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What image quality and resolution should I use?

Hi all,

I have a Nikon D80. That means I can control 2 variables: the image resolution and image quality. (Resolutions: 10 megapixels (MP), 5.6 MP and 2.5 MP) (quality: compression 1:4, 1:8 & 1:16))

This means when I select 10 MP and a compression of 1:4, I get a highres image of 3.2 MB and when I select 2.5 MP and a compression of 1:16, I get a loweres image of 240 KB.
The difference is a file that is 14 times bigger!

I want to make a tradeoff between image quality; upload speed and processing time when 'synthing'.
Could you guys give me more insight? Is there an optimal?

Is is true that small files have in comparison a:
- faster upload
- faster download
- faster synth (less detail =? less calculating)
- slower synth (less detail =? harder to calculate)
- worse synthy% (less detail =? less information)

So if I do an panorama (e.g.:like here) can I use 'small' images for the panorama, and the big ones for the shots with much detail (zoom) for optimal performance/quality ratio?
(reducing the 1.5 gig upload to a 300 MB upload; but still maintaining some of the high quality zoom images)

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  • EMPLOYEE
    I’m glad to help
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    David Gedye (Principal Group Manager) August 24, 2008 18:10
    Great question! Here's the information you're looking for:

    The synther currently uses up to 1.5 megapixels of the photos it is given, so any resolution above that won't change your synthy score. If you downsample to below 1.5 megapixels you will definitely be hurting Photosynth's ability to connect the photos.

    Obviously, the lower the resolution the faster the upload. Other things being equal, if you downsample to half the pixels your upload will take approximately half as long.

    Downloading (viewing) is a different story altogether. Because of the Seadragon capability to get the pixel that you need when you need them, your viewing speed should be pretty much identical whether you have 1 megapixel images or 10 megapixel ones.

    We encourage people to synth their full resolution photos because the viewing experience is much better if you can zoom in and inspect all the interesting details, but I recognize that the upload times are really long. We hope to add some kind of a preview mode to get around this problem in the future.

    Hope this helps,
    David.
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  • IMHO the only reason not to have lengthy uploads is in case the output is not what you want. This is one reason for a preview before upload.

    IMHO it is import to have as many pixels as you can give it. The time to upload should not matter if the quality of the outcome is better. As David said the preformance of viewing is not impacted by the size. A one time sacrifice for a long upload with better quaility outweighs a short upload time with bad quality. To the viewer they don't know if it took you 1 hour or 20 minutes, but they will know the quaility of one is better over the other. Viewing the two different ones will have no performance impact just quality. I think this is also why we have 20GB of storage.

    But again the issue is not being able to preview which will then turn that half hour into wasted time because of a bad synth. I'm doing one right now that is about 80 images at 100MBs. I hope it turns out ok.

    Think of it like raytracing (Toy Story) I can have the computer spend one day to produce a high quality movie or one hour to produce a lower quality. But playing either movie will still play back in real time.
    • That is not exactly what I meant; although I agree with you ;-)
      I mean that, when you have some separate hi-resolution 'tiles' of intresting details, you can use a 20 MP image or a 1.5 MP image to 'stitch' / synth them together.
      In that case I think I prefer a 1.5 MP, because it is smaller; takes less space on the server (max. 20 gig for each person) and does the job, just as good :-)
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  • Well I think I was answering some of these questions base on the theory and feedback.

    Is is true that small files have in comparison a:
    - faster upload yes
    - faster download no difference
    - faster synth (less detail =? less calculating) I guess yes
    - slower synth (less detail =? harder to calculate) I guess no
    - worse synthy% (less detail =? less information) I guess yes

    the one left out is
    - quality lower

    I think there is some compression going on as well. Not that much can be done with JPG because they are already compressed.

    This is my opinion based on the theory and not practicla use. Except for the quality of a cell phone camera and a real camera. Guess which synth looked better? I appluad you on the effort, the feedback, and I'm sure it will help us. As you say there is no difference in quality but less storage. I could go the route I'm going of who cares about size. Then in about a week run out of room where as you will still be going.
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