Why IS and VR Matter
© 2006 KenRockwell.com

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Percentage of Sharp Images vs. Shutter Speed.
(Photo examples follow)

INTRODUCTION

I'm addicted to Canon's IS (Image Stabilization) and Nikon's VR (Vibration Reduction). They help me get much sharper images with long lenses, and with all lenses in dim light.

IS and VR are so important to helping me get great shots I won't buy a lens or camera without it, given the choice.

As I'll show shortly, even a point-and-shoot with IS is sharper than an expensive DSLR camera without IS in some conditions.

VR vs. IS

VR and IS are the same. I'll use both terms interchangeably. Each maker uses their own acronyms.

Each stabilizes images from the jiggly effects of hand-holding. It helps replace a tripod for making sharp photos. IS and VR let me shoot in bad light and forget a tripod, except for the most formal night shots.

IS and VR work great for subjects that hold still, which is most of what I photograph. VR doesn't do anything for subjects that are moving, like sports and kids.

Some folks like to use VR and IS to help get better motion panning shots, in which case the VR stabilizes one direction while the other is blurred.

To reduce the effects of subject motion you still need to use faster lenses, more light, or a higher ISO.

OTHER MAKERS

Minolta (now Sony) make DSLRs which move the sensor to counteract camera movement. I have not tried them. An advantage is that they claim to work with all your lenses, since the VR is in the body, not each lens.

Beware the phrase "anti-shake." Most of the makers who use this term are cheating and merely boosting the ISO to get faster shutter speeds. You can set higher ISOs yourself. They usually do nothing to counteract camera motion as IS and VR do.

Panasonic and Leica makes cameras with real image stabilization, too. I haven't tried them.

HOW THEY WORK

I'll skip the details, but real IS and VR use motion sensors to detect motion while the photo is being exposed.

They then use various devices to shift the optical image (or move the image sensor) to counteract this motion in real time.

They ensure the image stays stable during exposure.

You can see them work through the viewfinder (Nikon and Canon SLRs) and on the LCD (Canon compacts).

THE GAMBLE and the GRAPH

Hand jiggling, also called tremor by doctors and vibration by Nikon, is random.

Make enough photos in any condition and some will be sharp and some will be blurry. The percentage depends on the conditions, shutter speed and focal length.

The graph shows how your percentage of sharp shots increases with shutter speed. At very long shutter speeds, like 30 seconds, you will almost never get sharp photos hand-held, regardless of having VR. It's never 0.00%. Shoot enough and you might get lucky and get a sharp one, even at really long speeds.

At fast speeds, like 1/1,000, you'll get sharp shots almost 100% of the time, again regardless of having VR or not. Again, almost 100% isn't 100%. Make enough shots at high speed and you may get an unsharp one.

This comes down to probability and statistics. There are mathematicians who explain this better. Because this is due to chance and random probability the results can vary each time.

This graph shows how makers come up with their "stops of improvement" claims, depending on how their system performs.

The exact shutter speeds and shape of the curves all depend on you, your surroundings and the focal length. The graph is hand-drawn to illustrate what VR does and doesn't do.

The old wives' tale about using at least 1/30 or at least 1/(focal length) comes from a general observation that for most people, you'll get about 50% sharp shots at that speed. That's the middle of the black "no VR" curve. Being a random function, faster speeds will give a larger percentage of sharp shots, and vice-versa.

TRICK: Since we're playing odds, I always stack things in my favor by using a camera's Continuous shutter mode and holding the shutter down to make several shots. I pick the sharpest later. As the shutter speeds get slower and the lenses get longer, I make more and more shots. For instance, if I'm under a condition that might give me sharp shots 10% of the time, I'll make 10 or 20 shots and pick the winner. This works!

Likewise, this is why you can get blur from camera movement even at 1/250 second with a normal lens. The odds are that every so often you'll get a loser. If it's critical, make a couple of shots to be sure.

WHERE VR SHINES

VR and IS give huge improvements in the sweet spot where the two curves separate. Shoot at about 1/2 - 1/15 of a second with normal lenses and you'll see the biggest night-and-day difference. Shoot faster and both are sharp, shoot slower and even IS gets blurry.

EXAMPLES

Guide image from which crops are taken.

Here's my 10MP D200 with my 18-135mm non-VR lens compared to my 6MP D70 with 18-200mm VR lens. I show the D70 at 100% magnification, and the D200 at a little less so they match.

Roll your mouse over the image to see the other image for comparison.

Roll your mouse over this to compare my D200 without VR lens to my D70 with VR lens.

Now can you see one of the many reasons I suggest a less expensive body and better lens? Remember that lenses are useful for about 5 - 10 years, while digital bodies go obsolete each year. The less expensive D70 / 18-200mm VR combo is much better hand-held at slow speeds than the much higher resolution D200 without a VR lens.

Of course these are shot at 1/4 second at 28mm where VR makes a big difference. At much higher speeds it doesn't make a difference, but it does make a difference, even in direct sunlight, at 135mm.

How about this. Roll your mouse over to see the difference:

Roll your mouse over to compare my D200 without a VR lens to my Canon SD700 pocket camera with IS.

IS and VR are the keys to sharp shots at the exposure times typical of indoor and available light shooting. In the real world, even a tiny point-and-shoot with IS can run rings around a 10 MP DSLR without VR when the light gets dim and you don't have a tripod.

For each shot I made six shots. With VR or IS, five or six shots were this sharp. Without VR or IS, five or six were this blurry. I made that many shots to ensure what I show is representative. If you make enough shots you can eventually get a blurry IS shot and clear shot without.

Sorry the sizes and exposures don't match perfectly. Pocket cameras only zoom in steps so I got it as close as I could without resizing images as I had to for the DSLRs. The SD700 is a 6MP camera. Oddly the pocket camera looks even sharper than the D70: the pocket camera uses more default sharpening internally and wound up having more contrast after I quickly matched the levels.

RECOMMENDATIONS

IS and VR are critical to sharp hand-held images up to about 1/60 second with normal lenses, and up to about 1/500 with telephoto lenses.

At exposures of more than a few seconds IS and VR are no help - you need a tripod or rest your camera on something solid.

Personally my best shots are grab shots made outdoors in fading light. Therefore I LOVE VR and IS!

PLUG

If you find this as helpful as a book you might have had to buy or a workshop you may have had to take, feel free to help me write more with a donation.

Thanks for reading!

Ken