The night before this video shoot, I decided to shoot in 4K. The primary reason being that I will have to crop in severely, in post. For sterile reasons (not being able to get closer to the scene), and depending on the procedure, I may end up using only 1/10th of the field of view. .
I had my reservations on my post-processing gear. My iMac's 16Gig RAM is the minimum required for editing 4K, according to the experts. I thought I'd take my chances But the bottom line is that I could always convert my 4K footage into 1080P before starting the editing process.
The image field in the OR is notorious for high-contrast lighting; so another consideration was whether or not to shoot in SLog2. Slog2 is a gamma curve with a wide dynamic range optimized under the assumption that grading will be performed in the post-production process. SLog2 allows for precise reproduction of gradation characteristics in the shadows and in the mid-tone range. It shoehorns a wide dynamic range (high overall contrast) into a manageable range (flat contrast), that is restored in post-processing to a contrast range the way the mind perceives it to be. The nice thing about the Sony A7III camera is that it has a feature, AUTO ASSIST, that simulates what the S-Log2 footage would look like after post-processing. Otherwise, when the on-camera AUTO ASSIST is turned off, the footage will look very flat. SLog2 starts with a base ISO of ISO800; this high ISO wasn't a concern since I knew I'd be shooting for deep depth-of-field, typically F8-f16 (negative diffraction effects start around F16).
I'm shooting SLog2 instead of SLog3 because apparently, SLog3 is optimized for 10-bit cameras such as the newly released Sony A7SIII. SLog2 is recommended for 8-bit cameras such as the A7III, which is what is available.
These are my settings for 4K (default settings apply except for the following):
XAVC-S 4K, 30p 100M, XAVC-S HD 30p 50M... Priority Set in AF-C: Balanced Emphasis... Focus Area: Zone... AF Track Sens:4... Picture Profile: PP7... Black Level: 0... Gamma S-Log2... Color Mode: S-Gamut... Saturation: +24... detail Level: 0... Audio Rec Level: 12 (for inboard mike), 1 (for RODEMIC PRO.
The shoot in the OR lasted 7 hours, requiring 3 64gig cards, and 3 Z-type batteries (I switched batteries with 25% remaining). Some clips were shot one-after-another, with some clips lasting over 20 minutes each. When the camera shut down due to overheating for the 2nd time, I decided to switch to 1080. on 4K vs 1080P, there is a marked difference in resolution on my monitor; there is no discernable difference on the web-optimized final product for streaming purposes.
Looking back, and for future OR projects, I'd prefer a smaller, lighter, crop-sensor body without a recording limit such as the Sony A6600, with a lighter lens such as the Sony 18-105F4 lens. The Sony A6600 has the added bonus of having a fully articulated finder. This camera/lens combo will have 5-axis stabilization and will be reserved solely for OR shots and for other assignments requiring sterile conditions. I'd also use a lighter monopod.
I'd also recommend donning the same sterile garb as the medical staff; this way, I don't have to worry about touching any sterile surfaces to get closer to the scene.
My fears for computer processing were unfounded. My current iMac hardware specs handled the 4K editing nicely: 2.9 GHz Quad-Core Intel Core i5, 16 GB 100MHz DDR3, NVIDIA GeForce GT 650M 512 MB, 500 GB SSD. Rather than having all my working files on the 500 GB SSD as recommended, I worked on files in an external SATA hard drive via USB3.0. I didn't notice any lagging in performance using 2019 Premiere Pro.
Finally, shooting video in the OR requires stamina and flexibility. The use of a tripod/boom is recommended so a strong, healthy core really helps. So does a hearty breakfast.
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