Measuring resolution

February 8, 2004  |  kathy rilea
6 Comment(s)

What impact does resolution have on file size?

Comments
  • Adam says:

    It depends on file format. If you double the horizontal and vertical resolution for an
    uncompressed file format it will make the file four times bigger. For compressed (both
    lossless and lossy) formats, doubling resolution in both directions will increase file size,
    but by no more than four time — exactly how big the increase would be will depend on
    the image and format.

  • Edward Tufte says:

    You can see the link in operation in some digital cameras by cycling through image quality (e.g., fine, normal, basic; NEF, TIFF, JPEG) and noting the resulting number of images available on the memory card. For example, on a Nikon D100, 1 GB memory card, set for TIFF, the cycle through fine, normal, basic yields 56, 101, and 221 images available.

    The manual for the camera may provide a table showing the links between image quality and file size.

  • Gene Prescott says:

    Most existing digital cameras utilize technology acronymed CCD. Generally, less than 100% of the pixels are captured with a processor interpolating the color, etc. between the captured and missing pixels. The Foveon X3 captures a unique red, green, and blue for each pixel. So an X3 capture generally is significantly larger in terms of file size than a CCD capture. None of the popular camera manufactorers are currently using the X3. Sigma has two professionally targeted models, the SD9, and, newer SD10. Polaroid (which is Polaroid in brand name only) is scheduled to release a consumer targeted camera, X530, this summer.

    Beyond the radically different capture techniques, the X3 is housed in a single CMOS chip, which means it can scale well in terms of manufactoring cost and physical size, and maybe more importantly, will also tend to consume less power than the more prevalent CCD technology. It is possible that the X3 will leap frog the traditional camera market and go for the cell phone/camera market (cost, size, and power.) Either way, CCD or X3, cameras will be evrywhere.

  • Edward Tufte says:

    To wander off this thread, it was surprising to see a lukewarm review of the SD10 in the recent Shutterbug, which usually gives enthusiastic reviews.

  • Gene Prescott says:

    To wander even further.

    While a few professional photographers are tepid, I believe most are in fact lukewarm and a few frigid regarding the SD9 and SD10. Because there are such differences in what the technologies do, megapixels is not a good unit of measure. So a lot of the rhetoric is about how to state equivalency as it relates to quality.

    Actually it is a major event for a professional photographer with a huge investment in legacy equipment (lenses, etc.) to change horses, so there is a certain amount of resistence regardless of relative quality.

    However since the SD10 natively generates a RAW file, a lot can be accomplished by a skilled photographer with good tools after the shoot. So far not many professionals have made the switch.

    If economies of scale cause the CMOS chip to be practical in most people’s cell phones, the output is apt to be better than the demand of most users. A bonus will be capturing 30 frames per second video with the same device. There will be multitudes of uses for that aspect of the X3 capability.

  • Gordon Richardson says:

    The original question is ambiguous, since digital images consist of pixels, and do not have an inherent resolution.

    If you plan to print an image at a particular size, then increased resolution requires an increased number of pixels, which increases the file size.

    The common Jpeg format has a tradeoff between quality and file size. If you interpret “fine-detail” as resolution, then increased quality will increase the file size.

    A good reference is: Display, Printing, DPI and PPI http://www.photo.net/learn/resize/

Contribute

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.