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  1. #1
    Join Date
    Jul 2008
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    6

    sharpness issue with Canon SD850 (ixus 950)

    Hi everyone,
    it's my first post here and I would need some help. I'm a modeller and recently changed my sony DSCW-17 for a Canon SD850 (Ixus 950 here in Europe). All pics of my models are taken in manual mode (P), with: a tripod, macro on, tungsten light setting and without falsh . The issue I have with this new camera (that I never had with my good old sony) is the sharpness of pictures. Take a look (and don't laugh about the object

    a pic taken with canon


    and for comparison one taken some time ago with the sony (the only difference is the white background)



    I know canon sd 850maybe it's not a perfect camera for that type of use but I use it also for standard family pictures and the one I had before was doing just great.
    this canon camera really let me down as in all reviews I found it was just great.
    I don't know if there is something I could do about getting sharper pics. I made a test with a borrowed Sony DSCW 120 last night and I didn't have any problem of sharpness at all.

    thanks for your help
    spit

  2. #2
    Join Date
    Jan 2008
    Location
    western US
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    1,218
    Wonderful models! Does the Canon let you set compression? If finer compression is not available, then I would simply try the next larger image size.

    Kelly Cook

  3. #3
    Join Date
    Jul 2008
    Posts
    6
    hi, thanks, this is the fine setting and the biggest size of image... I can't do better.

  4. #4
    Join Date
    Jul 2008
    Posts
    1,087
    Hi spitfire, welcome to the forums. It looks like the camera you're using (the Canon) is forcing a very large aperture, due to lowered light settings.

    What this is doing is making the part of your model that's in focus restricted to a small portion, instead of the full model - it's called depth-of-field.

    The larger the aperture (smaller f-number) the lower the depth-of-field. The smaller the aperture (higher f-number) the higher the depth-of-field. For your pictures, you want the second one.

    Unfortunately, I don't think there's a way to manually control the Aperture setting, but there may be a way around this. Try either increasing the ISO sensitivity and/or increase the lighting. This MAY help, or it may not, it may just force your camera to a higher shutter speed instead.

    If more light doesn't help, your next step would be to probably try the CHDK hack and see if you can set camera settings manually.

  5. #5
    Join Date
    Jul 2008
    Posts
    6
    Quote Originally Posted by jekostas View Post
    Hi spitfire, welcome to the forums. It looks like the camera you're using (the Canon) is forcing a very large aperture, due to lowered light settings.

    What this is doing is making the part of your model that's in focus restricted to a small portion, instead of the full model - it's called depth-of-field.

    The larger the aperture (smaller f-number) the lower the depth-of-field. The smaller the aperture (higher f-number) the higher the depth-of-field. For your pictures, you want the second one.

    Unfortunately, I don't think there's a way to manually control the Aperture setting, but there may be a way around this. Try either increasing the ISO sensitivity and/or increase the lighting. This MAY help, or it may not, it may just force your camera to a higher shutter speed instead.

    If more light doesn't help, your next step would be to probably try the CHDK hack and see if you can set camera settings manually.
    that's a great answer there jekostas, I will try to give more light and or play with Iso. If it doesn't work... ebay is already waiting this particular canon....

    thx spit

  6. #6
    Join Date
    Jan 2008
    Location
    western US
    Posts
    1,218

    Question

    Quote Originally Posted by spitfire303 View Post
    hi, thanks, this is the fine setting and the biggest size of image... I can't do better.
    The review for the SD850 gives the max file size as 3.4 MB. So this doesn't jive at all with the 179 Kb file you showed. Possibly the camera was set for 3.4 Mb, but the shot was later resized downward? If so, the software doing that resizing could be suspect. There are different flavors to resizing. Even worse, resizing sometimes brings along recompression, and there are a lot of flavors of compression.

    If the original was the 3.4 Mb size, please post a link to that.

    Kelly

  7. #7
    Join Date
    Jul 2008
    Posts
    6
    I'm sure I uploaded de big file I think it's imageshack who did the resizing job itself

  8. #8
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    Jan 2008
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    western US
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    In that case we are shooting in the dark ....

  9. #9
    Join Date
    Jun 2008
    Posts
    158
    I would assume that spitfire noticed the softness while viewing full res photos on his computer. He then posted them to imageshack to ask the question. Also, if imageshack compressed both photos, one might assume that the same compression/resize algorithm was used on both images. I don't think we could point to software as the culprit here.

    If aperture is the true cause, you may try adjusting the distance to the subject and trying different zooms. Aperture is different at various focal lengths on these cameras. You might also try building a mini studio light box with some good lights. It may just come down to this not being the right camera for this job.

  10. #10
    Join Date
    Jul 2008
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    1,087
    Quote Originally Posted by tkbslc View Post
    I would assume that spitfire noticed the softness while viewing full res photos on his computer. He then posted them to imageshack to ask the question. Also, if imageshack compressed both photos, one might assume that the same compression/resize algorithm was used on both images. I don't think we could point to software as the culprit here.

    If aperture is the true cause, you may try adjusting the distance to the subject and trying different zooms. Aperture is different at various focal lengths on these cameras. You might also try building a mini studio light box with some good lights. It may just come down to this not being the right camera for this job.
    I specifically noted aperture because the photo linked showed a classic case of of a depth-of-field issue - that is, the point closest to the camera lens and in the middle of the frame is tack sharp, but anything further away gets blurrier and blurrier.

    In terms of the distance issue... well, compact lenses tend to have vignetting issues show up in macro shots if you start increasing the distance to subject, epecially when working with a lightbox. It's just the limits of the optics.

    If you like Canon cameras and don't mind a slightly larger camera, the A5xx and A7xx have full manual controls.
    Last edited by jekostas; 07-23-2008 at 10:54 AM.

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