Resolution of a Scanned file vs. Digital from a camera

Discussion in 'Digital Darkroom' started by leon chang, Dec 4, 2006.

  1. The images I scan on my Coolscan V have a resolution higher than that of a 8 mp
    D-SLR. This would in theory mean that I can make larger prints. How about the
    dynamic range a scanner like the Coolscan picks up, vs. the DR of a 8 mp D-Slr?
     
  2. There is no pedantic answer to this question, as demonstrated time and again in the (gratefully diminishing) film vs digital debates. If film meets your needs, there's no reason to jump ship. However, there must be a reason film SLRs are disappearing, film manufacturers are bailing out, and ordinary citizens can afford (used) Hasselblads.

    Perhaps the best approach is for you to rent an high-level DSLR for a week, put it through a workout and compare your results. Those of us who have undergone this process aren't shooting much film these days.
     
  3. Dynamic range of a Digital Camera and positive film are in the same range. Dynamic range of color negative film is larger. I scan color negative film with a Nikon 9000 and also have a Nikon D200. I don't shoot much film, but have excellent prints from scanned color negatives.
     
  4. In general slide film is worth about 5-6 mp per sq in, microfilm a lot more maybe like 12-15mp per sq in, 400 film more like 4-5, 800 film around 3-4.

    DR depends on the d camera and film. The Kodak slr cameras have a huge DR, canon 20d blows out pretty easily. E100G slide film has a little more latitude than Velvia, and also a Canon imo, but not some other dslrs.

    If you want to get down to the nitty gritty, then its best to do a few tests. An exposure strip will tell the DR tale. If you really want to compare resolution and not meaningless mega pixels shoot a resolution chart with each for comparison. Most of the dslr cameras have lp/mm resolving number listed somewhere on the net, then its simple if you want to print at 4lp/mm. The same is listed for film here and there but in general most of the time sharp slide film will be around 65-80lp/mm depending on all the shooting factors and EQ.
     
  5. Actually, the dynamic range of a DSLR is about 7 f/stops. This compares to a range of 3.5 stops for Velvia up to 5 stops for Provia. Color negative film ranges from 8 stops for Reala to 10 stops for NPS160. DSLR data is from DPReview and the film data is derived from the characteristic curves published by Fujifilm. Kodak films are similar.

    DSLR capture is sensitive to overexposure, although not as sensitive as reversal film. As with reversal film, one "exposes for the highlights" and lets the shadows take care of themselves. In reality, correct exposure for film or digital is a matter of placement, and depends on the subject and intent.
     
  6. If you prefer to work from film originals continue to do so.

    What you are comparing of course is like countingt the number of grains of sand on one
    beach
    compared to another as a measurement of how good your vacation will be. As Edward
    points out, the
    answer isn't straight forward and for various reasons.

    1.) a scan is a second generation image --and there is always some degradation of image
    quality in some ways when you work from a second generation image, and you add the
    optical-mechanical characteristics of the scanner and software as well introducing the skill
    with which the scan is made as a variable.


    2.) Print size. Small size prints need higher print resolution than larger print sizes as you
    look at them from a closer distance than you do larger prints --unless you are "pixel
    peeping". As long as you have enough pixels, and are working within the working
    resolution output range of your printer --Bruce Fraser and Jeff Schewe have proven to
    their satisfaction after extensive testing that this input range for the high end Epson
    printers this range is from 180 to 720 ppi -- then the resolution of the image measured
    in pixels per inch may not be as critical as once thought.

    3.) Interpolating an image from a digital camera, especially if working fro ma raw image
    instead of an in camera produced JPEG or TIFF yields better results than working fro ma
    scan.

    About "Dynamic range". Do you work a lot with images that have a very high dynamic
    range to begin with? Some color negative films may have an inherently larger dynamic
    range to begin with but that doesn't mean that a.) you are necessarily exploiting all of the
    potential
    range or b.) That your scanner/software/ color space and bit depth per channel
    combination can capture it in a
    single scan. If your scanner doesn't (most are limited to something less than a DR of
    4.0) to get all of that range into the system you'll have to scan twice.


    Also --and this is both the most subjective and the largest consideration -- what are you
    intending to do with your photographs?
     
  7. I normally do large prints on an inkjet. A3+. My Coolscan gives very good prints.
     
  8. Please do an archive search as similar questions have been asked many times.
     

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