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I have a high-end digital video camera able to output a higher number of megapixels than my digital photo camera. This is true only when using the camera to take stills. Is there anything that's going to come back and bite me from using the still image feature on my video camera? Could there be benefits?

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Edit, Further info:

  • My camera can use an uncompressed, progressive scan format.
  • Camear gets very close to 18 megapixels, has shutter and iris control with some other still options as well.
  • I also do video editing and there are occasions where a higher-quality image of a frame would be useful to replace a freeze-frame.
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    \$\begingroup\$ I've bumped to Sony NEX-VG10 which specifications sounds like it would produce decent still images (though no RAW), but I've had hard time to find still image examples — great video examples though. \$\endgroup\$ Commented May 21, 2011 at 10:14

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While I don't think it is impossible to produce a video camera that could produce a good still, I also have yet to see a video camera actually do it.

I think there are divers reasons as to why:

  • Digital Video has, for a long time, been a low resolution format. Yes, the sensor is usually capable of much more than, say, 640x480, but what's going on is that the sum of a larger number of pixels at the sensor level is going into the output of a single pixel in the video format. This permits two things: 1) "better" light gathering capabilities of this output pixel, and 2) Increased perception of sharpness.
  • This increased perception of sharpness means that the optics on the camera don't have to be all that great. The optics are going to be made to get as much light as possible in 1/30s or 1/60s (or even 1/24s) to the sensor, and then permit the downscaling to "increase" the sharpness of the image. What might look just a bit fuzzy at the full 15mp (or whatever it is), will probably look just fine at 2mp (which is HD, btw).
  • Video is a continuous experience, and our vision takes the incoming video and tends to sum it over many frames. So lower-quality sensors can be quite acceptable. If the color isn't perfect in each frame, or if there's a bit of noise across the frames, etc., it really doesn't matter to a large degree primarily because our brains will average it out, and so as long as it isn't overtly horrible (or long in duration), our brains will take care of it. But look at a still from the recording, and it's going to be horrible. (To some degree, I think this is why we can accept video compression; as long as it isn't so obvious as to cause obvious blocking and other visual artifacting, our brains are happy to accept it as "close enough" and go with it.)
  • While the zoom range is quite nice (30x, 60x, 80x, etc.), you're dealing with an incredibly small sensor, and the fact that to get a stable image you need to have a shutter speed of at least 1/, which means high ISOs. Now look at a compact digital camera using a small sensor at ISO1600 and 300mm-equivalent. That image will look nasty.
    • Side note: whilst you could tell that digital camera to go back to ISO100 and hold the shutter open for a lot longer, there are many video cameras that aren't going to permit that option. Some do, but don't count on it. Which means even if you get that tripod, it's going to shoot at high ISO regardless of what you think it should do.

Now, professional level digital video cameras (like those used by major studios), are probably pretty good at giving the control necessary to get good stills. But you're also looking at good glass in front of the sensor, and the level of control is much higher as well. I'm sure the RED Scarlet does fine, but it also costs a very pretty penny, and may as well be considered a hybrid system that can do both photography and video.

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  • \$\begingroup\$ Nice answer. I do happen to have shutter control and some decent still frame options on this camera which gets around 18mp. How large are the sensors on a typical quality digital photo camera? These are 1/2 inches. \$\endgroup\$
    – Imagen
    Commented May 21, 2011 at 16:41
  • \$\begingroup\$ DSLR cameras will have a sensor that is between between 0.87 and 1.42 inches in width (22mm to 36mm). For comparison, the iPhone 3GS had a 1/4" sensor. See en.wikipedia.org/wiki/Image_sensor_format for more camera sensor size information. \$\endgroup\$
    – Sean
    Commented May 21, 2011 at 23:44
  • \$\begingroup\$ I would mention that when shooting on a hybrid-DSLR (such as the Canon 550D, 7D, 5D etc.) Then using the shutter-release button whilst recording will save a higher-resolution image to the SD card. However this is at the expense of a second or so of footage capture and it will not be at the 'normal' full resolution of the camera. \$\endgroup\$
    – nchpmn
    Commented May 22, 2011 at 1:58
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From my experience the still shot capabilities on video cameras leaves quite a bit to be desired. That is, the quality is very poor. Your question asks if you can create high quality stills on your video camera, and the answer to that would be, it depends. Yes they can be high resolution(Megapixels), and they might even be higher resolution then your point and shoot still camera, but from my experiences they are poor in color, contrast, and to some degree sharpness.

One advantage many camcorders do have is that many times they have a very wide focal range, often extending into many 3-500mm of zoom. This can be quite nice, but to get a good still image you will likely have to use a tripod.

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  • \$\begingroup\$ I had assumed that I would need a tripod for the same reason I try to use one during photo shoots when possible, chance of line bleed from unsteadiness. Does the reason go deeper than that on video cameras or are you saying "slighter" unsteadiness is more exagerated on video cameras? \$\endgroup\$
    – Imagen
    Commented May 21, 2011 at 16:49
  • \$\begingroup\$ If you zoom in to 500mm on a film camera, DSLR, or video camera to take video OR stills, you are going to want a tripod to get good results. The farther you zoom in the more the effects of hand shaking or any subtle movement will be shown. \$\endgroup\$
    – dpollitt
    Commented May 22, 2011 at 20:38

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