the attachment process of this forum reduced the resolution.
    Attached Thumbnails Attached Thumbnails ElNikkor 1.jpg   ElNikkor 2.jpg  

  4. #4
    ic-racer's Avatar
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    Quote Originally Posted by H. G. Hart View Post
    The G-Componon data sheet I have gives a range of 15-40:1 with optimum magnification at 20:1. In both cases the figures are for the entire group of lenses, not individual focal lengths.
    .
    Looking at this datasheet it does look to me like even the very long G-Componons are optimized for 20:1 enlargement. The chart does not list data for anything less than 15:1 enlargements for the whole G-Componon series.

    http://www.schneiderkreuznach.com/ar...g_componon.pdf

    The 300mm Rodenstock I am using now is claimed to be suited for 2x-8x optimized for 4x. I know from experience that it does develop a distinct curvature of field when at 1:1 and doing reductions. This makes me think those G-Componon 300mm lenses may be unsuitable for home darkroom use. Perhaps tinkering with the element spacing could re-optimize them to 'more human' 2x to 4x (which is, of course 16x20 to 32x40).

  5. #5
    Martin Aislabie's Avatar
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    Don't enlarger lenses (good ones) even when used well away from their optimum out resolve photographic paper by large factor

    Unless you are doing something realy huge isn't the limiting factor the paper you print on ?

    Martin

  6. #6
    ic-racer's Avatar
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    Quote Originally Posted by Martin Aislabie View Post
    Don't enlarger lenses (good ones) even when used well away from their optimum out resolve photographic paper by large factor

    Unless you are doing something realy huge isn't the limiting factor the paper you print on ?

    Martin
    In some cases, you are correct. However, one problem is the effective apertures used in enlarging lower the resolving power to near that of paper. ie 20x enlargement at f8 = f168.

  7. #7

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    Quote Originally Posted by resummerfield View Post
    Here are 2 scans from a 1983 Nikon El Nikkor Enlarging Lens brochure. It features the older lenses, but I think the later “N” lenses have the same construction. In my experience older and newer 300 El Nikkors seem to have identical interior construction, and performance.

    I scanned these at a high resolution, but the attachment process of this forum reduced the resolution.
    Thank you, this was extremely helpful.


    For posterity here is my own anecdotal information on Rodagons:

    At three times magnification the 300 mm Rodagon is obviously sharper than the 300 mm Rodagon-G; at 8:1 the Rodagon-G becomes somewhat sharper. I've never had occasion to make an enlargement bigger than 64x80". This corresponds with data sheets I have that give a range of 2-8:1 for the Rodagon and 8-30:1 for the Rodagon-G.

    I'd be interested to make comparison prints for the 240 mm El-Nikkor, 240 mm Rodagon and 240 mm Componon-S at 3:1 (the size I most commonly print at).

  8. #8
    Martin Aislabie's Avatar
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    I have a 150mm Rodagon-G and have wondered where the "sweet spot" is on the enlarging lens

    I know they were designed for large enlargements (hence the G for grand) but I am unsure how large is normal and how large is grand

    For a 150mm - is it also (as H G Hart suggests for a 300mm) at 8 to 20 times enlargement ?

    Thanks

    Martin

  9. #9

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    Quote Originally Posted by Martin Aislabie View Post
    I have a 150mm Rodagon-G and have wondered where the "sweet spot" is on the enlarging lens
    Rodenstock gives 10-40:1 as the range of magnification for the 150 mm Rodagon-G (20:1 is the optimum magnification).

  10. #10
    ic-racer's Avatar
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    Quote Originally Posted by Martin Aislabie View Post
    I have a 150mm Rodagon-G and have wondered where the "sweet spot" is on the enlarging lens
    Check the table at the bottom of this page, column "3"

    http://www.prograf.ru/rodenstock/enl...html#Rodagon-G

    Like stated in the OP, I have never seen a similar table for the Schneider lenses.

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