Is it possible to get a 'sharp' picture edge to edge?

Discussion in '35mm Cameras' started by Scott, Jun 10, 2004.

  1. Scott

    Scott Guest

    Hi everyone,

    I've just completed a black and white workshop, and have mixed results.
    The 8x10s printed by me are ok, but not the 'tack sharp' I'm used to on the
    color 4x6s I get from the good lab. Now, before you start chortling, I know
    printing the same amount of information on a bigger area will result in some
    degradation. I would like to ask you, O' Fonts of Photo Knowledge, is it
    possible to get an 8x10 or 11x14 that is sharp edge to edge? I have
    reviewed MTF charts on the lenses I have (three primes, 28, 50 and 85 - all
    35mm format) and it seems that most if not all lenses have a definite loss
    of sharpness as the edge is approached. The near exceptions being the
    expensive glass, whose chart looks much like a horizontal line. So am I
    correct in saying that 1) all lenses to some degree lose sharpness at the
    edges, 2) one cannot get an 8x10 to be as sharp as a 4x6 without spending
    some serious cash on the glass and 3) one could combat this phenomenon with
    slower film, for increased sharpness, to a point. To summarize: is this
    lack of sharpness at the edges an artifact of the format and lenses, which I
    should ignore and go out and take pics, or am I doing something wrong? I
    did some pics of lens charts to test resolution, and even at the 4x6 one
    could see slight light dropoff and a loss of sharpness at the corners, more
    prominent on the 28/2.8 than the 50/1.8. Ideas?

    Thanks for helping an overworrier,
    Scott
     
    Scott, Jun 10, 2004
    #1
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  2. Nearly yes
    serious cash on the glass

    Yes. Generally macro lenses are designed to be sharp edge to edge.
    sharpness, to a point.

    No. Finer grain film will just reduce the overall grain and increase
    the possible sharpness, but it can's add what the lens does not capture.

    4) Is part of the problem possibly my enlarger lens.

    Yes.
     
    Joseph Meehan, Jun 10, 2004
    #2
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  3. Scott

    Nick Zentena Guest


    Other then using a larger piece of film? Ya first of all is the problem
    the print or the negative? Bad printing will screw up a good negative. Is
    the negative good? If not why? The more you push the limits the more effort
    you have to put into things. IMHO 11x14 from a 35mm negative is pushing the
    limits hard. But getting a good 8x10 isn't that hard. Not an 8x10 that will
    look equal to a 4x6 but a good one. So assuming the negative is good is
    something wrong with your printing setup?

    Nick
     
    Nick Zentena, Jun 10, 2004
    #3
  4. I've just completed a black and white workshop, and have mixed results.
    It may or may not be possible to get an 8x10 that is as sharp as a 4x6, but
    it is possible to get an 8x10 that shows no visible unsharpness when viewed
    without a magnifying glass. Let me suggest the following:

    1) Slow film. Kodak T-Max 100 is a reasonable choice.

    2) Stop the lens down to f/11.

    3) Use a tripod.

    Then print the resulting negative and see how you like it. If you're still
    not satisfied, use a magnifying glass to look at the film grain and see
    whether the grain (not the image) is sharp out to the corners. If not, you
    need to stop down your enlarger lens more or replace it by a better one.
     
    Andrew Koenig, Jun 10, 2004
    #4
  5. Sharp edge to edge? Unlikely, for a lot of reasons. The main thing is that
    a lens plane of sharp focus is not a plane, but a curved surface. Unless
    everything you're interested in lies on that surface, it will be to some
    degree unsharp. You can help matters by stopping down. This increases
    depth of field, making the plane of sharp focus thicker, if you see that I
    mean. Some lenses suffer from this "curvature of field" more than others,
    but they all do it with the exception of flat field macros. Cheap lenses
    are usually worse than higher quality ones.

    Since you haven't told us how the exposure was made (On a tripod? No? It
    should have been, if you're going to be critical of sharpness! What was the
    f-stop? The shutter speed?) further help is not very possible. It may just
    be that your small prints *were* unsharp, but since they were small, you
    didn't notice.

    Also, how were the prints made? Did you use a grain magnifier? If you get
    the grain in focus, that's as sharp as things will get.
     
    Mike Lipphardt, Jun 10, 2004
    #5
  6. Scott

    Gordon Moat Guest

    Sure, but all parts of the system from capturing the image, to printing the
    image, must be of the highest quality. Technique also plays into this, and the
    experience of the operator can help. If you only have limited experience doing
    your own prints, then it is indeed tough to get consistent results.
    Quite common with many lenses. Take a look at some of the more extensive MTF
    charts, and you might find that often f8 or f11 might be closer to what you
    want to achieve.
    Nearly all, with a few exceptions.
    Not entirely true. The enlarger lens now adds another variable. You are going
    to twice the enlargement in your comparison, so even with a good camera lens,
    and technique, if your enlarger lens is not used at optimum aperture, or even
    not that great an enlarger lens, then you will get worse results than the
    optimum.
    Not really. It might be enough of a difference that you are more satisfied with
    the results, but you could chase that direction for a while, especially
    considering how many films are on the market.
    You may just be super critical. If you are doing architecture, or
    photogrammetry, then there is nothing wrong with being super critical, but then
    I would say you are expecting too much of 35 mm format. You can look into some
    medium format systems that are more suited to extreme edge resolution, if your
    work requires that level of accuracy. However, if you go that route, you should
    also go with a much better enlarger system.
    Sounds to me like you may be doing quite a bit of tripod photography. Since it
    seems you are very critical, you might want to try using medium format instead.
    Once it is on a tripod, the slight difference in weight and added bulk of
    medium format may not be that noticeable.
    You may want to check more into enlarger lenses. Schneider and Rodenstock
    publish data on the MTF of their enlarger lenses, and you might be able to find
    a better lens. Some of these are okay to purchase use, so this is not
    necessarily an expense change for your system.

    When I was doing more architecture work, I found that for super critical
    sharpness, there were few 35 mm choices. Largely the choice of doing this with
    35 mm was more for documentation, the less intrusive nature of the gear, and
    the slightly quicker operation. I have used a Nikon 35 mm f2.8 shift lens for
    some of this. The advantage of a shift lens for 35 mm is that the image circle
    is much larger than it needs to be. When it is only slightly shifted, the
    centre to edge resolution on the final image is very even across the 35 mm
    frame.

    Depending upon what brand of camera you own, you may want to try to find a
    shift lens for it. They are slow to use, and not very convenient. It is also
    possible to make mistakes when using these, since there are many things to
    check while setting up each exposure. However, when doing critical architecture
    with 35 mm, it is nearly one of the only good choices, with few substitutes.

    The increased coverage trick can sometimes work on 35 mm, if you are able to
    adapt lenses from medium format or large format. Pentax, Contax, and some third
    party companies make adapters to fit larger lenses onto 35 mm bodies. While
    this is not a low cost solution, the results can be very good.


    <http://www.agstudiopro.com> Coming Soon!
     
    Gordon Moat, Jun 10, 2004
    #6
  7. Nope. Get a good 50mm 1.4 or 1.8, stop it down to around f:8 (not just for
    depth of field, but also because this turns out to be near optimal for
    many lenses for the 35mm format), focus carefully, and eliminate camera
    shake (use a tripod and remote release or self-timer, high shutter speed).

    Now you should have a decent negative. Next is printing. You need to make
    sure you enlarge with a good lens at its optimum aperture, mounted in
    an enlarger that holds everything in alignment (negative, lens and easel
    all parallel) and focus very carefully.

    The rest should be easy :).

    Normal lenses are often great bargains: cheap and sharp. Canon has
    their MTF charts on line; notice that both the 50mm 1.8 II and the 1.4
    USM are quite sharp at f:8 almost to the extreme corners. But wide
    open is a different story.

    <http://luminous-landscape.com/tutorials/understanding-series/understanding-mtf.shtml>
    might be helpful.

    <snip>
     
    Stephen H. Westin, Jun 10, 2004
    #7
  8. Good film for "real" use. Pan F is probably sharper; for the ultimate
    (in over-the-counter films) try Kodak Technical Pan - needs a special
    developer though. You would probably find these films a bit of a pain to
    use every day though.
    The best camera lenses should be giving their best at f/8 or even f/5.6.
    However, for camera lenses, there should be no noticeable fall-off by
    f/11.
    Yes. A solid one - and a cable release (or use the self-timer).
    If you have a good enlarger lens, then stopping it down more in an
    attempt to get more sharpness is doomed to disappointment*. A good
    enlarger lens (50/2.8 EL-Nikkor, Componon or Rodagon) will have its best
    performance at f/4 or f/4.5; stopping it down further will give
    significantly less resolution. Of course, you have to make more effort
    to focus accurately (and to check proper enlarger alignment) but
    resolution at f/4 is enough to give a sharp 10x8. Resolution at f/11
    will never be quite good enough. If your enlarger lens is mediocre, then
    I agree replacing it should be an essential step.

    *The effect of stopping down is more dramatic for enlarger lenses,
    because diffraction effects are much more serious. At 8x magnification
    and f/11 nominal, effective aperture as seen from the paper is f/88.
    This limits resolution to about 15 lp/mm; combined with degradation from
    other sources, this is very unlikely to give a sharp print.
     
    David Littlewood, Jun 10, 2004
    #8
  9. See my other post for comments on film and enlarger lenses.

    Taking Gordon's suggestion one step further, you should maybe consider
    using a 5x4 view camera. A good second hand camera and a selection of
    2-3 lenses will cost surprisingly little if you shop around. Film is
    very expensive per shot, but (a) you will take a lot less pictures, and
    put more effort into each one, and (b) you can, if you need, give each
    sheet individual processing.

    My 5x4 outfit cost a lot less than my 35mm one, and blows it away for
    quality. I use it less now largely because of back problems....
     
    David Littlewood, Jun 10, 2004
    #9
  10. Unalterable laws of physics demand that edge performance will ALWAYS
    be less than axial (center). It has to do with optics. The very best
    lenses (e.g., Leica APO macros and asphericals) have edge performance
    that is better than central performance of other manufacturers, but
    even these perform better in the center.
    Almost, but not quite.
    Yes

    2)one cannot get an 8x10 to be as sharp as a 4x6 without spending
    Yes

    3) one could combat this phenomenon with
    Are you using a Focotar-2 (Leica) enlarging lens? Glass carrier?
    Sounds like you need to set your priorities. If you want top quality,
    you're going to have to outlay some big cash.
     
    Michael Scarpitti, Jun 11, 2004
    #10
  11. Scott

    Bob Hickey Guest

    I have had a gang of enlarger lenses, most of them terrible. I now
    use a 75 mm Rodenstock or Fuji. I used to use a condenser enlarger and the
    bulb kept getting hot spots, which caused me to lose the edges. A dichroic
    head and a longer lens cured all. Bob Hickey
    WWW.pbase.com/bobhickey/galleries
     
    Bob Hickey, Jun 11, 2004
    #11
  12. Scott

    brian Guest


    Not true at all. Its entirely possible to design optics which have
    better performance off-axis than on-axis. Bear in mind that there are
    important classes of optics which are designed to work *only*
    off-axis. Dyson and Offner relay systems are two famous examples.

    Brian
    www.caldwellphotographic.com
     
    brian, Jun 11, 2004
    #12
  13. Scott

    Scott Guest

    I would like to thank everyone for their input. A lot of good advice was
    given and I certainly do appreciate it. This is what the group was known
    for back before the trolls and wars.

    Thanks again,
    Scott
     
    Scott, Jun 11, 2004
    #13
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