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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 :)

Why 4k

Is there a benefit in terms of controlling depth of field with 4k over 2k? Can I get a shallower DOF with 4k? If so, how substantial is the difference.
 
Boothba said:
Greame: I think I once heard you say that REDCODE is only for footage coming out of the camera. But it strikes me that REDCODE would be a fabulous archiving format. At the moment I plan to convert all RED 4K REDCODE footage to tiff image sequences (uncompressed) for post processing, grading, vfx, etc. Is there a way that we can re-compress these final shots to REDCODE (on redcine?) at the end of the day before archiving?

Thanks
Click to expand...

Wow! Uncompressed TIFF's are hardcore! RLE, zip, rar, and tape hardware compression do a nice job of reducing the size of TIFF's and are more of an IT industry standard.

No need for REDCODE.

M
 
Graeme Nattress said:
I don't see 4k as being 4 times the work though,

4k rotoing isn't going to be slower. Roto work is a human tracing an edge with vector tools. Image resolution doesn't make this process take longer, and the cleaner the edges to see, the better, I'd think, not worse.

CG work is going to take longer to render. That's true, but it's not the end of the world as render power is growing much faster than image raster size :-)

That said, I see the biggest 4k slowdowns are the things you do every shot - colour correction, and that's where a good GPU can really help, and that technology is with us today.

Graeme
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Hi Graeme... this is an excellent conversation and I'm enjoying the dialog. I fully intend to monopolize a few minutes of your time at NAB and a bit longer block when I come out to Cali to pick up my RED in person. :)

First, I haven't seen but two displays of single projector 4K... the CineAlta Festival two NAB's ago when the Sony projector was just cutting its teeth (showing all 1080 material if I remember) and last NAB where I saw the Mystic India footage that was from 65mm. I haven't had the chance to see RED footage yet... I hope the upcoming NAB takes care of that!

My guess is that a larger than 4K sensor will be needed to pack a 4K final projection frame as well as the current 4K RED design will pack a 2K projection frame. But God Bless the RED for starting out with all those pixels.

But on to the CGI aspect of this thread... Thomas has excellent points, and I want to add my work experience into this.

First, 4K roto will be much more difficult because the artist precision needed is that much higher. Hair that's a simple blur in SD or HD resolves into individual strands at 4K. I've had personal experience on feature films doing roto (sadly) and you can get away with murder at SD compared to HD or 2K.

Second, CGI 4K effort won't be a simple factor of render power applied. God I wish it was. Let me address some problems I ran into on a 4K by 4K job, completely ignoring all issues related to computer power or memory requirements...

1.) Texture maps. Even for SD work, 2K texture maps are often used. In doing FX at 2K I've often had to paint or stitch up images at 10K or greater. To make 4K look GOOD you need MUCH larger imaging ability... beyond what you can easily get in one snap of the best DSLR today. Again, labor and time. The resolution required for an environment pano for a 4K scene using a CGI camera of moderate focal length boggles the mind. At least my feeble mind.

2.) Model quality. Doing a quality CGI model that will hold its close-up in 4K becomes that much harder and takes more man hours. Again, this is application of human labor.

3.) Aliasing control. In CGI you often have to render at a size bigger than your final to keep certain things from aliasing (fine lines, regular patterns). How big will you have to go to "fix" these issues if your nominal size is 4K? Big, bigger...

These are a couple reasons on top of all the other factors previously mentioned that keep 4K FX from being commonplace. You haven't seen a high shot count movie be all 4K for very good reason.

Of course all this will change in time, and at a fairly fast pace, I imagine. But now, TODAY, I'm very pragmatic and realistic when thinking about projects, and a 2K finish starting from the 4K RED "negative" makes the most sense for the kind of work I'm interested in.

On the flip-side, I'd gladly post a "bunch of people in a diner talking" with minimal fx sort of movie at 4K however... :)
 
I think Spiderman 2 was all 4K.

But I agree. The more post work you do, the more it makes sense (currently) to shoot 4K and finish in 2K or HD. Or maybe I'm just a wimp.
 
Graeme Nattress said:
I don't see 4k as being 4 times the work though,

4k rotoing isn't going to be slower. Roto work is a human tracing an edge with vector tools. Image resolution doesn't make this process take longer, and the cleaner the edges to see, the better, I'd think, not worse.

CG work is going to take longer to render. That's true, but it's not the end of the world as render power is growing much faster than image raster size :-)

That said, I see the biggest 4k slowdowns are the things you do every shot - colour correction, and that's where a good GPU can really help, and that technology is with us today.

Graeme
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I disagree with 4k roto not being slower. OF all the roto work I have done in the past, it was easier get through it in SD than 2k. I would have more resolution to find finer edges, but overall it took longer.

When CG renders take 24 hours per frame at 2k from what I have been told at Siggraph presentations, I see it being even more complicated when you have to render out at 4k.

It's not just a matter of switching out a quad core machine with an 8 or 16 core machine either. A lot of it is knowing how to manage and streamline your rendering.
 
Boothba said:
I think Spiderman 2 was all 4K.

But I agree. The more post work you do, the more it makes sense (currently) to shoot 4K and finish in 2K or HD. Or maybe I'm just a wimp.
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Spiderman 2 was a 4k DI, but all the visual effects work was done in 2k.


With Flame/Inferno, you can use proxies to do your roto, paint and comp work in a lower resolution, then it would automatically apply those results to the higher resolution source.

That should be how we should have it in the future, doesn't matter what your source is, allow you to work in proxy mode, and then allow you to render at whatever resolution you decide, yet you have the project files to go back to later when you want to rerender at a higher resolution.
 
Brook Willard said:
No, it's 300% more. ;)
Click to expand...
?

Well,

[@16:9 ratio]
2048 x 1152 = 2 359 296 [2K]
4096 x 2304 = 9 437 184 [4K]

it gives 400% more...or am I wrong or are you joking with me, Brook? ;)
 
Render times can be > 4x because of ram limitations and how you break up the BSP trees. It'll also require everything to be detailed better, not just rendered at a higher resolution, that means more time.

I agree with Roto taking longer as well. with DV you can get away with a lot of cheating, not so with 4k. If you actually need to 'roto' 'roto' and not just key the hair, you have more hair you have to roto in 4k.
 
CGI rendering is very parallelizable though. For texture complexity, hybrid texture + procedural shader will give all the detail you'll ever need :-)

If you're going to to bother of rotoing every hair visible in a 4k shot, methinks you've got other problems.... Perhaps that shot is better done all CGI, or... ?

Graeme
 
Graeme Nattress said:
CGI rendering is very parallelizable though. For texture complexity, hybrid texture + procedural shader will give all the detail you'll ever need :-)

If you're going to to bother of rotoing every hair visible in a 4k shot, methinks you've got other problems.... Perhaps that shot is better done all CGI, or... ?

Graeme
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The realities of production is that not everything is thought out or expected to be an effects shot.

I once had to roto, in 2k, a man swinging his body around wildly, of course he had long hair. It wasn't meant to be an fx shot, but the production decided to digitally change the background.
 
Dratted people who decide to change backgrounds :-) I don't envy you on that one!

Graeme
 
I found this quote amusing from one of the colorspace guys regarding 4k:
http://www.dvxuser.com/V6/showpost.php?p=557920&postcount=34

"As far as 4k versus 2k, I really don't want to turn this into a long rant, but if you know even a single person who is working 4k, I would be very suprised. If fact, i'd be [a bit] suprised if you knew someone who even was working with 4k images from a D-SLR, since there are maybe 8 D-SLRs that support this resolution... and D-SLRs are meant to approximate more than double the resolution of 35mm motion picture film.

The fact of the matter is that 4k is an exorbitantly expensive workflow to support; and packing that type of resolution into a 35mm chip degrades the type of performance you can see in other areas. We considered 4k, but 2k is the current standard for the industry, and that's why we chose 2k-- it ended up being the "sweet spot" with regard to the total performance of our chip. I'm not saying 4k isn't great, or that the industry won't eventually shift there, but that isn't the current standard, and going 4k would have required us to make sacrifices in other areas. "

A quote from David Stump regarding 4k back in November:
http://www.assimilateinc.com/pdfs/Q&A-DavidStump.pdf

What do you like about 4k?
One word: clarity. It harkens back to the beauty you saw achieved in the first print from 65mm or Vista Vision - strikingly crisp and clear.
I expect the clarity and resolution of the Red 4k camera to be just as good. The results are so striking that studios will now be willing to take the risks to achieve more resolution, more color space.
 
Thanks for that Tonaci - most amusing. I don't think anyone who's seen what 4k can do would want anything less :-)

Graeme
 
bump.....
How does 4K impact DOF and how does it compare with 2K?
 
Well, technically, it doesn't. Only thing that affects DOF is aperture. However, larger sensors make longer lenses look shorter, and longer lenses magnify the image making blurred background appear more blurred, hence make DOF look shallower. So, simple answer is 4k looks shallower, but technically nit picking answer is that it doesn't change a thing.

Graeme
 
Graeme Nattress said:
Well, technically, it doesn't. Only thing that affects DOF is aperture. However, larger sensors make longer lenses look shorter, and longer lenses magnify the image making blurred background appear more blurred, hence make DOF look shallower. So, simple answer is 4k looks shallower, but technically nit picking answer is that it doesn't change a thing.

Graeme
Click to expand...

Well, isn't DOF dependent of the Circle of Confusion used? A 4Kprojection has a different CoC of a 2K projection. So Wouldn't it have some consequences on DOF?

(For instance, 35mm motion picture has different DOF when it's projected in a theather or when it goes to SD television. Technically, the DOF is the same, but since there aredifferent tolerances for the different viewing methods, DOF does change...)
 
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