I'm to take pictures at a boxing match, probably under low lights conditions.
My plan is to set the camera on a fixed shutter speed, and the let the camera automatically set aperture and ISO. But how slow can I safely take the pictures. I hope I can bring my tripod, so it's not as much a question of camera shake, more a question of catching the action.
My equipment is a canon EOS 500D and a Canon 24-105mm f/4L IS USM lens.
Any speed will give you something. It will render the photo differently.
So, the question should not be how slow can I take the photo? but how slow do I want to take the photo?
Some ideas:
You'll have to try a lot but you are right about using Shutter-speed priority. You may want to fix the ISO and let camera play the aperture if you do not want all your shots to be at F/4, since most cameras prefer opening the lens than raising the ISO when light is low.
I recommend leaving your tripod at home. I can take pictures at 1/60 or 1/100 without noticeable camera shake. If you're taking pictures faster than that anyway, it would just slow you down.
The more skilled you become at shooting action shots, the more you learn to use slow shutter-speeds and use the subjects' motion to highlight the important activity and give the image impact. At a slow shutter-speed, you should, with practice, be able to completely blur the boxers' arms, legs, boxing-ring, and audience, but capture that moment when glove makes contact, making it the most sharp and abrupt part of the image. In this case, pun intended, a real moment of impact. Using the motion blur to frame and focus the most important part of the image, leading the viewer's eye there. Not unlike the same way that shallow DOF is used to isolate a part of the subject from foreground and background, but in this case it is accomplished with motion-blur.
This takes practice with both knowing how to quickly pan and follow a subject as well as knowing your subject to know how it will move, and the limits of how each movement might stop abruptly or halt motion during a sudden change of direction. Examples: snapping off a shot at the peak of a jump, or when a football player makes a 180-degree turn on the field, when a baseball hits the bat. (These skills are also invaluable in wildlife and birding photography, but then you must also know animal behavior as well as you might know human behavior.)
Too often people assume they need the highest shutter-speeds for action photography, when actually some of the best shots ever taken of these kinds of subjects were with slow shutter-speeds and low ISOs.
SHOOTING BOXING MATCHES- You can get acceptable images with a shutter speed of 1/320 although faster is better. Tomorrow I am shooting my third boxing match from the edge of the ring with a Nikon D7000 crop sensor. The boxing ring is somewhat dark being lit by a single overhead florescent strip. The challenge is getting enough light.
On the first boxing shoot last Feburary I had to set ISO at 3200 (high for my D7000), with an aperture of f/3.2, for depth of field, on my Nikon f/2.8 17-55 lens and a shutter speed of 1/320. The images were dark and grainy but were acceptable after processing in Lightroom.
Shooting my 2nd boxing match I opened the lens to f/2.8, 1/320 and ISO 3200. The added light from changing the f/stop from 3.2 to 2.8 made a noticeable difference in image brightness and color.
Tomorrow I’m shooting my third boxing match and plan to use my f/1.8 35mm prime lens and shoot it at f/1.8, 1/400 and ISO 1600. As with the first two matches I can shoot from the edge of the ring and can get good prespective with a 35mm lens.
I think the wider aperture will still give me adequate depth of field while allowing me to half the ISO from 3200 to 1600 and bump the shutter speed to 1/400.
My understanding is the larger f/1.8 (vs. f/2.8) aperture will give me 1.3 additional f/stops that should equate to enough additional light to handle the drop in ISO from 3200 to 1600 with enough light left over to bump the shutter from 1/320 to 1/400.
Two other points- On the first match I carried both my Nikon D7000 and a Nikon D5100, each with different lenses. The focusing/metering system in the D5100 is good but not quick enough for the instantaneous response necessary for timing boxing shots. I believe the Canon Rebels are comparable in response to the D5100 and Canon’s quicker 60D and 7D are more like Nikon’s D7000. Another point- Nikon’s are pretty good at recovery of detail & color from dark shadows in Lightroom.
"How slow" is somewhat subjective, as the acceptable amount of blur for me might be different for you. It also depends on how far your subject is from you. Because of these two factors, a specific shutter speed is not what I would recommend looking for. Instead, and since you are shooting digital - simply experiment and see what shutter speed works best for your needs.
Very generally speaking, I would start at 1/125s second shutter speed and work faster from there. You could potentially need as fast as 1/500-1/1000s to freeze very fast motion. I would say a safe bet would be 1/250s, but your results will vary. Depending on the match, some movements could be very fast and you might want every bit of the subject sharp, if that is the case you will be testing the limits of your equipment with certainty. If the routine is a bit slower or you find a bit of blur in the extremities acceptable, this should be quite achievable with your kit.
What you may find, is that you are forced to shoot at 1/125s because that also requires either a very narrow depth of field, or a very high ISO that is too noisy for your tastes. Again, personal preferences play into this.
Keep in mind also that some motion blur can be an artistic effect that adds to the image. Especially if you can shoot with a flash(but maybe you aren't allowed to), and use second-curtain sync.
Finally, why not browse through some Flickr images and examine the shutter speed used? Nothing beats real world examples to show the differences: http://www.flickr.com/search/?q=boxing
Here are some examples at varying shutter speeds. These are of a soccer game, but the same idea applies. These are all pretty poor images unfortunately.
18mm, f/3.5, 1/40sec:
50mm, f/2.8, 1/125sec:
18mm, f/3.5, 1/500sec:
