First video with A7s – testing Slog2 and noise.
Santa was generous last year but we didn’t have the time to fully test all the gear we got the previous year. Friends of ours (Hardstyle DJ’s) asked us to shoot a trailer for one of their party so we decided to take the occasion and test the dynamic range, Slog workflow as well as mounting the A7s on our Eemov Hawk Steadicam. The location is the incredible railway museum of Ljubljana. As you can see, it’s a good spot to test high dynamic range.
We used a Samyang 35mm 1.5T lens and polarizer Hoya circular 77mm HD for all shots. We filmed in Slog2/Gamut at 3200 ISO, shutter 125, 1080 60p on an extreme 64G (45MB/s) SDxc I card from Sandisk. At this time we didn’t have the Movcam cage yet but we did have the Vizelex Throttle lens adapter with ND from Fotodiox.
We set our A7s on Full Frame sensor mode and APS-C for few close up as we hoped we could use the crop factor to give our prime lenses a “x1,6 extender”. Footage was imported in Premiere in a 30p sequence because most of the film is in slow motion (we would reduce the speed at 50%). We graded with Filmconvert (using camera profile A7s Slog2/gamut and film setting FJ superX 400). The export is a Premiere preset (youtube preset HD 1080 30p).
Our main concern for this video was to try the workflow of A. Chapman (www.xdcam-user.com). We overexposed (according to the A7s light meter) from 1 to 2 stop. We did external (using the ND on the adapter) and internal shots. We follow the EV +2 rule and had good results. Inside we tried two situations where we placed characters in shadows in front of big windows. In the first shot we had EV +0,7 and filled a bit with the Led panel. In the other shot we had EV 0 and used no fill light. In the first shot the level of noise was acceptable. In the second case the level of noise was at the edge and there was no room for bringing up the shadows.
We noticed more noise for the APS-C mode in low light than in FF mode. Overexposing in Slog2 from 1 to 2 stop is necessary in order to preserve blacks from noise. The dynamic range is fantastic but the internal 8 bit rate codec doesn’t allow intensive grade. The XAVCs codec is good enough for light projects but for more complex editing and grading work, we will first have to test what we got through an external recorder like Shogun.
See also NEW CAMERA: A7s