Low-Light Action Shots (in need of some help)

midnightradio

I'm an amateur photographer who is slowly turning my love for the craft into a second career. My primary focus (no pun intended) is on performance photography, mainly theatre. Recently I've been having trouble achieving very sharp images, and I'm looking for some guidance as to what I'm doing wrong.

My primary body is the Canon 7D, also using my older Rebel XTi as a second body. I use the Canon 70-200mm 2.8 IS II and 17-55mm 2.8 IS lenses, varying which lens goes on which body depending on the size of the theater. The majority of my shots with the 70-200 are very sharp, which isn't quite the case for the 17-55. I used to shoot mainly in aperture priority mode, but have recently forced myself to learn to operate in manual - I try not to shoot slower than 1/125 (to stop the action), and not higher than ISO 1600 if I can help it.

I like to keep the aperture at 2.8 (since I'm using these very fast lenses!), but I'm having trouble compensating for depth of field when all the subjects aren't on the same plane. Is there anything to be done, when shooting with a fast lens in low light, when you want all the subject to be in sharp focus? Shooting at 2.8 doesn't seem to be the answer, but I lose the fast shutter speed ability when I bring the aperture down to 5.6 or so. I do shoot RAW, but even Lightroom can't recover that much underexposure.

I'm guessing this is one of the primary reasons for my lack-of-sharpness problem, though I'd be curious to hear if anyone can think of what else it might be. Metering? I've never had success metering in anything other than evaluative, and I usually don't risk trying at a fast-paced shoot where I can't afford to lose a couple shots experimenting.

Any thoughts are greatly appreciated!

perroneford

There are only three pieces to the puzzle. ISO, Aperture, and shutter speed. If you need another stop of aperture to get more depth of field, you must sacrifice ISO or shutter speed. If your subjects are moving, then shutter speed likely isn't the answer. Your option is to add more light (flash) or add more ISO.

This is a primary reason people purchase expensive full-frame cameras with excellent low-light performance.

pathfinder

Perroneford really nailed it, there are only three variables, ISO, aperture, and a suitable shutter speed. You cannot shoot at small apertures in the dark with short shutter speeds. You CAN shoot in low light at small aperture and low ISOs if your shutter speed can be long enough, but that requires a tripod and stationary subjects.

What ISO are you using on your 7D? If you avoid under exposure, ISO 1600 should be quite useable, and almost noise free. I would avoid ISO 3200 if I could, but I do have some wildlife shots captured at ISO 3200 with a 7D that are acceptable given they were shot 40 minutes after sunset.

Shooting in theatrical lighting can be challenging. The light intensity can vary greatly, and you almost have to meter for the highlights, and let the shadows go to black.

A shutter speed of 1/125th should usually be adequate with the 17-55 f2.8 IS lens, shooting handheld. Could you use a monopod, if camera motion is part of your issue?

IF you need f2.8 to capture the light needed for proper exposure, you will not, and can not capture great depth of field. If additional depth of field is a must have at f2.8, going to a smaller sensor, like a m4/3 camera will help you with a little more depth of field. Cameras like the Olympus OM-D E-5, and the Lumix GH-2 or GH-3 can shoot at iSO 1600, and do have some nice primes at f1.8, and Panasonic make a very nice 12-35mm f2.8 lens that is quite sharp. Smaller sensors have greater dof for a given focal length.

But if you are under exposed at ISO 1600, f2.8 and limited to hand held shutter speeds, your only option remaining is to add some more light either with flash or reflectors, and the theatre director will not like that unless you could do it during a dress rehearsal.