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Old September 15th, 2013, 04:58 AM   #1
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Why 2.5K?

I have seen the advantage of 4K as there are now affordable 4K TV's and the price will come down with time.

But what is the advantage of 2.5K? I don't see any 2.5K TV's on the market.
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Old September 15th, 2013, 05:45 AM   #2
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Re: Why 2.5K?

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Originally Posted by Bob Prichard View Post
I have seen the advantage of 4K as there are now affordable 4K TV's and the price will come down with time.

But what is the advantage of 2.5K? I don't see any 2.5K TV's on the market.
There are probably plenty of benefits, but the main reason I shoot 2.5k on my GoPro is the ability to crop/zoom in my NLE without noticeable quality loss.

If my maths is correct (which it probably isn't, but you get the idea), you could zoom in by 50% and still have a 1280x720 frame, suitable for web upload.

It gives you the ability to mimic camera zooms/pans when there isn't any.
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Old September 15th, 2013, 07:06 AM   #3
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Re: Why 2.5K?

Jody's right.

You can also mimic slider shots from a 1080p frame.
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Old September 15th, 2013, 10:42 AM   #4
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Re: Why 2.5K?

Any other benefits to shooting 2K or 2.5K besides cropping and sliding?
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Old September 15th, 2013, 03:39 PM   #5
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Re: Why 2.5K?

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But what is the advantage of 2.5K? I don't see any 2.5K TV's on the market.
There are a few advantages. Depends on the target camera's firmware algorithms. But one thing you can get from a 2.5k single sensor camera (that is 1mos, not 3mos) is oversampling of a 1920 x 1080 result, which improves effective resolution of the 1920 x 1080 output, improves noise characteristics, MTF, etc. In fact, most cameras do this, they just don't show it to you. IOW, many cameras are internally 2.2k, but they only show you the 1080 result.

What you get when you take a beyer sensor and add an anti-aliasing filter, is a sensor that can give you around 70% of your 1080 resolution once it's been de-beyered. So your 1080 source file can only resolve around 750 lines of actual image information.

To make customers happier, manufacturers try to get 900-1000 lines of resolution from their single sensor 1080 cameras. The easiest way to do this is to increase the internal resolution to, you guessed it, 2.2k+. Most of them just don't expose that 2.2k+ resolution to you.
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Old September 15th, 2013, 03:51 PM   #6
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Re: Why 2.5K?

Bruce,

Thank you for your helpful reply.

The reason I am asking this question is that I am thinking about getting the Odyssey 7Q for my Sony FS700. I shoot mostly landscape videos and want to get the best resolution, color and dynamic range that I can. I was hoping that the 7Q could record 4K, but Sony has not granted them a license.

Is the usual method in post to edit in 2K and then downrez to 1080P? Or do you downrez first and then edit in 108-P?

Can you see the difference on a 55" or larger screen?
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Old September 15th, 2013, 06:35 PM   #7
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Re: Why 2.5K?

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The reason I am asking this question is that I am thinking about getting the Odyssey 7Q for my Sony FS700. I shoot mostly landscape videos and want to get the best resolution, color and dynamic range that I can. I was hoping that the 7Q could record 4K, but Sony has not granted them a license.
The 7Q does record 4k from the FS700.
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Old September 19th, 2013, 10:44 AM   #8
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Re: Why 2.5K?

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Originally Posted by Bob Prichard View Post

The reason I am asking this question is that I am thinking about getting the Odyssey 7Q for my Sony FS700. I shoot mostly landscape videos and want to get the best resolution, color and dynamic range that I can. I was hoping that the 7Q could record 4K, but Sony has not granted them a license.
...Can you see the difference on a 55" or larger screen?
Bob - Gary is correct. What Dan Keaton actually said was Sony has not granted CD a licence to record 4K RAW - the 7Q will record 4K 10 bit compressed. At up to 60fps. Your only choice if you want 4K raw from this camera is to go down the very expensive and heavy Sony route.

The size of the screen has nothing to do with the resolution - a 1080P screen is still a 1080P screen.

It really comes down to whether your source resolution is really 1080P or not... some cameras cannot resolve the full 1080 lines.

The other advantage to the upgrade which you should consider carefully as a landscape videographer is that 2.5K raw gives you an enormous amount of latitude. You get a bump in latitude just by doing the version 3.0 upgrade with Sony because that gives you access to S LOG2. I'm pretty sure you can record that to the internal cards, but recording externally to RAW will give you maybe 6 more stops..read Adam Wilts and Art Adams articles on this forum.

Remember more latitude less blown highlights and more shadow detail. But usually much more correction in post using something like Davinci Resolve.
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Old September 19th, 2013, 11:35 AM   #9
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Re: Why 2.5K?

John,

Thanks for clearing things up for me.

Do you edit in 2.5K or 2K and then down rez to 1080P for distribution and display?
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Old September 19th, 2013, 09:29 PM   #10
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Re: Why 2.5K?

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John,

Thanks for clearing things up for me.

Do you edit in 2.5K or 2K and then down rez to 1080P for distribution and display?
Nope - my FS700 seems to have plenty of resolution to me @1080P for normal work provided I'm using a good quality lens. As I said - the bigger consideration for you would be latitude and also whether you want to shoot in 4K eventually for those displays.

I do a fair bit of green screen work so the 2.5K raw or even 10bit compressed would give me a lot more color resolution than the current setup. That would be my main reason for getting something like a 7Q..
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