So you really want more pixels?

Discussion in 'Canon EOS' started by bobatkins, Sep 7, 2015.

  1. Canon can help...they've developed an APS-H size sensor with 250MP. Now all you need is a camera to put it in and a 1TB SD card.
    http://www.canon.co.uk/about_us/press_centre/press_releases/consumer_news/cameras_accessories/aps_h_size_cmos_sensor.aspx
     
  2. Yeah, I saw that today. I'd be able to shoot everything with a 24-70mm and just crop if I needed the 600mm :)
     
  3. So the question is: Which lens is capable of delivering the required resolution?
     
  4. Most of them. The pixel pitch is no smaller than that of most small digicams (in fact, at 1.5 microns, it's larger than many), so the lens doesn't need any more resolution than a digicam lens - except it would have to cover a larger field.
    The sensor would have a theoretical resolution of around 330 cycles/mm, which is certainly achievable by many lenses in the center of the field at apertures of around f4. That's about 2.8x the (theoretical) resolution of the EOS 5Ds.
    Even lenses that are far from perfect would still give sharper images on the 250MP sensor than they do on the 5Ds sensor.
     
  5. So the question is: Which lens is capable of delivering the required resolution?​
    People have been asking that same question since the original Canon EOS 1Ds was released and the same question rears its head again and again (1Ds MkII, Canon 5D MkII, Nikon D800, Canon 5Ds) and we're all still happily shooting with our nifty-fifty's.
     
  6. BTW the claim for this sensor that "it can distinguish letters on the side of a plane flying nearly 12 miles (18km) away" means nothing. I can do that with an EOS 40D, or even and EOS 10D as long as I have a suitable lens mounted on it (or it mounted on a suitable telescope).

    It's pretty much true that a higher pixel count sensor will give sharper images than a lower pixel count sensor of the same physical size, no matter what lens you put on it
     
  7. They clarify in a footnote that the letters were visible in an enlargement of 1/40000 of the frame.
     
  8. FWIW, 250 megapixels would be only 375 megabytes per image if you have a Bayer sensor where each pixel records 12 bits of dynamic range. A modest 16 gigabyte memory card would hold about 40 photographs, more than used to fit on a roll of film. However, given typical write speed you'd only be able to take one photo every two or three seconds. (Ye olde Kodak DCS 560 was about that fast back in the day)
     
  9. I'm sure such high resolution sensors are useful for some applications but for my day-to-day photography, it would be impractical to deal with such amounts of data. For a specialist camera, why not.
     
  10. I would anticipate that any camera using this sensor would be using CFast cards. While most CFast cards don't saturate the bus yet (except maybe for reads) , since msata SSDs are capable of it, with an actual demand for that kind of throughput, I suspect they'd be on the market quickly.
    That'd get you up to ~ 1.5 shots /second... aka a really good reason to shoot jpegs ;)
     
  11. They clarify in a footnote that the letters were visible in an enlargement of 1/40000 of the frame.

    That's an 80x80 pixel crop, but it still means nothing without know what lens was used. If it's a 100mm lens it's remarkable. If it's a 10,000 mm lens, it not that special. Given the right lens/telescope I can resolve the letters with an EOS 10D. Of course I'd be using more than 1/40000th of the frame (which would be 12x12 pixels) in that case!

    The slow frame rates are just a limitation of current electronics. That will get faster. Canon are saying that this is a specialized sensor for surveillance applications, which I'm sure it is. With any given lens it would make reading licence plates or identifying faces easier than with any current similarly sized sensor. However it does show we're no where near the limits of what will eventually be put in a DSLR (or MILC). I presume it's not good in low light at high ISO (or at least not much better than a typical digicam), and that's another challenge.

    It's worth noting that in their Expos, Canon have show "the camera of the future", their concept for what might be around in a decade or two. It uses a relatively modest zoom along with a very high pixel count sensor, getting effective telephoto images by selecting a small section of the full frame. You could then have a what's effectively equivalent to what might take a 10-10000mm lens on a current camera. The advantage of such high pixel count sensors might be the ability to crop and retain excellent image quality as much as generate ultra high resolution images.
     
  12. No matter what lens was used, the impressive fact is that you can read letters in a crop of 1/40000 of the frame. You could not do that on a 10D with the same lens, or indeed with any lens. Of course, you could use a longer lens on your 10D and be able to read the letters, but only by using a larger part of the frame. So it's "meaningless" perhaps, but still impressive.
     
  13. I'm not sure about that. Here's a 12x12 pixel block (1/40000th of a 10D frame). You can read the number OK.
    00dUMy-558430984.jpg
     

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