- This topic has 5 replies, 6 voices, and was last updated 13 years, 11 months ago by .
-
Posts
-
Hi FX people.
I am trying to establish a pipe-line for Effect / Green screen work. Up until now I have been using interlaced Digibeta, IMX and HD-Cam (sometimes when being really lucky 35mm.., -gotta love that format).My favorite being IMX, progressive 50mbit with a high shutter for minimal motion blur (added later in post).
Some time ago I read something about extracting data from a relatively cheap camera straight to a raid system bypassing the tape and thereby compression. Also described below using the Sony CineAlta. Have any one of you worked this way?
Ok, what if I want something better, but HDCAM SR, 4:4:4 being too expensive…? What do you guys work with?
Short info from the article about the job for Association of American Railroads, (AAR).
“HDCAM SR would be perfect, 4:4:4 is the best you can get today, but was too expensive. Varicam did not seem to be the right format for many reasons, as there needed to be greenscreen. The only format seemed to be 720P at one point and after doing tests it showed me that is also too noisy. I thought of HDCAM, but what about compression? HDCAM compression seemed to be too high for greenscreen work So we finally arrived at connecting a D5 deck to the uncompreessed DH-SDI output of the Sony CineAlta camera and that produced the best possible image within the budget.” explains Wolansky.Kind regards,
/SamsoeMy experience with highly compressed footage like the one you mention, is not very good, even when you see a very nice picture, the compression is there, and when you apply the keyer, you will see all the artifacts that you don’t normally see, I personally do not have any experience with IMX, but I think that 50mbit is not enough if you need a very good result on a green screen job. But of course all depend on what you doing and what you need it for. I would be very interesting to see what other people think.
we have an F900 in house which im about to do some tests with…however..the silicon imaging camera [http://www.siliconimaging.com/DigitalCinema/SI_2K_key_features.html%5D “seems” impressive considering its cost…and the full res sample greenscreen images on their webpage keyed WAY better than the F900….anyone know where i can download a few uncompressed greenscreen frames shot with an f900?
Still the best is 35mm film on 5217/5218 stocks. However, the new camera from RED is looking extremely promising. Also, I have found that the actual greenscreen paints make a huge difference in keying. Rosco…good.
we recently turnkeyed a project that involved shooting a lot of greenscreen. it was for people walking around in a stylized holiday world, so there was a litle bit of wiggle-room for execution. we really wanted to use HDCAM-SR but didn’t have the deck in-house and the cost of renting one for even part of the project was prohibitive. instead we opted to shoot with sony 950 4:4:4 camera and pull keys in realtime using an HD Ultimatte. the ultimatte took the dual-link HD signal from the 950 even before it went to tape (which compresses it even further). it was absolutely the best possible color fidelity signal we could get without bumping up to a crazier camera like the Viper. the keys worked amazingling well. the operator was even able to extract excellent greenscreen keys with green-hued foreground subjects.
the best part about it was that by viewing your matte channel in realtime you could interactively see the effect of bounce/spill on your subject. the gaffer & DP could look at the monitor and see problem areas in the key that could be fixed quickly by hanging an extra flag or laying some black on the floor, etc……things that you can never see with the naked eye (especially after you have been in a greenscreen studio all day and your vision is messed up).
as a workflow we recorded 3 tapes simultaneously with matching timecode: an HDCAM-SR camera master to a SR1 field deck, a color-corrected “front” or “fill” pass on regular HDCAM and a matte pass on HDCAM as well. we were able to ingest the HDCAM back at the shop but always had the SR tapes as a backup in case we needed them. we never needed them. the front/matte combos pulled by the ultimatte operator were nearly flawless. in the end it probably saved us days of FFI time that would have been spent in keying (in addition to the human actors we shot literally dozes of products on a turntable on greenscreen, some very reflective and some very transparent).
as a test we dubbed the HDCAM-SR tapes to HDCAM and pulled keys in FFI using traditional ModularKeyer and MasterKeyer techniques. we were able to get good keys, but the compression in the HDCAM signal resulted in poorer edge detail and a fair bit more noise overall. ultimately we feel we made excellent workflow choices for the project and would use the UltimatteHD setup again in a heartbeat.
also, on the subject of greenscreen paint…there is a HUGE difference between chroma green and ultimatte green and digital green. the single best way to evaluate a fabric or paint is to look at it thru an HD waveform/vectorscope. Composite Components (http://www.digitalgreenscreen.com/) on the west coast is regarded as having the best stuff in both paint and fabric, but it is also the most expensive. second runner up would be roscoe ultimatte green. if you are using the HD-Ultimatte you can literally see the quality of screen in little saturation or “confidence” meter on the operator’s console. the better screens/paints have very high green purity values and it shows in your keys.
good luck
k
Thank you all for contributing to this thread. Very interesting to see how you work with greenscreen material.
On my project we are going to use 50mbit IMX, 25fps progressive. I have used it before and its fairly good if you turn up the shutter to minimize motion blur etc.., -and of course GOOD lightning is essential ;o)
kalthans, Is it possible for you to upload /email me an image from a 4:4:4 camera in full resolution / Quality. Would love to do a test key here at the office.
Kind regards,
/Samsoe
- You must be logged in to reply to this topic.