Which is better for green screen, GH5 10 bit 4K, or BMPCC RAW?

[Rank Amateur]

Lighting and green screen materials aside, I'm trying to determine which camera would lend itself to an easier, cleaner key as between the GH5 10 bit 4K and the BMPCC RAW? I believe the GH5 10 bit 4K is 4:2:2. Is the BMPCC RAW equivalent to 4:4:4? If BMPCC RAW has the edge, is it enough of an edge to warrant dealing with the BMPCC's lack of... seemingly just about everything except codec relative to the GH5? Thanks in advance for your thoughts!

[deezid]

The GH5 would be, since it's oversampling from 5k, but the processing limits its performance.
The best you can probably get is the FS5 with external RAW, it's flawless.

[Jonesy Jones]

GH5

I spent all of last summer shooting green screen with the GH4 and it keys wonderfully. I also tested with the BMPCC and was just so so. The BMPC 4K keys amazing, but in our case the difference between that and GH4 was nominal and didn't justify the increased data rates. I haven't tested it yet, but if the GH5 keys any better than the GH4, which it should, then it should be pretty close to flawless. 

[HockeyFan12]

I haven't used either (at least not extensively) but RAW isn't 4:X:X in the traditional sense of the term. 4:X:X defines the color resolution of the recording codec following internal RAW conversion, whereas RAW has yet to be converted into anything. The GH5 should have more color information to start with due to its greater pixel density and I find 4:2:2 more than good enough for keying anyway. Haven't noticed any real difference between 444XQ and 422HQ for keying tbh. Maybe in really challenging scenes? I generally denoise everything before keying anyway and that recovers some lost color resolution from the temporal denoising and smooths everything out. It makes sense that the GH5 would key better but I would definitely try both before buying either. 

[jcs]

GH5 in a heartbeat!

[Rank Amateur]

8 hours ago, deezid said:

The GH5 would be, since it's oversampling from 5k, but the processing limits its performance.
The best you can probably get is the FS5 with external RAW, it's flawless.

Thanks for your replies, everyone. I'm surprised to hear the consensus appears to be that the GH5 would key better. I finished my green screen studio yesterday and did some tests with BMPCC RAW. The results had me reconsidering my plan to sell my BMPCC setup in favor of the GH5, but your comments suggest that I was on the right track after all.

deezid, do you mean to say that the GH5 would be better, but isn't because its performance is limited by its processing? Or do you also feel it is better for green screen work than BMPCC RAW?

7 hours ago, Jonesy Jones said:

GH5

I spent all of last summer shooting green screen with the GH4 and it keys wonderfully. I also tested with the BMPCC and was just so so. The BMPC 4K keys amazing, but in our case the difference between that and GH4 was nominal and didn't justify the increased data rates. I haven't tested it yet, but if the GH5 keys any better than the GH4, which it should, then it should be pretty close to flawless. 

Do you recall what your BMPCC setup was, Jonesy Jones?

6 hours ago, HockeyFan12 said:

I haven't used either (at least not extensively) but RAW isn't 4:X:X in the traditional sense of the term. 4:X:X defines the color resolution of the recording codec following internal RAW conversion, whereas RAW has yet to be converted into anything. The GH5 should have more color information to start with due to its greater pixel density and I find 4:2:2 more than good enough for keying anyway. Haven't noticed any real difference between 444XQ and 422HQ for keying tbh. Maybe in really challenging scenes? I generally denoise everything before keying anyway and that recovers some lost color resolution from the temporal denoising and smooths everything out. It makes sense that the GH5 would key better but I would definitely try both before buying either. 

What do you use to denoise your footage before keying, HockeyFan12? Does that help stop the "dancing noise" I often see after keying? Can it be as simple as adding Keylight or zMatte beneath a denoise filter in After Effects, or do you render out a denoised clip and key that instead of the original?

I have a few additional related questions:

GH5 Update

1) Do you guys think the forthcoming 400 Mbps ALL-I update for the GH5 will make the GH5 even better for keying than it is now?

Lens

2) I painted a 12' wall and a perpendicular 9' wall in my basement with Rosco DigiCompHD paint and put down Rosco chroma floor (what a great find that was, it sure beats slipping on the muslin cloth I'd tried to weigh down at the corners). I wanted some depth to my green screen area so that I could shoot "talent" moving around, do and track camera moves and composite 3D objects, backgrounds, etc. However, because there is very little room for me to move back from the green screen area to shoot, my BMPCC + Metabones BMPCC Speed Booster (.58x crop) + Sigma 18-35 lens can't get the talent in the frame from head to toe when they step more than a few feet away from the wall. For that reason, I'm considering swapping out the Sigma 18-35 lens for something with a wider field of view.

Which of these lenses do you think would be the sharpest with the least amount of barrel distortion (important for camera tracking)?

Irix 11m f4 - https://www.bhphotovideo.com/c/product/1325647-REG/irix_il_11bs_ef_11mm_blackstone_lens_for.html

Venus Optics Laowa 12mm f2.8 - https://www.bhphotovideo.com/c/product/1283911-REG/venus_optics_ve1228cef_laowa_12mm_f_2_8_zero_d.html

Also, since my BMPCC Speed Booster wouldn't work with the GH5, which Speed Booster and mount type (Nikon, Canon) would you suggest?

Alternatively, without a speed booster

Laowa 7.5mm f/2 MFT - https://www.bhphotovideo.com/c/product/1337244-REG/venus_optics_ve7520mftstblk_laowa_7_5mm_f_2_mft.html

Panasonic 12-35 f2.8 II - https://www.bhphotovideo.com/c/product/1304868-REG/panasonic_h_hsa12035_lumix_g_x_vario.html ? I had planned to get this lens since I believe I read it provided the best autofocus and stabilization for the GH5, but I'm afraid it wouldn't be wide enough.

Tracking Markers

3) What do you suggest for tracking markers? It took me a long time to prime and paint my basement walls, and the green screen paint was expensive. I'm very paranoid about getting them dirty or scuffed up as a result. However, I need tracking markers on the walls or else I'll only ever be able to do static shots (since I wouldn't be able to make the background move with the camera without them). Can you suggest anything that would work well as a tracking marker that I could leave on the wall indefinitely and won't damage/leave residue/chip/etc. the paint?

Thanks for your help and advice!

[Jonesy Jones]

5 hours ago, Rank Amateur said:

Do you recall what your BMPCC setup was, Jonesy Jones?

Yes, BMPCC + Sigma 18-35 + speed booster. I shot Prores HQ.

Here are my lessons learned from all green screen shooting I did. This is in order of importance, the higher up the list, the more impact it had on getting a better key.

1. Resolution is more important than bits. I would pretty much choose 4K over any 2K camera for keying, if the key is the most important factor. This goes against much of what I heard around the interweb, but I found it to be true. Think about it, maybe this is why Red is such a popular choice among filmmakers who do tons of green screen - Peter Jackson, David Fincher, etc.
2. DON'T stick to the 180 degree shutter angle or double your FPS for shutter speed rules. Increase your shutter speed (or lower your shutter angle) to reduce motion blur, which won't key well. On the GH4, I shot at 24P (some use 30 for keys but I didn't notice a difference in key and didn't like the result) with a shutter speed of like 80 or 90. Nearly or no motion blur artifacts.
3. Bits do make a difference.... but resolution matters more. With 4K and 10+ bits you'll get perfect keys, with crazy fine detail. Possibly consider the BMPC 4K.
4. DON'T overexpose your green screen. As you increase exposure you will begin to decrease saturation which will inhibit keying in post. 
5. Use false color to expose your green walls to get it even. To be honest, that corner you've created with the 2 perpendicular walls is going to pose a pretty serious problem. That corner will be very difficult to light properly. If at all possible, build a short sweep to make that corner a curve. 
6. If you do get dancing noise in darker portions of the image, try a 3-way color corrector (only found in Lumetri if in After Effects) and gently nudge the darks away from green toward magenta. Didn't really affect the image and massively cleaned up noise for me.
7. I found HSL to be a tremendous despill tool. And for me, most of the green around the subject was actually in the yellow channel. So, go to the yellow channel and begin sliding the Hue toward red, and reduce saturation a touch. Worked beautifully.

This may or may not apply to you, but since I only had 1 subject, I mounted my camera at a 90 degree angle (so portrait mode) and gained a ton more resolution in doing so. But if you have more than 1 subject this may not work. 

Most people use painters masking tape for the tracking markers, the thinner not the wider. 

We have no idea what the 400 mb/s upgrade will do for the image until we see it. In theory, this update will give us something close to Prores LT, which are both around 50 MB/s. I'm looking forward to it for my GH5. 

EDIT: before I tried any of the above, I worked really hard on exposing the screen properly. Once I got it exposed pretty good, then the above list produced the results in that order. However, if you do a really sloppy and poor job of lighting your screen, probably nothing above will help. 

[HockeyFan12]

8 hours ago, Rank Amateur said:

What do you use to denoise your footage before keying, HockeyFan12? Does that help stop the "dancing noise" I often see after keying? Can it be as simple as adding Keylight or zMatte beneath a denoise filter in After Effects, or do you render out a denoised clip and key that instead of the original?

The industry standard is Neat Video, which is $99. It will get rid of that noise, but it will also reduce the texture of the clip in a way you might find objectionable. In that case, just use the keyed layer as a track matte for another layer with only a spill killer on it and no noise reduction. Or regrain.

[hmcindie]

8 hours ago, Jonesy Jones said:

Here are my lessons learned from all green screen shooting I did. This is in order of importance, the higher up the list, the more impact it had on getting a better key.

1. Resolution is more important than bits. I would pretty much choose 4K over any 2K camera for keying, if the key is the most important factor. This goes against much of what I heard around the interweb, but I found it to be true. Think about it, maybe this is why Red is such a popular choice among filmmakers who do tons of green screen - Peter Jackson, David Fincher, etc.

Alexa keys better than Red 5k. Less noise in color channels.

[HockeyFan12]

36 minutes ago, hmcindie said:

Alexa keys better than Red 5k. Less noise in color channels.

I've found this to be the case, too. The Alexa's noise also responds better to noise reduction and there's more separation between the green and red chromasticities. That said, Red footage seems to key fairly well, too.

[Jonesy Jones]

6 hours ago, hmcindie said:

Alexa keys better than Red 5k. Less noise in color channels.

I've never keyed either. So I guess I'll take your word for it. But there must be some reason most tentpoles choose Red over Alexa. Can't be color. 

And not that it matters, but per my point, Alexa's not really 2K is it. 

[dbp]

I did one unpaid project helping a friend. Like you, I was curious, so I did a few shots with the GH4 and a few with the blackmagic pocket (pro res)

Both keyed well but the GH4 did better I think. Resolution definitely seems to be a factor. Used the GH4 again on a paid greenscreen gig with a much better lighting setup. Owner of the production company even commented on how good the keying was, and I didn't really have to work for it in post. Was pleasantly surprised with how well the GH4 does with greenscreening. I imagine the GH5 will be even better.

I kind of wish I tried raw on the pocket, though. A co worker at that same company showed me some tests with his BMCC on a greenscreen, and the raw seemed to do much better than the pro res, especially with tricky spots like long, messy blond hair.

Still, I'd lean towards GH5. 

[Rank Amateur]

On 7/30/2017 at 11:07 AM, Jonesy Jones said:

5. Use false color to expose your green walls to get it even. To be honest, that corner you've created with the 2 perpendicular walls is going to pose a pretty serious problem. That corner will be very difficult to light properly. If at all possible, build a short sweep to make that corner a curve. 

Thank you for sharing these green screen tips in such detail, Jonesy Jones. Can you elaborate on how to use false color to expose my green walls to get it even?

Thanks for pointing me toward Neat Video, HockeyFan12. Using the keyed layer as a track matte so that Neat Video doesn't effect the foreground makes perfect sense. (4K, Keylight, Neat Video... at this rate it seems it won't be long before I'm trying to make the case to my wife for a new computer as well as a new camera. :P)

I appreciate you sharing your experience, dbp.

My GH5 and Panasonic 12-35mm ii lens arrive today, so I should be able to weigh in with my own comparison between the two soon. I was convinced days ago when I read everyone's replies that the GH5 was the way to go, but it took me until yesterday to order one because I was deliberating endlessly over which lens to order for it. I finally decided I'd rather have the camera and start somewhere with a lens, since my "research"/obsessing over whether the lens is wide enough, fast enough, sharp enough, has dual IBIS (and whether I need it) could go on forever. Hopefully I made a good choice with the 12-35mm, though I'm nervous about going from an f1.0 on my previous setup (BMPCC, Metabones BMPCC Speed Booster, Sigma 18-35 1.8) to an f2.8, and would have preferred the option to go wider (the 24mm equivalent on the 12-35mm should at least be a bit wider than what I understand to be the 30mm equivalent of the Sigma's 18 on my previous setup).

That said, please let me know if anyone has any better lens suggestions for my primary application (shooting a 9' x 12' green screen with only a few feet outside of the "set").

Oh, one last question (for now, anyway), can anyone tell me the ideal settings for the GH5 for shooting green screen, e.g. which camera profile I should use? Thanks again!