Image stabilization through rapid fire April 22, 2008
Posted by tcbp in : Photography , trackbackIf you’re like me, and you don’t own a lens with Image Stabilization, Vibration Reduction or Optical Stabilization (I think I covered all the names out there) and your camera body doesn’t have any anti-shake features built in, you may sometimes find yourself in a tough situation. You’ve already maxed your ISO or don’t want to push it any further, and you’re in a location where you can’t physically or legally set up a tripod or grind your camera in to something hard to steady it. What do you do?
Having developed the habit of walking around with lenses that nobody in their right mind would consider walk-around lenses like my 90mm TS-E or 100mm macro lenses, I’ve had to come up with some interesting solutions to the hand-shake problem. I use a tripod whenever I can, unless I’m lazy (it happens). The next best thing to a tripod is rubbing the paint off your camera by mushing it in to something steady, like a big tree or the side of a building. Your friend’s head is probably not going to work in this case, unfortunately.
When all those options fail, the best hope for sharp pictures left is to take a lot of them. While that probably seems obvious in a way, the reasoning behind it and method, I think, aren’t as intuitive. The reason I say that is the method that works the best is turning on your motor drive and letting your camera blast away as fast as it will go.
My camera can fire at 8.5fps (so they say) so I set it for this maximum speed and prepare myself. Use your best hand-holding technique and body posture and steady yourself. As soon as you’re ready, roll your finger in to the shutter button as gently as you can. I usually let my camera fire for about a second (7-10 frames usually go by) and release the shutter button by rolling my finger off of it.
What I usually find is that the first and last shots are garbage; but somewhere in the middle, after the shake from pushing the button and before the often inevitable shake from anticipating the release of the shutter button, there is at least one sharp frame. As a result, using the motor drive works better than just firing a whole bunch of separate shots because you can just focus on staying still while shooting rather than pushing the shutter button. If you shoot JPG (shame on you) or RAW (compressed, losslessly of course) it’s quite easy to identify the sharpest frame: it’s the one with the largest file size. Hopefully you haven’t drifted so far off course that your composition has suffered; a common side effect of exhaustion, cold, or really strange shooting angles.
I figure it’s best to show some examples of this in practice. Some of these turned out better than others, as you’ll see:
100% view, 100mm lens, 1.3x sensor crop, 1/60th second hand held
The image above isn’t pushing this technique too far. Following the old rule of thumb, you want to shoot at 1/focal length as your shutter speed. Since many people consider the crop of their sensor in determining that you’d want to shoot at the reciprocal of your focal length times the FOV crop. In either case that means I should shoot at 1/100 or roughly 1/130 respectively. Instead this was shot at 1/60th hand-held on a rather cold day. Since this was the first shot in the sequence I probably could have gotten away with acceptable results without the motor drive, but whenever I’m in questionable territory I let it run anyway.
100% view, 90mm lens, 1.3x sensor crop, 1/30th second hand held
For this shot I believe I was leaning against the wall, and relying on the motor drive, to ensure a sharp shot. In spite of the shallow DOF the area in focus is sharp.
100% view, 90mm lens, 1.3x crop, 1/15th second hand held
Finally, pushing the concept entirely too far, this was shot kneeling on the ground aiming up at the ceiling with the camera balancing on my face and hands. I believe some of this softness is due to poor focus. The light was low, I was at a large aperture and although I had the lens tilted to try to get the plane of focus to fall on the ceiling, it was very hard to judge in the low lighting.
Give this a shot if you have a camera with reasonable frame rate. I imagine if you’ve got at least 5 or 6fps this can work fairly well for you.
100% view, 100mm lens, 1.3x sensor crop, 1/15 second hand held
First frame of burst on on the left, last on the right.
The above image(s) were quickly shot while I was sitting in my chair just a few moments ago as an illustration of how this works. Like the rest of the 100% view images, no sharpening was applied to this. The camera was set for 8.5fps and I fired a four frame burst. At 1/15th second the framerate isn’t really 8.5fps so I think if you’ve got 5 or 6 fps this will still work. This method obviously doesn’t always work, and it’s not without its flaws, but it does come in handy at times.
Here are the sharpened 800 pixel full originals for the first three 100% view crops shown:
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[...] IS works beautifully. I certainly can still use the rapid-fire stabilization method I’ve written about before but IS does make it a much easier general purpose lens to use in a variety of [...]