Question about 4K footage in 1080 timeline

200% zoom will give you 1080 because you're basically scaling both horizontal and vertical pixels.

2x1920=3840

2x1080=2160

UHD=3840x2160

Michael Trenton said:

200% zoom will give you 1080 because you're basically scaling both horizontal and vertical pixels.

2x1920=3840

2x1080=2160

UHD=3840x2160

Click to expand...

Thanks.

Michael Trenton said:

200% zoom will give you 1080 because you're basically scaling both horizontal and vertical pixels.

2x1920=3840

2x1080=2160

UHD=3840x2160

Click to expand...

I think you have it backwards, you should be reducing by 2x to make 4K into 1080, so 50% not 200%- 2160/2=1080

TXDego said:

Michael Trenton said:

200% zoom will give you 1080 because you're basically scaling both horizontal and vertical pixels.

2x1920=3840

2x1080=2160

UHD=3840x2160

Click to expand...

I think you have it backwards, you should be reducing by 2x to make 4K into 1080, so 50% not 200%- 2160/2=1080

Click to expand...

I thought he was asking about how far into the 4K footage he could zoom on a 1080 timeline before that footage would end up less than 1080 resolution? But maybe I misunderstood what he was asking?

Michael Trenton said:

TXDego said:

Michael Trenton said:

200% zoom will give you 1080 because you're basically scaling both horizontal and vertical pixels.

2x1920=3840

2x1080=2160

UHD=3840x2160

Click to expand...

I think you have it backwards, you should be reducing by 2x to make 4K into 1080, so 50% not 200%- 2160/2=1080

Click to expand...

I thought he was asking about how far into the 4K footage he could zoom on a 1080 timeline before that footage would end up less than 1080 resolution? But maybe I misunderstood what he was asking?

Click to expand...

Heck we both could be wrong, its simple math either way.

TXDego said:

Heck we both could be wrong, its simple math either way.

Click to expand...

Yes, but you're definitely correct that you'll need to scale 4K footage to 50% in order to view the whole frame in a 1080 timeline. And then basically if you leave the 4K footage at 100% you'll only see half the frame. Zoom to footage to 200% and then your resulting cropped footage should hit the exact resolution of 1080 footage. If you push it any further than that then your cropped footage has less resolution than 1080. Unless my poor math skills are playing tricks on me here.

Gets a little confusing, as some editing apps work in 2x,3x,3x,. and other work in 50%, 100%, 200%,.etc.

But yah, 4k video , has twice the vertical pixels and twice the horizontal pixels,. so the result is 4 times the number of pixels. (and 4 times the file size, generally).

If you drop 4k footage into a 1080 timeline in After Effects (very much like Premiere I believe), it will only show the center 1920x1080 of the 4k footage, so you'd have to scale it down to 50% to show the entire scene (downscaling the 4k to 1080).

So in answering the original question (I guess), never have the 4k footage in a 1080 timeline more than twice the size of the screen to keep things sharp. does that make sense?)

Here's what is confusing everyone. After I dropped the 4K clip into the 1080 timeline, the default is "Scale to Frame Size". The frame will be shown entirely and the Scale in effect is 100%. To enlarge (zoom in), I slide the scale upward (150, 200%, etc.).

But if I disable the Scale to Frame Size on the 4K clip, then the frame will show the entirety at 50% in the Effect Control Scale.

Thanks for the inputs. Now I have a better understanding on this subject.

DMKAlex said:

Here's what is confusing everyone. After I dropped the 4K clip into the 1080 timeline, the default is "Scale to Frame Size". The frame will be shown entirely and the Scale in effect is 100%. To enlarge (zoom in), I slide the scale upward (150, 200%, etc.).

But if I disable the Scale to Frame Size on the 4K clip, then the frame will show the entirety at 50% in the Effect Control Scale.

Thanks for the inputs. Now I have a better understanding on this subject.

Click to expand...

Yes that is because by using 'scale to frame size' you virtually rasterize your footage. So if you plan to zoom in further and/or do some pan and scan then you should use 'set to frame size' or simply drop your footage in the timeline and scale to 50% manually. Otherwise it will negatively affect the quality of your footage when zooming past that 100% mark (Premiere will no longer use the full resolution of your 4K clip when scaling but rather base that scale upon the 1080 'rasterized' version of the footage)