Tuesday, May 17, 2016

Sony Diaries #948: Photography in the Operating Room

Excellent, concise article on OR photography,
by Levi Sim in Photofocus. 

Some added thoughts on the subject:
Working as a biomedical photographer in the OR, my focus is more macro 1:1 - 1:4, my photos being used for teaching  and research purposes. Since I have to shoot directly over body cavities, sometimes with only seconds to get the shot (30 sec is way too long in cardiovascular surgery), I have to work really fast.
Two points to add to the article:
1) Because I have to be standing  from a surgeon's POV (he/she generally moves half a foot sideways to accommodate me), I have to be extra careful I don't brush against the sheets (I'm not as sterile as the surgeon is), and so I  gently request the nurse to drape an extra sterile sheet on the spot where I could potentially brush up. Saves on replacing the whole sheets if I do touch anything.
2) I prefer not to go on a step stool while I point the camera directly over the body cavity. I get a strange unbalanced sensation, as if I'm going to topple over. I'm only 5'8" and really, I'd  need to be at least 6'4'' to get a good view. So I use a Sony RX10 with an tilt screen, with my hands extended while standing beside the surgeon. . What makes the tilt screen really useable is Sony's excellent Live View implementation. The RX10 has a 1" sensor so F8 is roughly equivalent to F16 on a FF camera (or something like that, I don't know the exact calculations). You'll need lots of depth of field! The lens is not a 1:1 macro lens but at 200mm, I can get as close as 10", which covers an area 3" across. Believe me, no surgeon will want you closer than that to anything.
The RX10 lens is a Zeiss 24-200 F2.8, sharp wide open edge-to-edge, constant aperture. The zoom range is suitable for any type of shoot, short of an architectural shot of the whole room! Only 1 small camera to take into the OR.
For lighting, I use the smallest ring flash that I am aware of, which does away with the power-supply-on-the-hotshoe of the typical ring flash. It's the Metz 15 MS-1, which is so thrifty with it's power use that 2 AAA batteries goes a long way.

OR lighting is tricky to handle, with harsh light with a white balance that is not compatible with the ring flash. Fortunately, the Sony RX10's AWB is amazing, and I slant the camera's flash exposure/AWB to favour the ring flash. While the fingflash is not a TTL unit, it does have a sensor that is quite precise (repeatable consistency). I also request the surgeons (there's at least 2) to look away for a few seconds so their head lamps don't add more light with another third colour temperature.

I'd like to try out the new Sony a6300 with the Sigma 30 F3.5 macro. While it won't be as versatile as the Sony RX10 with its unique lens, I can see the faster focus speed and a real 1:1 macro lens as a huge plus. And I can keep on using the Metz 15 MS-1!

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