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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Lens conversion 4k->3k->2K

With a 100mm lens the FOV you experience should be something like this:
4k 100mm
3k 150mm
2k 200mm
 
In relationship to 35mm still photography and doing my math for horizontal coverage, the more useful measurement IMHO, and with Deanan's data of sensor size (4K 16:9 RED = 22.12mm x 12.44mm):

35mm still: 36 x 24mm, 1.0x
RED 4K: 22.12 x 12.44mm, 1.63x
RED 3K: 16.59 x 9.33mm, 2.17x
RED 2K: 11.06 x 6.22mm, 3.25x

100mm in 4K is like 163mm, in 3K like 217mm and in 2K like 325mm.


In relationship to 35mm film format with the RED sensor in 4K as basis:
RED 4K: 22.12 x 12.44mm, 1.0x
RED 3K: 16.59 x 9.33mm, 1.33x
RED 2K: 11.06 x 6.22mm, 2.0x

100mm in 4K is 100mm, in 3K like 133mm and in 2K like 200mm.


I hope this helps and doesn't cause confusion.
 
Thanks Hamlet. If you want to do direct calculations, you can use 5.4u for the pixel size.
 
Towards the wide angle side

Towards the wide angle side

Hi colleagues

Thanks for this kind of calculations! IMO shooting 2k with 35 mm lenses results in a problem in the wide angle world.
That's the reason I have still some hope for 2k scaled, even if it looks like the RED team doesn't like the idea...

Best regards,

Roland, Switzerland
 
Hmmmm.

I was under the impression that the 2K setting was scaled, not cropped. I guess for any of my work I will have to shoot in 4K and res-down in post just like I do with my still cameras. Why limit yourself while shooting?

Steve

blr said:
Hi colleagues

Thanks for this kind of calculations! IMO shooting 2k with 35 mm lenses results in a problem in the wide angle world.
That's the reason I have still some hope for 2k scaled, even if it looks like the RED team doesn't like the idea...

Best regards,

Roland, Switzerland
Click to expand...
 
4 k versus 2 k

4 k versus 2 k

Why limiting to 2 k while shooting? Well this question seems to split the RED community. While the cineasts prefer to go the 4 k way, others (like me) are working for the broadcast world too. And there it's a question of resources and time. Downres in post is very time consuming, even Apple's actual 8 core number crackers seem to need hours up to days (depending on the amount of footage you have) to do this job. Furthermore it's a question of resources concerning your memory card. In 4 k you have to exchange cards after a few minutes. Of course, you can use the HD instead of the cards. However, in case you will end in Apple's Prores HQ as 1920 x 1080, 4 k doesn't make that much sense. But I know: There are a lot of colleagues who do not agree with my point of view...

Regards, Roland
 
Real-world numbers, based on using a zoom lens. Ballparked because there's no absolute readout for 30mm on this lens.

2K @ 20mm = 3K @ 30mm = 4K @ 40mm.
 
Hope this has not been asked too often:

My end media is 1080p. Shooting in 4K, I have switched to 2k a couple of times because of a missing telephoto lens. Now I´m wondering if that was a good move.
I could have cropped the (too wide) 4K shot instead and would have had the ability to reframe / stabilise / pan.

Only disadvantage is an additional 2K render to QT (instead of using the 2K proxies).

Right?

Jochen
 
For the idea of getting longer shots, indeed you could have cropped in post.
Result is the same and you have reserve for stabilizing.

If you intend to use the higher framerates, you'd be stuck to the cropped area though.
 
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