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Video vs Photgraphy Frame Rate

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Matt Kelly
Video vs Photgraphy Frame Rate
on May 2, 2016 at 4:11:36 am

I've always been a bit curious by the design of frame rate in photography, especially since it's so much slower than video. Why does photography have the option to have burst shots, when you could just take a video? I see that you may want to have stills in separate files, but couldn't you just take screenshot stills from your video? In theory, you could have the option to have 60 or more stills in a second, rather than your typical 5-10 in photography. This would seem to render any sort of burst photography useless.


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Mike Smith
Re: Video vs Photgraphy Frame Rate
on May 2, 2016 at 5:51:46 pm

Yes, you could use video files from your camera in that way if you're happy with the video resolution and compression.


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Matt Kelly
Re: Video vs Photgraphy Frame Rate
on May 2, 2016 at 7:57:30 pm

How is the resolution and compression affected differently in video as opposed to photography?


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Mike Smith
Re: Video vs Photgraphy Frame Rate
on May 3, 2016 at 12:23:32 pm
Last Edited By Mike Smith on May 3, 2016 at 1:41:04 pm

When in video mode cameras will capture at much lower resolution - mostly in HD Video - 1920x1080,or around 2 megapixels - and some in variants of 4K , which might be 4096 x 2160 (roughly 8 megapixels) or 3840 X 2160.

Most stills cameras will offer you a choice of jpeg compression quality settings, and many offer RAW images too.

In video mode, most cameras will compress heavily - usually into a fairly "lossy" (lots of picture information is discarded) codec optimised for motion pictures and small file sizes.

So a good 4K camera using a high-quality codec in decent light might give you stills you are happy with, and if so that's great for you. (In fact some current compact cams from Panasonic offer exactly that as an option - capture 4K video and scroll through it to choose and save out 8 megapixels stills.)

For many uses, and many photographers, better quality will be a preferred choice. Bigger prints, usually, to look good require plenty of detail - and more is captured in a higher-definition picture.

In video mode, your choice of shutter speed is very constrained, compared to the full range of a stills camera - so if you want long exposures for motion effects or for low light, that can be an issue. Similarly f you want fast shutter speeds to capture moving objects cleanly or to minimize camera shake type blur, that is more or less off the table in your video files too.

Onto compression: big images can contain a lot of data, and to make files usably small compression is almost always used. For stills consumption, jpg compression is standard. Optimised for still images, this offers a range of quality settings -from fairly grotty but very small files to pretty decent for many uses. Many better still cameras will also allow a near-uncompressed RAW image to be captured for later image editing - the route to the best results, in many circumstances.

In video mode. the compression codecs offered are, unsurprisingly, geared to the needs of moving images - so sharpness is not a top priority, and detail loss not apparent when an image flicks by in a fraction of a second is a whole lot more noticeable once you've frame-grabbed your video to produce your still. Of course you can bypass that with really good compression codecs - as on the GH4 - or by sending out uncompressed video to a high quality hard disc recorder. You'd still have the smaller frame sizes and the more restricted choice of shutter speed, though.

http://www.photoshopessentials.com/essentials/jpeg-compression/


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Matt Kelly
Re: Video vs Photgraphy Frame Rate
on May 3, 2016 at 8:56:00 pm

Somewhere in my brain I was familiar with all this information but didn't think to piece it together in that way. Thanks! :)


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