Shutter priority and Auto-ISO - pros and cons

R

RandyQ

Well-known member
I will be doing a corporate shoot in a week or so for a fishing company in the Western Pacific. Its more docu-type shooting than anything else because I will be following some very fast-moving action.

Am thinking of shooting the video in shutter priority (to ensure 60fps) AND auto-ISO (720P 60fps). I DO shoot in manual mode, but thats for more controllable conditions of which this is not.

Any thoughts on this? Has anyone used this mode with any success?
 
I presume you're not aiming for a fixed aperture, so why not control this manually with the lens or front dial, if you're using an m4/3 lens.
I prefer to have the control over the image personally and don't find it a slow way of working. If you're shooting stills in shutter priority and need to switch to filming quickly, then there is a speed advantage.
 
I do it all the time for weddings...it works great. I shoot 1080/24p, so I typically set it at 1/50th, and as long as 1/30th for low light situations. The camera does a great job of controlling the aperture and ISO, since I have VERY little control of the rapidly changing lighting conditions. Then again, most of my weddings and receptions are in dark churches/halls, so the aperture often just stays wide open with the ISO max'd out, even with my camera light on.

Just remember, if the exposure changes during the middle of the shot, it's very obvious on in the video. I screwed up some shots this past weekend because I forgot I still had iExposure enabled, so the camera started adjusting the aperture even after I had set the Auto Exposure Lock/Focus!
 
My experience is that leaving the ISO on 'auto' always that it produced very visible jumps when the camera changed the exposure, even with the ISO set to 1/3rd increments.
I need to use an auto exposure method quite often and have now settled on 'shutter priority' on (1/50th in PAL lands) but setting the ISO to a fixed number...hopefully ISO 100 when possible. The 'Manual' mode of the camera then uses the aperture to adjust exposure and there aren't any visible steps.
A 2 /3 stop ND is pretty mandotory for video of course.
Best to have a camera pre-set, like 'smooth' with contrast etc dialled down so you can do exposure tweaks in grading later.
No auto exposure will get everything right (far from it) but it's faster usually than I can be and I can spend my time looking after the focus...which is fun with a camera that 'hunts' during filming very often if left to do auto focussing.
I therefore only switch to auto focus to grab something, before switching back to manual.
My Canon 5D2 can be left to auto expose using either ISO or aperture so it's a pity the GH-1(3) can't.
David T
 
AdrianF said:
I presume you're not aiming for a fixed aperture, so why not control this manually with the lens or front dial, if you're using an m4/3 lens.
Click to expand...

There are two locations during the shoot that I am very concerned that I will not have the time (or extra hand) to make adjustments - one of these is a shoot out on the ocean on a tuna boat, and the other is on the base when they unload the fish. I'm looking for ways to cut down on the work so I can focus on getting the shot.

Last time I did a shoot on a tuna boat, it was rolling so much that I always had to have one hand holding on to something just to get a steady shot.

Its quite similar during offloading - the crew moves so fast that you barely have time to react. While I could technically tell them to stop and redo, it will have to be in Chinese and I doubt that my Chinese is good enough for this.

This kind of shoot was very easy in the days when I did it with a PD170 - with a DSLR, it takes more thinking/preparation.
 
swyzlstyx said:
I do it all the time for weddings...it works great. I shoot 1080/24p, so I typically set it at 1/50th, and as long as 1/30th for low light situations. The camera does a great job of controlling the aperture and ISO, since I have VERY little control of the rapidly changing lighting conditions.
Click to expand...

Great to hear that. Are you shooting with the kit lens? Also, how is the quality at max ISO? Are the exposure changes STEPLESS or is there a distinct jump when it changes? I did some tests myself and it looked stepless to me at the time.
 
swyzlstyx said:
Just remember, if the exposure changes during the middle of the shot, it's very obvious on in the video. I screwed up some shots this past weekend because I forgot I still had iExposure enabled, so the camera started adjusting the aperture even after I had set the Auto Exposure Lock/Focus!
Click to expand...
iExposure is uncontrollable, but if you set ISO to Auto and hit the Exposure Lock button after you press the shutter half-way, you'll get a steady exposure for the duration of the shot. You need to be in Shutter Priority (or Aperture if you prefer) for this to work, since Exposure Lock doesn't work in Manual mode.
 
Last time I did a shoot on a tuna boat, it was rolling so much that I always had to have one hand holding on to something just to get a steady shot.
Click to expand...

This sounds like a difficult situation. You'll be at the mercy of the weather too. If the lighting is fairly constant, say overcast or clear and sunny, you should be able to set up a manual exposure or exposure lock if you've only got one hand free. If it's blowing and a combo of cloud and sun, then light levels will be changing super fast, so you might be better toggling exposure lock, if you've only got the one hand. Hard call.
 
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