Sony PJ790 Still Camera Quality - AVS Forum
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post #1 of 6 Old 06-24-2013, 06:44 PM - Thread Starter
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Hi all,

So I just bought the Sony HDR-PJ790 and I love it.

I have a question about image quality for the still images.

I currently have the Sony A35, which is a 16.1 megapixel camera (sorry to anyone who read my last thread where I called it the A65, I was way off in my guess lol).

I was hoping that I would be able to get great quality photos on my new PJ790 so that I wouldn't have to carry around my A35 for photos and my P790 for video.

I know that megapixels are not the ultimate decider of image quality, and I'll admit that I don't know that much about the specifics of what makes an image of higher quality, but if I'm not mistaken, shouldn't I be able to zoom in on a photo taken with the 24.1mp PJ790 on photoshop "further" and crisper than I would with the same photo taken on the A35 (16.1 mp)?

The reason why I ask is because - look at the picture attached. The top photo was taken with my A35 and the bottom with my PJ790. These are zoomed in, but not with the camera/lens; I just zoomed in on photoshop and printscreened both images.

See how the bottom picture (the PJ790) is much worse than the A35?

Is there any way to fix this? I ask because I often take my photos and then crop out sometimes even 1/4 of the photo to make a new photo, and I never have quality problems with the A35.

I must sound kind of dumb - I know I can't expect the quality of a camcorder's still photos to match/be better than that of a DSLR, but I'm just confused because I thought that this is exactly what more megapixels are for - for zooming in with increased clarity.

I'm just wondering if there's a setting or something I'm missing. It is shooting in the 16:9 24mp mode.

As a sidenote, I took a bunch of the exact same photos with the A35 and the PJ790 and was really impressed with the PJ790's "unzoomed" quality. It's also really cool to see my photos in widescreen, it actually makes a big difference over the A35 which does not shoot in widescreen mode (I think).

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post #2 of 6 Old 06-24-2013, 07:19 PM
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Of course, your DSLR has more manual control, depth of field, etc.

If just casual pictures for the internet, then won't matter. Large pics need to be scaled down to post, anyway.
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post #3 of 6 Old 06-25-2013, 04:09 AM
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well per sonys site the sensor has a pixel gross of 6650K pixels so im guessing its interpolated to 24mp. i wouldnt recommend zooming into it
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post #4 of 6 Old 06-26-2013, 06:13 AM
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Hi ovoxo - the APS-C sensor on your A35 is a lot larger than a little camcorder sensor (no matter how many pixels they cram onto it).

A smaller number of pixels on a larger sensor can still give you higher resolution than a larger number of pixels on a small sensor (see this article from gizmag for an explanation).

So your A35 will pretty much always shoot higher resolution stills than your PJ790. But the PJ790 will produce artifact-free video, something most APS-C cameras cannot do because of their poor "downscaling" from 16MP to the 2MP (or so) required for video.

Again, hope this is helpful.

Bill
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post #5 of 6 Old 07-12-2013, 01:57 PM
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When I take a screen shot (using Sony Vegas Pro 12) from a 24p HD video recorded on my PJ790V, I get (surprise, surprise) a 1920x1080 image.

When I put the PJ790V into still mode and take a snapshot, I get a 6544x3680 image.

IOW, apparently, the PJ790V's internal digital video stabilization requires about 9x more pixel space than still imagery. (Think of an eyeball with an image projected on the iMax retina. To ensure a stable image to the brain, the retina's screen must be much larger - and the brain focusses on a small rectangle as it moves around the larger screen.)

----

These measures are in raw pixel terms. What the pixels measure, and how the data is compressed, are other questions.

PS. Ovoxo, I would never measure image quality on a laptop/PC. Your image comparisons above are meaningless. When I test images/videos, I use my 52" Samsung at 1920x1080 at 60Hz.
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post #6 of 6 Old 07-12-2013, 02:08 PM
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The diagonals do not look that bad, it is mostly digital noise I'd say, and what may be lower color resolution. Bit-starved image. What is the size of the files from the A35 and the 790?

P.S. Nice antenna.
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