I'll be among the first to admit that image stabilization is pretty cool when it comes to objects that aren't moving. I love using my image stabilized lenses or cameras, or lenses and cameras when I'm photographing subjects that are at rest. Stationary. Not moving. Moving slowly. I.S. is a feature that helps me handhold my camera and lens system at lower shutter speeds than I usually would be able to without it. How much better is I.S. than photography without I.S. ? That really varies from system to system and even from format to format.
I think most would agree that Olympus is the master of this feature. I used two Olympus EM-5.2 cameras a few years ago to create a video for a restaurant and my accomplice and I were able to do the whole project handheld. All the takes were as smooth as you could want and in the ensuing years I've been asked by friends in the video production business which gimbal we used to do the project. Some cameras were far less convincing with their image stabilization; the Sony a850 featured Steadyshot Inside but I'll be darned if I ever got more than one and half stops of assistance from that 2009 vintage camera. More recently I was using various Sony cameras and I found that the least effective implementation of image stabilization came in the A7Rii. The I.S. in the APS-C a6500 camera I used over the course of a week was much better at stabilizing images than my full frame sensor cameras at every focal length I tested, but the real winner in the Sony systems (in my experience) was the RX10 iii. The RX10 was nearly as good as the Olympus cameras and was very useful in the video and photography.
For a while I was very enamored with I.S., whether it was lens or body based. But one day it dawned on me that the idea of constant stabilization was sidetracking me from using my cameras in the most effective ways. I was becoming dependent upon the camera to stabilize everything and, by extension, to make everything sharp, but I was so impressed with some cameras' abilities to work miracles at shutter speeds as low as 1/8th of second that it was becoming of game of seeing just how low we could put the limbo stick of exposure before camera movement started to manifest itself.
Of course none of this took into consideration the more important effects of subject motion. If you are photographing a person who is talking with some degree of animation; moving their hands, nodding their head and bouncing from one foot to the other then all the image stabilization your camera can muster won't fix the problem of blurry hands, blurry heads and blurry bodies that come from trying to capture life at too slow a shutter speed. An animated speaker needs, at a minimum, about 1/125th of a second exposure in order to give the camera a fighting chance of pulling off a perceptively sharp image. You're much better off is you head up to 1/250th of a second as your minimum shutter speed. Subject motion is generally a much more realistic determiner of quality with any animated subject. I'm sure of this because I've spent the last 32 years trying to figure out how to shoot theatrical dress rehearsals where one is dealing with a triangle of evils in the image making. You need a fast enough shutter to freeze, or at least minimize, motion but you'll need a higher ISO to get you that shutter speed because the lighting is fixed. If you add clicks to the ISO dial you'll get more noise. Sometimes it's possible to use a faster lens but the longer your focal length the less and less likely that you'll find as fast an aperture as you do on shorter lenses.
The third side of the triangle is light levels. In a shot that your are setting up and lighting you have the option of cranking up the power on your lights, but in the theater or in reportage you don't have the option to modify the light; you shoot with what you get.
I used to think that image stabilization was mandatory even in the 1/160th and 1/250th range of shutter speeds, I mean, why not have all the potential image quality magnifiers you can get? Right? But one evening, after a long and crushing week, I shot a show at my local theater under challenging lighting with the fairly fast Olympus 40-150mm f2.8 Pro lens. I had been shooting with a GH5 and the (best in the universe all in one lens) Olympus 12-100mm f4.0 Pro lens. The difference is that the shorter lens features really good I.S. while the longer lens doesn't have I.S. at all; it depends on the bodies to supply the support.
I forgot that in the moment and didn't have the I.S. engaged in the body. I blithely shot the whole evening without the glory and majesty of technology enhanced stabilization. When I got into the office the next day I started my usual routine of importing files and editing them. I was halfway through the edit and things were going well. I took a break at the behest of Studio Dog (you gotta play fetch at some point during the day or you might be a piss poor dog companion....) and when she did something super cute I grabbed the camera and blasted off a few frames. Then I look for the I.S. switch on the lens and BAM! in a moment of cold sweat awareness realized that it didn't exist. I flipped into the camera menu sure that I must have had the in-body stabilization engaged but HORRORS! no.
For the rest of the morning I kept reflexively grabbing frames from the edit and enlarging them to 1:1 on my 27 inch screen. I was certain my folly would become obvious. Equally certain that my client would gasp in disgust and toss the whole shoot back in my face...
Only it didn't work out that way. I'd hewed to good practices and kept the shutter speeds as high as I could without cresting the 1600 ISO mark. I mostly shot the evening before between 1/160th of a second and 1/320th of a second. The images were very, very sharp. Comparing them with production photos from a month earlier made me realize that, at the shutter speeds I'd chosen to freeze subject motion the presence or absence of image stabilization was largely inconsequential.
I logged that information away in my brain and let it ferment. And then I started taking more "chances" because after all, we'd been able to make perfectly good photographs all the time before the invention of this amazing technology. So, this last weekend I found myself shooting a bunch of stuff at an Amputee Coalition event with a Nikon D700 and a Nikon 24-120mm f4.0 VR lens (VR is Nikon's brand of stabilization. The VR stands for "vibration reduction").
I was shooting everything at f4.5 because the lens is sharp there and I like to drop backgrounds out of focus. I thought of it as a benefit that the lens also brought me really good image stabilization as well. But the combination of the f4.5 (for sharpness), the light levels, and the desire to keep ISO around 800 for the best looking available light files meant that I was shooting down in the 1/60th to 1/125th zone. I was getting blur from head movement and arm & hand motion. More than I wanted. I pulled a (non-stabilized) 50mm lens out of the bag and set it to f2.5 which gave me the ability to use nearly two more stops of shutter speed without changing my ISO. That meant shots at 1/250th or 1/320th of a second. I started getting more shots without subject blur and I got the added bonus of less in focus in the background.
Had I needed more depth of field at the higher shutter speeds (keeping the ISO the same) I guess I could have switched to a smaller format. Too bad I didn't pack a smaller format system...
When we are given new features we tend to let them become mandatory settings for everything and then, since we are only human, we get over confident that I.S. will save our bacon in a pinch. That a newer system will let us go lower and lower with shutter speeds. But too often we misjudge what the important parameters of a shot might be. If the camera makers put a new and improved "hammer" feature in our cameras then every shooting situation seems like a new and improved "nail" situation.
There really are no technical reasons I know of not to just leave I.S. on (unless you are putting your camera on a stable tripod) except for one that might affect users of "mini-battery" cameras like the first two generations of Sony A7 cameras or Fuji cameras. Image stabilization does consume battery power. As long as it's in use it's sucking down power like crazy.
On the flip side there is a benefit which doesn't get as much mention as the primary function of I.S. (reducing blur) and that is the presentation of a stabilized viewfinder. And when you get a stabilized view through the finder your autofocusing module is also getting a stabilized feed which, theoretically should make focusing easier for your camera.
The important thing I wanted to get across here is that image stabilization is not a magic bullet for everything. You still have to pay a lot of attention to subject motion. More so when light levels fall. Image stabilization is great to have but you still have to pay attention to the rest of the photographic equation. At least if you want sharp photos of moving objects....
I'm not particularly religious about which way I "must" have my I.S. I get that having it in-body means I get to apply the benefit of the feature to older lenses or lenses that may not have I.S. built in. But on a theoretical level I can make a convincing argument that having the I.S. custom designed and calibrated for individual lens designs (especially longer focal lengths) should be more effective. Think for a second about how far a sensor would have to be able to move to correct for camera motion with something like a 300mm lens. Eventually the sensor will run out of space in the camera to travel further. A long lens with built in stabilization can offer a greater range of correction when you get near the boundaries of what's possible --- at least in theory.
Ah, what the hell. Just remember to match shutter speed to subject movement and I bet everything will turn out well.
