chromakey tests, anyone ?

Lenny, I've reuploaded a more polished version as the same file, feel free to check it out. There's a tiny hint of magenta, but I wanted to stay in the realm of a one layer same setting key for the whole shot. FYI, the key settings are exactly the same on both sides, 35 Mb and uncompressed. The only difference is a slight gamma inbalance between the HD-SDI capture and the codec mapping.

My overall impressions are that the codec blooms the blue channel a bit compared to the HD-SDI, and that the HD-SDI retains a bit more resolution for detail in the chroma areas and there is less noise in the marginal areas of transparency. As I'd hope for that increase in data rate.

However, if this is acceptable to you or not, it does nothing to help you or your client out in the decision making process. All it does is say that some guy in Colorado shooting under the worst possible lighting conditions did an okay matte on a solid grey background. The only thing that would matter to your client is how good you light, and your people comp. I would put forth that I don't think the camera will be the thing standing in anyone's way.

Finally, since this is very important to you, and you're not yet seeing something worth selling in the area of keys... what camera ARE you currently using that is adequate for your client? I can dig you up some F900, some RED and Viper frames that suck toe compared to this latest version of the comp...

As to PP settings, I'm experimenting now with some, and will be in the snow tommorw for some tests... I don't know enough about the Cine settings to like or dislike them yet.

Regards

Jim
 
rubento said:
Jim,

Could you share your PP settings for your Chroma key test? I found it very, very good...

Thank you
Click to expand...

Gosh, it was literally in the first hour of testing the camera, the only modification was turning off the detailing entirely and -3db. Currently I've shot a couple jobs with a PP modified to -4 black and Gamma set to STD 3 and that seems a fine "safe" set of options. -4 on the black seems to push the darkest black (lens cap closed) down to -just- before crushing at 0 IRE... -5 might be too much.

As I mentioned in the last post, I'm going to experiment with some Cine settings tomorrow... I'm just using this as a starting point for the tests...

http://provideocoalition.com/index.php/awilt/story/review_sony_pmw_ex1_1_2_3_cmos_hd_camcorder/P3/
 
Jim,

Forgive me for being so dumb about keying.
I take it you are saying that with a little bit more work and an extra layer you could easily remove the remaining magenta fringing right. That's typical for a shot with fine hair anyway isn't it. I take it those are never easy.

- Lenny
 
Yes with another shot at it, and that color (magenta) is an issue only with blue screen, not green screen. It is NOT a camera issue that could be fixed by better glass, etc. I'm sure the low CRI lights with their incomplete spectrum are bumming up the mix more than anything else.

The only real point I'm making with this shot is that if you factor all the handicaps into the equation; low color temp forcing the camera to drive the blue more than normal, incomplete color spectrum, blue screen being more difficult than green because of blue channel noise in general... it just seems to me that we've got something a cut above anything in the price range and a bit higher.

Or as I like to say to clients on set when I pull a quick key to test the lighting setup, "This is as bad as it will get. It will only get better.".
 
Jim, you did that on blue, not green screen? Egads! Sure beats the heck out of HDV! You're inspiring me to play with the green screen keying again.
 
The problem with testing against the RED is that it is constantly a moving target with the firmware updates. When I did a day with RED 232 doing blue and green screen tests, it was clear that the camera was very challenged in the blue channel under tungsten illumination. This impacts not only blue but green screen work as well. Here is a test I did that shows clearly those issues...

http://ftp.datausa.com/imageshoppe/outgoing/RED_232/blue_channel_compare.png

Now, as I understand, there's new improvements in the firmware and also different quality settings for REDCODE, so it's all up in the air again and would require re-testing. Which is a great idea when I get a free day to do so.

At the time, there was no question, even with the super-sampling down from 4K Bayer to 2K 4:4:4 that the EX1 4:2:2 is/was a competitive performer in the keying department under tungsten lighting.

But hey, feel free to have a go with our RED key source footage (girl with bunny)... just download the clips, fire up REDCINE or REDALERT and process your collective hearts out...

http://www.redrelay.net/owners/0232/
 
Jim, it appears from your results the RED ONE camera's CMOS sensors seem to be balanced for 5600K.

I imagine the EX1 sensors are balanced for 3200K.
I believe this is one reason why the EX1 would fair better in the blue channel.
Those RED ONE results surprised me. Thank you for posting.

If so, I wonder why they chose a 5600K balance?
3200K lighting is plentyful, not to mention all the conventionals in standard lighting.
 
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