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Can the other two cameras provide a better pictuer?

  1. Jul 23, 2009 #1
    I have a camera (Camera 1) that has the specifications: 3 mega pixel resolution, 10x optical zoom, 120x digital zoom.

    The camera can see an object which is 100 feet away from it. Now, I have two other cameras. Can the other two cameras also see the object? Will the object be less clear? Out of alll three cameras, which camera shows the object the best?

    Please show all work so I will know how toreproduce it. Thansk!

    Camera 2
    1500x digital zoom, 0.3 megapixels, 30x optical zoom

    Camera 3
    34x optical zoom, 800x digital zoom
     
  2. jcsd
  3. Jul 23, 2009 #2

    negitron

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    Digital zoom is crap. You can do the same thing in any graphics editor (and with better ones like Photoshop, you can do better). You gave no resolution spec for camera 3; based upon the other two, camera 1 is the superior however you should note that optical quality has as much to do with it as the digital end.

    Since you seem to actually have the cameras in your possession, I'd just do a side-by-side shoot and compare the results.
     
  4. Jul 23, 2009 #3
    Well I actually don't have the cameras in my posession yet. When you say that the optical quality has as much to do with it as the digital end what exactly do you mean?
     
  5. Jul 23, 2009 #4
    Also, why isn't camera 2 and 3 better than camera 1 since it has a larger optical zoom. I also am having trouble finding the megapixels for camera 3. How does megapixels become relevant to this problem also? Doesn't it depend just on optical zoom?
     
  6. Jul 23, 2009 #5

    negitron

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    I mean the lenses versus the CCD or CMOS sensor. You can have a 12 MP sensor, but if your optics suck, your image will suck, too.
     
  7. Jul 23, 2009 #6
    Last edited by a moderator: May 4, 2017
  8. Jul 23, 2009 #7

    negitron

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    It's 640 x 480 which is .3 MP, same as 2.

    1 is definitely the winner.
     
  9. Jul 23, 2009 #8
    Ok. Thank you. Now here is a question for you. If camera 1 has 0.3 MP, 34x optical zoom, and camera 2 has 10 x optical zoom, 3.0 MP, which camera provides the best picture? Why?
     
  10. Jul 23, 2009 #9

    negitron

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    The 3.0 MP, because even though it only has 1/3 the optical zoom, it has 10x the resolution. At max zoom, the 3.0 can produce an image about 3x sharper.
     
  11. Jul 23, 2009 #10

    rcgldr

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    Are you sure that camcorder 1 is 3 mega-pixel? A hi-def camcorder with 1920x1080 resolution is 2.0736 mega-pixel. Most standard def NTSC camcorders are 720x480 (0.9 aspect ratio pixels), for .3456 mega-pixel.
     
  12. Jul 23, 2009 #11

    russ_watters

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    By the way, assuming the 1x magnification field of view is the same for each camera, comparing the angular resolution of different cameras is the ratio of the resolution to the square of the magnification difference.

    In other words, a 3 megapixel camera at 10x optical zoom is equivalent in angular resolution to....

    3/(30/10)^2=.333 megaixels at 30x optical zoom. In other words, if you take the 3 megapixel image and use digital zoom (ie, just crop it), to get 30x total zoom, it will have .333 megapixels.

    So cameras 1 and 2 have virtually identical angular resolution.
     
  13. Jul 23, 2009 #12

    russ_watters

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    I don't own one, so I looked them up on Buy.com. Most digital camcorders these days also double as still picture cameras, with typical still picture camera resolution. 3 megapixel would actually be a pretty meagre resolution for a camcorder these days.

    That probably makes a diffrence too, since the sensor resolution is not the "true" resolution of the picture you get. A 3 megapixel sensor really gives you 1 megapixel, effective resolution, as the pixels alternate red, green, and blue. If you take a higher resolution picture and scale it down, you'll end up with individual pixels with all 3 colors in them. I don't know if camcorders actually do that, though....

    I may need to get myself a digital camcorder now, though. The optical zoom is higher than a typical point and shoot camera and would come in handy for taking high res pictures of the moon... For the last lunar eclipse, I used a 5 mp, 10x zoom still camera and the pictures are just too low a resolution to be very good, after cropping them.
     
    Last edited: Jul 23, 2009
  14. Jul 23, 2009 #13

    mgb_phys

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    Zoom range is a stupid unit for anything other than marketing.
    Remember 10x doesn't mean 10times magnification as in binoculars, it means the short end is 1/10 the focal lenght of th elong end.

    This lens is only 2.5x
    http://www.hardwarezone.com/img/data/articles/2008/2483/Sigma_Bigma.jpg [Broken]
     
    Last edited by a moderator: May 4, 2017
  15. Jul 23, 2009 #14
    I am sure that the specifications I gave are correct. I read them right off of a website that sells the camera which also had similiar specificatinos to what was written on my camera.

    Now, i am still confused about how I MATHEMATICALLY find out which camera will show a clearer picture. Keeping digital zoom out of the picture, which camera shows the best resolution in the second problem I asked? How can I find this using math?

    Here is the question

    If camera 1 has 0.3 MP, 34x optical zoom, and camera 2 has 10 x optical zoom, 3.0 MP, which camera provides the best picture? Why?
     
    Last edited: Jul 23, 2009
  16. Jul 23, 2009 #15

    negitron

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    Errrr, yes,. I knew I was forgetting something.
     
  17. Jul 23, 2009 #16
    Do you think multiplying the optical zoom by the megapixels will get the job done? Any ideas?
     
  18. Jul 23, 2009 #17

    turbo

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    There are LOTS of web sites that will help you compare compact digital cameras, and the people operating those review sites put countless hours into comparing features, optical performance, sensor quality, etc, etc. You're wasting time trying to get comprehensive answers here.

    Have you done any homework on this? For instance, do you know who makes the lenses for Panasonic's compact cameras? Hint: they are VERY well-respected in the field.
     
  19. Jul 23, 2009 #18

    russ_watters

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    [/URL] I'm not sure what you are getting at: zoom is the ratio of the new focal length to the standard focal length. Ie, a common slr lens has a 28-80mm focal length range or 80/28=2.8x zoom. That's highly useful for figuring out how much bigger your lens can make an object.

    The main difference is that in binoculars, the imaginig device is your eye, which has a fixed focal length, so all 10x binoculars give the same actual magnification. But while there is no real standard, cameras tend to have a similar 1x (unmagnified) field of view.

    The lens in that image you posted is intended to be very fast. That's a different issue entirely and not one the OP is asking about.

    [edit] Also, "the short end is 1/10 the focal lenght of the long end" isn't right anyway. A camera lens has only one focal length (unlike binoculars or a telescope, which have two. A camera has no eyepiece: the imaging device is placed at prime focus.
     
    Last edited by a moderator: May 4, 2017
  20. Jul 23, 2009 #19

    russ_watters

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    Um, yeah, I had an idea and I posted exactly what you needed to do to find your answer....and that wasn't it. This was:
    Hopefully, you can plug in your new numbers and figure out the answer to your new scenario yourself...
     
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