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What is the point of 4k?


zenpmd

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What's the point of anything, really?

What matters is the sensor readout for us... 4K is all the image data. 1080p is traditionally a line-skipped mess or pixel binned atrocity, exception being the A7S.   Go back to 2009, compare 1080p

Geeks calling them DP/film-makers/Cinematographers will tell you that 4k is a big difference with all sort of mathematical formula etc...    But artist and true cinematographers like the ones above wi

Assuming you're rendering to 1080P. You have the ability to reframe and fake things like pans and zooms.

 

But the most important benefit has to do with the image sensor. A Bayer sensor only captures around 1/3 of the detail available. A debayering algorithm is used to interpolate the lost pixels, which causes moire and artificially increases the lost resolution. So you need a 18+ megapixel sensor to output actual 1080 resolution.

 

Simply put: camera sensors usually only capture 1/3 the resolution. So 4K is closer to 1080, but still isn't actually 1080.

 

Simplified even more: sharper detail.

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What matters is the sensor readout for us... 4K is all the image data. 1080p is traditionally a line-skipped mess or pixel binned atrocity, exception being the A7S.

 

Go back to 2009, compare 1080p on the 5D Mark II to a JPEG from the 5D Mark II, now do the same with the NX1 video at 4K and a 28MP JPEG off the same camera and tell me 4K doesn't matter :)

 

We've come a long way, and all in a single year.

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4k is fine and very welcome. De-bayering is still destroying 100% sensor colors even in RAW photos. My GH4 raw photos at 100% looks like perfect 4:2:0 video. Pure colors has less resolution than other parts. Is it then very important to get an external recorder because the RAW sensor data is already noisy and gives unperfect colors?

 

NX1 colors may be much cleaner due to 6.5k to 3.8k sensor downscale.

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other than pulling stills from 4k footage, does  the ability to shoot 4k video change stills in and of itself? i assuem not? sorry i find this a bit confusing.

 

i think i understand the other points made

 

but the outstanding one is - does the resolution matter and can you see it?

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Guest Ebrahim Saadawi

The point of 4K, well, we all know megapixels so it's easier to think of it as still frames. 1080p is 2 megapixels, 4K is 8 mps.

The jump from 1080p to 4K gives you the exact same advantage as jumping from a 2mp camera to an 8mp one.

It's four times the resolution. Four times the information in the picture. If photographers won't print 2mp stills as big as a 50" screen size then why should we accept it? I mean screens are now larger than most photographic prints and we should have high resolution to fill them.

If you ask me, the jump to 8 megapixels in the stills world was the point where I believe digital took over film, because until then film had significantly more resolution. So I think 4K is the point where digital video matches s35 film in terms of resolution, and thing lower is less than HQ film resolution.

1-4K gives you more detail therefore a much sharper image, and sharpness/detail is the most important factor giving the impression of high iage quality to consumers.

2-4K gives you the ability to view or "print" your images on larger screens/projections without looking soft or low quality.

3-4K gives you the ability to make significant framing/cropping adjustments if you're outputting to 1080p video.

4-4K gives you much more room in grading becauss of the higher information, the image keys much better, and you can make percise adjustments/tracks/greenscreen work better than 1080p.

5-4K is high resolution enough to pull still photographs from the video and print them quite large and more than adequate for most professional uses, so it merges professional videography with photography to a great extent.

6-4K in consumer cameras doesn't require the camera to downscale the sensor heavily by using line-skipping or pixel-binning which both reduce quality, so 4K gives us a full pixel-to-pixel read-out, no aliasing/moire and such.

Everything else being equal 4K is just much better than 1080p, no matter your output is 4k or 1080p or even SD. More resolution is better, if you can give me 20k I'd happily take it.

Just make sure you understand it when I say "all things being equal", because there are other factors that can make a 1080p image better than a 4K image on another camera. We're just discussing 4K vs 1080p when everything else is constant.

4K is better and is the future. The only reason you'd choose 1080p is that you can't handle the 4K files in editing, or that you want to deliver 1080p footage straight from the card with no time to downscale in post. Other than that 4K is better.

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This chart seems to suggest its pointless. I assume it doesnt tell the whole story?

 

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Go to a well stocked electronics store and look at the TVs yourself.  If you are satisfied with 720 then just use that.

 

Keep in mind though a lot of what is labeled 1080p is not.  As others are saying because of the bayer sensor you have to record a heck of a lot more than 1080p on a bayer sensor in order to downscale to anything close to 1080p of true detail.  And true detail is not taking mushy Canon 70D video and cranking up sharpening.

 

So if you are satisfied with 1080p off of a blu ray or whatever made from scanned film you will be disappointed with a Canon 70D.

 

Honestly being a logical pragmatic person I bought in to the whole 4K isn't noticeable hype... Then I took my sorry @$$ down to the local electronics store and my jaw dropped.  I also saw downscaled 4K on the internet.  Jaw dropped again.

 

If you are shooting 1080p on an Alexa... okay that is going to look sweet.  If you are shooting "1080p" on a Canon T3i... not so much.

 

True story... I was just at a warehouse store this morning and I heard a house wife say, "My goodness I can see the difference and I'm not even wearing my glasses!"  They weren't shopping for TVs.  They just have the 4k display near the entrance so everyone can see it when they enter.

 

Ironincally they had pallettes of Canon rebels and 70Ds right next to those TVs.  There was also one really low end Sony DSLR on display.  Nothing by Pananonic... as usual.  No Samsung interchangeble lens cameras... no surprise there.

 

So 4k TVs... no 1080p cameras.  Lol!

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I visited a tv store to check that. I was stunned, standing there in front of a 4k screen and watching a demo over and over again.

 

 

True story... I was just at a warehouse store this morning and I heard a house wife say, "My goodness I can see the difference and I'm not even wearing my glasses!"  They weren't shopping for TVs.  They just have the 4k display near the entrance so everyone can see it when they enter.

 

Yeah... I did the same thing. At my local electronics store, there's a 55" Sony HD TV right next to a 55" Sony 4k TV. The image difference is absolutely incredible.

 

Up close.

 

Take a few steps back to what would be normal viewing distance and suddenly the difference is not all that much.

 

Viewing distance and screen size will always play a factor in whether or not it's worth delivering in 4K. The difference on a 55" TV at normal viewing distance is not that huge. But on a 100"+ TV will be very different between HD and 4k. 

 

If you go to a 4K cinema screening and sit up the back, you will be viewing roughly the same detail as if you sit up the front of a normal 2k cinema screening.

 

Something that looks like it's in focus on a 5" screen may be totally out of focus when shown on a 30' cinema screen.

 

When you think that at normal viewing distance on a 55" screen there's not a huge amount of difference, and that there's no mass distribution channel for 4K content, and that television networks have only very recently finished switchovers to HD - and many are still only able to broadcast 1080i because 1080p is too much data, you start to wonder if it's worth buying a 4k television for home viewing within the next few years.

 

However

 

That's not to say that 4K for capture is not worth it. As many above have stated, there are advantages to capturing in 4K, especially if delivering in 1080 HD.

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I'm going to borrow something I posted on DPR.

 

Okay, let's start with normal viewing distances. It's true that there are "optimum viewing distance" recommendations, however this is not how real people's houses work. What normal people do, I've found, is arrange their furniture based on what makes sense physically in their house, then buy a TV that is as large as possible given other constraints (physical and financial). What that distance works out to be depends on your house, but I'd say maybe 8 feet on the low end, 16 on the high end. My comment is primarily with respect to the lower end of that. Call it 8-12 feet. I have no contention with these numbers, though I suspect that most people's screens are not "optimum". Most people are not trying to build home cinemas.

Now there's also a recommendation of what resolution is needed for a certain size screen and viewing distance. Here is a summary of the typical recommendation there:http://www.engadget.com/2006/12/09/1080p-charted-viewing-distance-to-screen-size/

It's these numbers that I disagree with, and it's my contention that these numbers are derived from fundamental misunderstandings of how human vision works. The numbers come from determining that humans can resolve X lines of resolution within 1 arc-second of our visual range, then multiply that number through how many arc-seconds the screen occupies and what the resolution comes out to. This is not at all how human vision works, and furthermore I'll argue that people will consistently prefer a (true) 4K image at 10 feet on a 60"+ screen even if they don't know why. (Note that the chart claims this isn't even close enough to see full 1080p. BS!) The reasoning comes down to metrics of quality that are affected by resolution but not a simple X lines per arc-second. Edge aliasing, contrast, fine pattern rendering, gradation, image noise, etc are all visible very differently in 4K even though they don't follow a simple "resolution of the human eye" formula.

 

That's strictly from the perspective of 4k content display (which is not necessarily the same as 4k content delivery). The arguments in favor of 4k capture are vastly stronger than the ones for delivery or display. We're talking about significant improvements in resolution, color resolution, post processing latitude, etc. Don't forget that the video we're getting off many of these cameras is only theoretically 1080p, but is in fact only resolving 600-900 lines in 4:2:0 color space. That's a lot less data than a true RGB image containing 1080 fully resolved lines.

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Yeah so thats the key.

 

4k Capture - DEFO WORTH OT

 

4k TV - Jury still out. I suspect in the end this will tip me over the edge to finally buy a projector where presumably at its massive size 4k will be great. They are about6k plus right now.

 

That leaves the question, what about monitors for editing? Can you get away with 1080? I see Eizo just released a 31 inch 4k monitor. I have their Color Edge which still costs about £1000. The 4k is going to probably cost 3 times that amount...

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Guest Ebrahim Saadawi

You can definitely edit 4K on a 1080p monitor.

I edit, colour correct and grade 36mp images (8K) on a 1080p display. Works great.

But of course it is better to view the footage and edit them in their native full resolution. That can be achieved by using a separate monitor for vieweing, for example a separate 1080p monitor for vieweing and editing 1080p footage while having the NLE GUI on another. Or by using a 4K monitor and have the 1080p filling quarter the screen and the rest for the GUI. So to edit 4K natively (screen-wise) you'd need an 8K screen or just use a separate 4K monitor all for vieweing.

Editing 4K on a 1080p screen works fine. You don't actually NEED to see each single pixel while cutting or grading.

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Geeks calling them DP/film-makers/Cinematographers will tell you that 4k is a big difference with all sort of mathematical formula etc...    But artist and true cinematographers like the ones above will tell that there is so much more like colour to make a beautiful image. And how 4k is becoming detrimental as too much resolution start to impact the image and how they have to use filtration to soften the image.

 

By the way the bayer filter is more like 2/3 resolution that is why Red Camera the most vocal camera manufacturer about 4k objective was to have 6k for true 4k. But in the end WTF, do people see it? even if it is 2k, 4k or 8k, motion blur and viewing distance will kill 99% of its advantage. You would need to be like 2 feet/50cm from a 65 inch screen to notice any difference and only static scene where motion blur won't take out any advantage in resolution. In this case you would have to move your eyes or head to be able to see all the scene. Its like a ping pong or tennis match if you have two actors talking to each other when they are on two side of the scene.

 

The perception of true 1080p has been ruined by camera like the Canon dslr which even if it is written 1080p are less than 720p in resolution and SD in terms of details with the low 8 bit codec. You should take more the example of the 2.7K down-res Alexa for a proper 1080p image in terms of resolution and detail. Many films like the latest James bond have been shot with the Alexa and up-rez to 4k with no one complaining and DPs (Roger Deakins) have said how it up scaled well.

 

In the end buy Tiffen stocks as when in 2/3 years, when every camera will be 4k and more, everybody on these geeky website will be asking what filter to use to soften the look so that there image look film-like and that the wedding couples, corporate clients, talking heads interviews, film actors to their family members won't be complaining about the highly digital look and crispness of the image.

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