Sharpness of 4x5?

Discussion in 'Large Format Cameras and Accessories' started by stradibarrius, Feb 27, 2011.

  1. stradibarrius

    stradibarrius Member

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    I have made about 20 or so shots with my 4x5 and 180mm lens and the clarity and sharpness are amazing!

    Are 4x5 negatives actually sharper on a mm by mm basis or do they just look sharper because they are so much larger than MF? If mm by mm is not the correct way to ask the question then whatever method of measurement you chose.
     
  2. Christopher Walrath

    Christopher Walrath Member

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    The film is the same. You just have a negative image that is about 18 times larger than that in a 35mm negative.
     
  3. Ian Grant

    Ian Grant Subscriber

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    In theory Barry 5x4 or larger negatives aren't as sharp mm for mm, and that may often be the case in practice but because the degree of enlargement is so much less (for the same size prints) that more than compensates taking apparent final image sharpness way higher.

    Often 35mm and 120 lenses may have far higher resolution but LF lenses can be designed to give far better coverage/image circles at a slight expense to maximum sharpness.

    So take two similar FL lenses 35mm & 5x4 shoot some images then take a 35mm size portion of a 5x4 neg and enlarge it alongside a 35mm neg by the same amount and it's likely the 35mm neg will be sharper, with better resolution.

    Ian
     
  4. 2F/2F

    2F/2F Member

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    They are actually less sharp on a mm by mm basis. This is because the lenses do not need to be built to the technical standards of 35mm lenses, since the film is so large and thus is not typically blown up as much. To make an 8x12 print from 35mm, you make an 8x enlargement, which is the equivalent of enlarging a piece of 4x5 film to 32x48 inches (larger than most posters, and larger than most people ever print). To make an 8x10 print from 4x5, you make a 2x enlargement, which is the equivalent of making a 2x3 print from 35mm. Ever seen a 2x3 print from 35mm? They look amazingly sharp...perhaps even a tad sharper than an 8x10 print from 4x5 film, because 35mm lenses are generally sharper and have more resolution.

    So, 35mm is generally sharper mm to mm. But 4x5 is dramatically sharper when printed to standard sizes.
     
  5. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    You've discovered the magic of LF. Keep shooting!
     
  6. Ian C

    Ian C Member

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    Less Image Compression and Printing Magnification = Greater Print Resolution

    Using the largest negative areas of the same aspect ratio as 8” x 10” paper, the corresponding negative areas are:

    35mm: 24mm x 30mm = 720mm^2

    4” x 5”: 91.9mm x 114.9mm = 10,557mm^2

    Thus the 35mm image is compressed about 14.7 times more than the 4” x 5” image.

    When printed full frame with a 1/2" overlap top and bottom, the image (disregarding edge of carrier masking) is magnified:

    35mm: 9.6X

    4” x 5”: 2.49X

    This accounts in large part for the apparent greater sharpness in prints from 4” x 5” negatives compared to those from 35mm negatives even if the 35mm lens is somewhat superior in resolution.
     
  7. archer

    archer Member

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    Dear Barry;
    about twenty years ago, in a photo magazine, someone asked the same question and it resulted in one of the writers testing just that assumption. The test consisted of making negatives with 35mm, 6x6, 4x5 and 8x10 on the same film, with lenses of the same normal focal length for each format and of like quality. I believe the focal lengths were, 58mm for 35, 80mm for 6x6, 150mm for4x5 etc. The results were astounding. All the negatives were enlarged to the same degree for each format and even the lens for the 8x10, showed so little difference in sharpness and contrast compared to the 35mm lens that the conventional wisdom of sharper lenses for smaller formats seemed to be in serious question if not completely thrown into a cocked hat. I was very dubious so I performed my own test and compared my 50mm Summicron for my Leica against my 150mm Symmar S for my 4x5 and much to my amazement, the Summicron won the resolution test but by such a slight margin, I was shocked. The difference was no where as great as the manufacturers resolution numbers would suggest, but even more surprising was that the Symmar S easily won for contrast and actually looked slightly sharper at normal viewing distance. I know I'm not the only person to have seen the article and I hope others may recall the same information and add to this very interesting question.
    Denise Libby
     
  8. GeorgesGiralt

    GeorgesGiralt Member

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    Hello all !
    Actually, the lens resolution is not the only limiting factor one should consider when talking about resolution.
    One should also consider diffraction, contrast and the resolution of the film.
    The resolution figures are often quoted at two contrast : One high value 1:1000 or something like that, and a low value, 1:50 for example.
    So if you want to get the best from your film, you should light it with the highest contrast possible.
    If you want to get the best from your lens, you should use the lens opening which gives you the best contrast and resolution and stay away from too closed to limit the diffraction killing your image.
    (here I suppose film placement to be perfect in all cases)
    So in LF you will use your lens at f:16~22 to match all requirement above and light your film with around 60 pair of lines per mm.
    In 35 mm you'll be at f:8~11 to light your film with the 120 pair of lines per mm your best lens is capable.
    What if your film can't handle this resolution ? It is easier for film to reproduce less than 60 pair of lines per mm than it is to reproduce (with good contrast) the very demanding 120 ....
    So IMHO, in 35 mm the limiting factor is film and in LF it is the lens... This is more and more sensible as you go larger in format. I wonder if one can find an 8x10 lens apt to deliver 60 pair of lines per mm on the film.
    The position of MF is in between. this is why a Mamiya 7 negative is soo good !
    You can prove this in macro work. A medium format lens gives tremendous results an above 1:1 reproduction scale on the 4x5 film as does the 35 mm format lens (they cover this film surface at these magnifications because the lens is far from the film). Both are far better than their large format counterparts. Here, the 120 pair of line are spread on a length of film which make them visible. And the difference shows.
    Hope this helps.