Am I missing a setting that may help with a tough to shoot video scene?

[neosec]

Am I missing a setting that may help with a tough to shoot video scene? Or a better technique?

I use a 5D Mk3 with a 70-200 2.8 to shoot video at a race track. Typical settings...
1920/30 IPB, Manual, f16 (daylight) f5 (night), Shutter 250 (day) 125 (night).
As the cars circle the track they range from ~35 feet to ~200 feet which is why I need to stay stopped down a bit to maintain focus. At night I trade off some definition from the higher shutter speed for better exposure as it gets dark (the track lighting is poor and a mixture of HPS (yellow) and MH (white) lights. A white balance nightmare).

In an effort to expose for my subject, the cars, I use auto ISO during daylight because the cars drive in and out of harsh shadows from trees as they circle the track. This works quite well but it only useful during the day since the Auto ISO tops out at 12800. By the end of the night I'm shooting with a fixed ISO of 16000. This becomes a problem since I'm panning from poorly lit areas to shooting right into the lights.
I'm thinking switching to Tv mode at 125 and ISO 20000 and let the aperture handle the exposure, though I haven't tried that yet. Hopefully the very High ISO would keep the aperture stopped down enough to maintain the focus throughout the range.

Comments/Suggestions?

 

[risc32]

i really shouldn't say as video isn't my thing, but those settings f-stops and shutter speeds look way out of line to me. Do you really find that you need those values to maintain good focus? perhaps you are after the look given by those higher shutter speeds, and if so cool, but if that wasn't your goal, i would have thought something in the 1/60th range would be a more "normal" speed.
anyway, exposure isn't even what you are asking about, so i guess i'm no help. sorry, i'm sure people in the know will be along shortly.

 

[neosec]

Thanks for the reply.

As for the shutter speed, I read somewhere that for video the shutter speed should be twice the frame rate (30 fps in my case)as a rule of thumb. I opted for an an even higher shutter speed during daylight figuring that it would provide better slow motion with less motion blur in post processing, i.e. slow motion of a crash.

Edit: Only minutes after posting this I realized that I had confused my fps/shutter speed. a Shutter speed of 60 would indeed be double the 30 fps. I got the 120 shutter speed into my head because of a XH-A1 camcorder shooting at 60 fps on the other side of the track that I work with also.

 

[sjschall]

You're experiencing the limitations of using a DSLR for video work - while great for cinema applications they have big shortcomings in the event scene. Don't get me wrong, I use DSLRs for my event work too but there's not a one size fits all solution that will make your life easier. Especially when the exposure changes rapidly during one scene (like what you are describing, with the cars going in and out of shadow).

If you manually change shutter speed, ISO, or aperture in camera while recording you are going to get hard stops in the final video, no way around it. Some options might be to use a video camera instead such as the XH-A1 you mentioned, try auto exposure on the 5D and see how it handles, or just pick an exposure and stick with it, even as the cars go over and under exposed.

 

[neosec]

Ok, Thanks.

I'll give the Tv a try and see how it goes.

 

[crazyrunner33]

Magic Lantern would help combat the exposure changes with the gradual exposure ramp ISO. The focus peaking is also very valuable for focus assist.

 

[skoobey]

First of all, 5d is NOT an action film camera. Okay? In order to get professional looking shots, you need to do multiple takes of controlled scenes.

So, no, you're not missing anything, you're just constrained by the tool.

Try using a semi pro to a pro grade video camera, preferably shooting the raw, and it'll all be fabulous.

You notice how the F1 has different cameras for shady and different for sun light parts of the track? Multiple angles? This so you don't hunt focus from infinity to macro, and so you don't change camera settings mid-shot.

 

[Peter Forum]

Magic Lantern would help combat the exposure changes with the gradual exposure ramp ISO. The focus peaking is also very valuable for focus assist.

I think this is an interesting thread and deals with an issue I (and perhaps others) have been struggling with - that of making exposure changes while shooting. If exposure change is done manually then there is the visible hard change as the aperture or shutter changes.
Like a suggestion in this thread I've got around this partially by using auto gain, but this allows no corrections to deal with backlight or other exposure compensation issues.
I haven't yet tried magic lantern (my cameras are always professionally busy) but maybe I should find the time. Can you tell me if the gradual exposure ramping described above is readily accessible, so you could use it 'on the fly', perhaps with the thumb wheel?
Thanks.
Peter
5D 2 & 3

 

[neosec]

Well I finished up the racing season using Tv set to 60 with 30fps. Manually adjusted the ISO throughout the evening to achieve a target of f8 minimum (it would swing from ~f8 to ~f22 as I panned [bad lighting]). By the end of the night I had the ISO ramped up to 20,000 to maintain depth of field with the focus manually set and left untouched. This worked well zooming the full range of 70 - 200 each lap of the race cars. The results were much better that the video shot with XA-H1 shooting from the other side of the track. All in all, it worked out well for this event. I looked onto ML but no way I could zoom and focus each ~8 second lap.

 

[Peter Forum]

That's good that you worked out a technique that works for you, tho personally I'm always nervous about zooming while shooting as, you prob know, the 70-200 doesn't hold focus through a zoom movement.
I learned how to adjust exposure (limited to 2stops either way) while shooting by selecting av and then using the exposure compensation function which compensates with a gradual change. Fairly limited on scope but works ok for small variations in light.

 

[neosec]

That's good that you worked out a technique that works for you, tho personally I'm always nervous about zooming while shooting as, you prob know, the 70-200 doesn't hold focus through a zoom movement. ...

Right, that's what necessitated the need for keeping a high f-stop (small aperture). As the cars passed close to be they were a bit out of focus... for about a tenth of a second as they passed. This wasn't noticeable while watching the video, which by the way was SD quality on DVD disk.