Other: Winner winner, chicken dinner

I meant the 4096x2160 resolution of DCI.

Why can’t we have any resolution we like in any frame aspect we like?


I’m trying to understand the relationship between resolution and aspect ratio. Are all resolutions aspect ratios? If someone says they are shooting “true 4K” they also have to be shooting 17x9? And if someone is shooting “UHD” they have to be in 16x9? There is no such thing as “4x3 UHD”? Why couldn’t a 4x3 image be 8K or, theoretically, 32K?
 
Yes, they are all aspect ratios, which are shapes determined by their width and height.

The resolution formats we deal with are rectangles (and sometimes squares); not circles or triangles or polygons.

This is geometry and it's a standardization, so people can learn together. [Now not all standards are widely-accepted and sometimes there are conflicting ideologies, but not too many people out there are arguing that a rectangle should be called a circle.]

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When something - let's say a square - is 1:1, it's a perfect square. For the sake of simplicity, 1 inch on the left and right sides and 1 inch on the top and bottom.

When you see the frame in your viewfinder, is it a perfect square or does it look more like a rectangle?

If it looks more like a rectangle then that's the reason why there is no 4x3 UHD because UHD also makes up the shape of a rectangle.

Technically, in post, you can fit a UHD rectangle into a 4x3 box and export it as a 4x3 box for various platforms, and generally you can fit shapes into other shapes by cropping and padding, but don't think about that...and view your camera as creating a rectangle that's 16 inches wide by 9 inches tall. Or 17 inches wide by 9 inches tall.
 
JPNola said:
I meant the 4096x2160 resolution of DCI.

Why can’t we have any resolution we like in any frame aspect we like?


I’m trying to understand the relationship between resolution and aspect ratio. Are all resolutions aspect ratios? If someone says they are shooting “true 4K” they also have to be shooting 17x9? And if someone is shooting “UHD” they have to be in 16x9? There is no such thing as “4x3 UHD”? Why couldn’t a 4x3 image be 8K or, theoretically, 32K?
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because every aspect ratio has to be tested. and that time and money they likely don’t care to spend. and at least when going from 17x9 4K to 16x9 4K that is a resolution increase, and who knows what that would lead to at 120fps or 60fps or whatever.


i tend to agree though. Magic lantern sort if changed my ideas of all of that. was wild to see people just go into a dslr and add video features with simple code changes. but allnof that in a corporation involves management, teams, marketing even maybe. and that sounds a lot more expensive to add things to the laundry list, especially after the fact.


and red obviously goes mad with their cropping and ratios. great to have, even if it drives some people mad. but Red does not seem to give an F about testing that thing, and they likely just throw it in there regardless, and see if anything happens in the wash. Arri and Sony might actually test it, or at least not put it in if they haven’t tested it.
 
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i do prefer seeing 17x9 in 4k and 16x9 in UHD, since those are picel accurate.

but it would be nice to have a 16x9 “open gate” and you have the option to crop for DCI or downres for UHD, and not really lise information.

i absolutely hate the idea of shooting UHD in letterbox to get 17x9. haha. but hey, we gotta do what we goota do sometimes, i guess.
 
All of these numbers are virtually arbitrary. If UHD was 4096 across and DCI was cropped from that and both versions were presented side by side, it's incredibly unlikely anyone would detect the difference of like 100 pixels out of 4000, even projected in a theatre. Netflix calls 3840 UHD "true 4k"...why sweat it?!
 
Im shooting with my C200 raw now which is 17:9 Most of my deliverables will be 16:9 so while I dont need to sweat it I do need to give some consideration to allowing a 'safe area' when tight framing. I'm sure there are bars in the menu, but the menu is not a place real men go.
 
Doug Jensen said:
Absolutely. UHD is 4K.

This discussion boils down to two concepts: 1) Resolution and 2) Aspect Ratio.
One has nothing whatsoever to do with the other.
Why is that so difficult to understand?
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Serious question .. how is UHD (Ultra HD) 4K .. its neither 4K in pixels or resolution .. the only "true 4K" would be like the fx9, down sampling in camera from a 6K sensor, to achieve over 4K resolution after debayer .. 4K pixel sensor is not 4K resolution after debayer .. ?
 
That's just going to add more to the confusion, but those are two different things.

Anything on paper providing close to 4,000 pixels (W) is 4K. You can call it whatever you want (there are more names for it than just UHD/DCI 4K), but the world has standardized it to be accepted as a 4K resolution product.

Then what you're talking about is the process that creates resolution and improves on it and its signal-to-noise ratio (& other characteristics), and it is a conversation from an engineering point of view and how much native resolution you need to begin with in order to create a higher resolving image with increased color information.

So yeah..."true 4K" might not be really 4K to a camera forum geek, but it's 4K as a product sold in stores.
 
Donny 123 said:
Serious question .. how is UHD (Ultra HD) 4K .. its neither 4K in pixels or resolution .. the only "true 4K" would be like the fx9, down sampling in camera from a 6K sensor, to achieve over 4K resolution after debayer .. 4K pixel sensor is not 4K resolution after debayer .. ?
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4K is a marketing term. Any video signal with a resolution of 3840x2160 or 4096x2160 can legitimately be called "4K" regardless of how that resolution was created. When more specificity is required, then "DCI" or "UHD" can be tacked on to identify the type of 4K, but both of them are 4K. Now if you happen to think the quality of a 3840x2160 or 4096x2160 image that is derived from debayering doesn't provide acceptable quality for your standards, that is a whole different topic for another debate. But the signal is still 4K. Even if the video is B&W with no color at all it is still 4K if the resolution is 3840x2160 or 4096x2160.
 
Doug Jensen said:
4K is a marketing term. Any video signal with a resolution of 3840x2160 or 4096x2160 can legitimately be called "4K" regardless of how that resolution was created. When more specificity is required, then "DCI" or "UHD" can be tacked on to identify the type of 4K, but both of them are 4K. Now if you happen to think the quality of a 3840x2160 or 4096x2160 image that is derived from debayering doesn't provide acceptable quality for your standards, that is a whole different topic for another debate. But the signal is still 4K. Even if the video is B&W with no color at all it is still 4K if the resolution is 3840x2160 or 4096x2160.
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Yeah marketing is the thing here ! "as sold is stores " .. but just logically how is 3840 4K pixels ,let alone resolution ..empirically its not 4K pixels ,and after debayer its no where near it .. Its a wonder that professionally this 4K marketing of TV,s and handycams has caught on ..
 
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Logically it is 4K because it's close enough and who in the world is going to see with their human eyes that an image is missing 256 pixels.

Technically it wouldn't be if some sort of organization is asking for 4096 but you're providing 3840.

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This philosophical thinking also applies to the HD cameras we've used in our lives...most of those were closer to 720p but were called HD cameras when they were providing 1080p (but really weren't).
 
Doug Jensen said:
Absolutely. UHD is 4K.

This discussion boils down to two concepts: 1) Resolution and 2) Aspect Ratio.
One has nothing whatsoever to do with the other.
Why is that so difficult to understand?
Click to expand...

Got it. The resolution “3840x2160” has nothing to do with aspect ratio. Because “Resolution and aspect ratio have nothing whatsoever to do with each other.”

Then why are “ 3840x2160 ” and “ 4096x2160” referred to as aspect ratios?

Plotted out, are both not geometric shapes, whatever unit one uses, be it inches, feet, pixels, or floor tiles? Are they not geometric shapes as are “”16x9” and “4x3”?


“ Why is that so difficult to understand?”

Because my strength is not video engineering but shooting and lighting.
 
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NorBro said:
Logically it is 4K because it's close enough and who in the world is going to see with their human eyes that an image is missing 256 pixels.

Technically it wouldn't be if some sort of organization is asking for 4096 but you're providing 3840.

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This philosophical thinking also applies to the HD cameras we've used in our lives...most of those were closer to 720p but were called HD cameras when they were providing 1080p (but really weren't).
Click to expand...

720 is HD. Just as 1080 is HD. “Full HD” is a marketing term that the consumer TV manufacturers coined many years into the HD rollout to get consumers to throw out their couple-of-year old HD sets that they had spent thousands of dollars on to buy new HD sets for thousands of dollars, again. That didn’t surprise me. What did though, was how quickly that term came to be used on the professional side. Even though in the ATSC specs, there was never any distinction(besides the resolution itself) made between 720 and 1080. They were both just labeled HD.

It’s almost as bad as the marketing for 4K. In HD(16x9), everything was referred to by the vertical resolution(720 & 1080). The LOGICAL progression for UHD would have been to say 2160, because that’s the vertical resolution. BUT, that doesn’t sound like that much of a difference from 1080, so they had to come up with something that sounded bigger and better, like the horizontal resolution, since there are more pixels across than vertically in 16x9/17x9 aspect ratios. Well, the DCI version of HD was 2K, because the horizontal rez was 2048, which is just a 17x9 version of 1080 HD(16x9). And the DCI version of UHD is 4096x2160(4K), so they just decided to refer to both formats as 4K. That’s something they could market to consumers easier. I’m sure if you ask the average consumer that’s not on a home theater message board what 2K is, they won’t have a clue. But they’ll by-God know what 4K is, even if they don’t really know.
 
What I meant above is that the HD cameras (regardless if they were 720p or 1080p) were sold as HD cameras, and barely any had high resolutions sensors in them and definitely no modern oversampling yet no one questioned their resolution.

The resolution overall was so awful that who knows what they actually resolved yet no one questioned if they were true 720p or full HD cameras because cameras weren't marketed like that.

But today it is a feature. When questions are asked about AF or IBIS or 10-bit or RAW, some of those people are going to ask how's the camera's 4K being made.

No one on the planet knew to ask stuff like that 10 years ago besides the 1%.
 
In short, no matter what the rest of the world does with shapes and resolutions, camera operators have to view them as rectangles and squares based on resolutions because that is what cameras create. As far as what you could make it look like later in post-production is another topic.

P.S. This is worth a look: https://www.red.com/red-101/video-aspect-ratios
 
NorBro said:
Logically it is 4K because it's close enough and who in the world is going to see with their human eyes that an image is missing 256 pixels.

Technically it wouldn't be if some sort of organization is asking for 4096 but you're providing 3840.

___

This philosophical thinking also applies to the HD cameras we've used in our lives...most of those were closer to 720p but were called HD cameras when they were providing 1080p (but really weren't).
Click to expand...

I hope air traffic control and surgery never adopt this logic .. :)
 
ha...highly inaccurate comparison, really makes me think you're not really sure what resolution is.
 
'close enough to the correct number' has been the MO for storage manufacturers to list their new drive's capacity for decades.
 
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