Alexa open gate recording (6 replies and 3 comments)
I think you are familiar with Alexa open gate recording. I heard Some of the wide angle lenses like cooke cause vignette edges in frame while shot on open gate. What's your opinion about this artifact?
Some lenses do not cover open gate so you have to be a little careful. Some zooms at the wide end vignette as well and you see this all the time. My opinion of the artifact is that it is an artifact.
When you shot first time on open gate how did you decide the cropping area won't affect your composition elements. Because both side should crop in post. Just you did any aspect ratio masking on monitor for your judgement or just you shot full frame and leave the monitor as it is. What brand calibrated monitor usually you using in digital.
i don't understand what you are asking here. What do you mean by cropping in post?
Here cropping means you had shot "sicario" on open gate mode. How did you achieve 1:2.39 from open gate ratio. When you shot on open gate mode how did you plan compose for 1:2.39 instead of full sensor.
There is no difference in shooting for 2.39 or 1.85 with the camera set in a standard mode to shooting in Open Gate. It is equivalent to shooting for 2.39 in Super 35mm rather than in standard 35mm. You crop the top and bottom of the frame in every case as you image area, whether it be a sensor or film emulsion, is larger.
Lingam, here's a screenshot of some behind-the-scenes from Sicario. There are widescreen guidelines on the display itself when shooting, but the full 1:55 open gate-size image is recorded, which, I believe, also gives some leeway for some adjustments in post.
Shooting an image on a format that records more picture information than the composition is nothing new. 4-perf 35mm film started out in the Silent Era as full aperture, meaning the whole negative area was used for the picture, but once sound-on-film prints came along, the left side was trimmed by the soundtracks so viewfinders had to have frame lines that took this into account, and then when the "matted" widescreen formats of the 1950's came along and gave us the 1.85 : 1 ratio, even more of the 4-perf 35mm negative was being composed for cropping top & bottom. 8-perf VistaVision has a 1.50 : 1 shape, similar to Alexa Open Gate's 1.55 : 1 aspect ratio, but those aren't aspect ratios used for movies or TV, so some portion of what gets recorded is cropped later -- the main thing is that you COMPOSED your image within that cropped area.
Here's an old copy of the viewfinder frame lines used for "Terminator 2", an early Super-35 film:
In terms of vignetting due to the lens coverage not being large enough for the sensor area being recorded, sometimes if the vignetting is minor enough, just in the corners, it falls outside the widescreen frame that you are composing for -- this is especially the case when you are cropping to 2.40 : 1. I drew this to show how the lens coverage circle can come into Open Gate but still just be out of 1.85 and 2.40:
Nice explanation Mullen