To Jan Crittenden: HVX-200 Green Screen Halo Problem

[Per Holmes]

Hi Guys,

This is Per. Well, thanks for backing up! I did feel that a lot of people stepped in to defend issues that didn’t really need to be defended, this is just a scientific inquiry!

I only have to add that this is not a matter of having too high expectations by comparing the HVX-200 to 35mm in a blanket kind of way. My personal reference IS in 35mm scanned to 10-bit log at insane resolutions, so I’m used to ideal conditions.

I don’t expect this from the HVX at all. My concern was that the HVX exhibits a problem that I’m not entirely convinced HAS to be there, and which could possibly be corrected in software. I analyzed the problem to be a sort of chroma echo that I’ve been able to basically remove in software using a certain pixel shift process to offset part of the chroma signal.

My concern therefore was that the green screen quality of the HVX could be improved by a firmware upgrade to whatever DSP they use to process the raw CCD data. And that would be in everyone’s best interest! If the camera CAN do it, I think it SHOULD do it. Especially if it’s software, not hardware.

I don’t think that comparing a camera to 35mm should be off-limits. Certainly, in the most overall and general way, the HVX will not be able to stand up. But with a specific issue, the comparison can’t automatically be brushed off with the broad (and true) observation that the HVX can’t in GENERAL be compared to 35mm.

I’m convinced that the fringe doesn’t have to be there, and that the camera is capable of producing a better image than it does with the same hardware. I back this up with Andromeda footage I’ve seen that doesn’t have the fringe. But I’ve been able to reverse it enough that I’m fine, and I’m actually quite proud of what I’ve done with the HVX green screen. In fact, I don’t think that my 35mm green screen is THAT MUCH better than the HVX green screen when the signal is properly treated. I also don’t rely on the HVX, and this is sort of just a toy for me. Still, if it CAN be great, there’s no reason why it shouldn’t.

Anyway guys, thanks for your support!

Per

[Andrew Shanks]

Hey Jeremy,
I wasn’t comparing the two in terms of quality, totally different platforms, …I mean when you look at the glass alone, you get what you pay for, …what I meant was when being used to other formats (maybe i should have said from Digibeta or ENG DVCPRO50 cameras, apart from glass and sensor size they’re closer to the mark) and keying (where you don’t have to chase your tail finding a solution to fringe issues), it is a shock to the system to have footage you now have to waste extra time dealing with fringes due to the way it has been captured (its akin to being given footage that the client wants graded, …then you get it and you find theres a ton of wires that need removing as well), …as a compositor you get handed all sorts of crazy bad footage, and you have to deal, thats our job, …but as Per says, if there’s a way to fix it easily in firmware, why don’t they, they’d find a whole new market for their cameras if they did (as a pickup fx camera for elements).

I’d be interested to see what results can be got out of the component feeds, if nothing else it would soften the problem by going through D to A and back.

Will be interesting to see what the new 200A and 170 models footage is like with the new sensor.

[Jeremy Garchow]

[Andrew Shanks] “but as Per says, if there’s a way to fix it easily in firmware, why don’t they, they’d find a whole new market for their cameras if they did (as a pickup fx camera for elements). “

I totally agree. When I return from NAB I can send ya some still frames or even movies if that helps.

Jeremy

[Jeremy Garchow]

Excellent points well taken, Per.

Jeremy

[Andrew Shanks]

Would be great to hear your impressions of the new camera’s, i’m especially interested in the 170. I have to say the old pannies still have one big edge over even the RED, they don’t have the rolling shutter issue (CCD still kicks butt until CMOS technology can address that issue).
Look forward to your news from NAB 🙂

[Jeremy Garchow]

All the new variety of the Panny cameras are nice, although I will stay away from the new “AVCCAM” models. I am sure they are fine for some, just not for our needs. The 170 looks pretty cool, and now has SDI out which makes live capture soooo much easier. It’s quite smaller and lighter than the 200. It’s more like a dvx100 but a bit bigger. What’s cool that is at NAB you can see almost all of the cameras setup, pointed at a lit set with actors and watch a monitor of all the cameras right next to each other. My favorite was the HPX3000 (of course) the images coming off that camera are fantastic. I saw the 2700, but not the 3700 (I might have missed it, but I didn’t think it was up and running at NAB). I still liked the 3000 and I bet the 3700 will look just as good.

I will have to dig up the informal 200 green screen tests today and hopefully I can post some pics.

Jeremy

[Brett Frame]

Hello All,
We just picked up the 200A and have a project coming up that will require some green screen. Has anyone seen an improvement in the 200A over the 200 with the halo?

We use After Effects for compositing but we have Shake, though have not gotten our feet wet with it. The fix that Per spoke of about half way down this post… does anyone have a similar fix using Shake?

Thank you,
Brett

[Elijah Lynn]

Hi Jeremy,

Can you post these stills from the HD-SDI output to ProRes?

I am thinking of getting an HPX 170 for run and gun, interviews and keying and was going to do the keying uncompressed into a Kona. I have had nightmares with an XL2 exhibiting this EXACT same problem. I thought it was just 4:1:1 color space. A 4:1:1 color smoother helps a bit but not much.

It is odd that this camera is doing the exact same thing as a Canon XL2, and on the right hand side.

I am thinking that if it can be eliminated by a uncompressed output then I may be able to live with it and enjoy the built in vectorscope and waveform monitor but if this is the way the footage looks then I may have to think about the EX1.

That would be great if you could upload a side by side shot of ProRes vs DVC Pro HD.

Thanks

[Elijah Lynn]

How can I contact you?

I would like to speak with you regarding this issue.

[Mike Edge]

I have the 200a and while I admit to being relatively new to green screening (I use After Effects with Keylight 1.2), the right side of the talent looks consistently worse than the left side. Up until today I figured it was a result of my inexperience and perhaps the lack of a higher-end keying program but it looks like lots of other people are having issues. There is always a pixelated greenish-white border around the peoples’ bodies (although their hair is significantly better). This issue is especially present under their arms. However, this could just be because I don’t know Keylight inside and out like most of the posters here seem to know their keying programs.