Vibration Reduction / Image Stabilization

No VR versus VR

Originally uploaded by Tukay Canuck

If you’re shopping for a lens, you may want to consider vibration reduction (on Nikons) or image stabilization (on Canons). These are marketed as “VR” and “IS” on the lens model name. Other brands have this technology too, and may have different marketing terms.

Image stabilization is a technology that stabilizes the lens even if your hand is shaking (your hand shakes – trust me). This allows you to shoot at slower shutter speeds and still get sharper images.

As a rule of thumb, you should shoot at 1/ (without using image stabilization). So if you are shooting with a 50mm lens, you shouldn’t shoot any slower than 1/50 of a second. If you are shooting with a 200mm lens, you shouldn’t shoot any slower than 1/200 of a second.

This is a rule of thumb, but you may be able to hold your camera more sturdier than the average person, and may be able to operate at slower shutter speeds.

Without image stabilization, if you are shooting at slower speeds than you can hold and keep the camera stable, then you will need to lower your f-stop (increase the aperture size), or boost your ISO.

Lowering the f-stop is a good option, as this will allow you to use a faster shutter speed. But if you are at your widest aperture (in this example, I’m at f2.8, which is as wide as this lens goes), then you are stuck.

Boosting the ISO is an option; this will also allow you to use a faster shutter speed while keeping the same f-stop. Boosting the ISO however introduces noise into the picture, and this may be undesirable. The more you have to boost your ISO to get the optimal shutter speed, the more noise you get. If it’s very low light, you may get a lot of noise due to a high ISO.

Vibration reduction/image stabilization introduces a new option – you can shoot at a slower shutter speed while keeping your f-stop the same and without having to increase your ISO as much (or not have to increase it at all).

In the example provided, I shot the freezer at f2.8, 70mm at 1/3 of a second, at ISO 200. Using my rule of thumb, I would need to quicken my shutter to 1/70s to get a sharp picture. Since I’m at the lowest f-stop number (2.8) that my lens will allow, I would have to increase my ISO to get 1/70, and the picture would get noisier (if I didn’t have VR).

In the second image, I have VR enabled. Note that even though I am shooting much slower than I should be able to steadily hold, the picture still looks reasonably sharp.

This is the great value from VR.

(Note: anther option in addition to boosting the ISO or lowering the f-stop is to mount your camera on a tripod. This is sometimes a good option, but a tripod is not always convenient, and sometimes not allowed.)

Light Meters

Today’s DSLR cameras have magnificent light metering technology. There are still situations where you will want to use a separate light meter. The main situation is where you are using studio flash lighting. If you set your camera to anything other than Manual mode, the camera will meter the lighting before the flashes fire, and that will result in an overexposed image.

When I first got my light meter, I didn’t understand why my light meter let you dial in the shutter speed I was going to use (which would then give you the aperture f-stop number after taking a light reading), but it wouldn’t let you input the f-stop and give you a shutter speed setting. After buying my studio lighting I then understood: when measuring studio lighting, you always know what shutter speed you are using based on the speed of your flashes. If your flashes fire at 1/200 of a second, you are going to set your camera to 1/200 of a second, and thus you need the light meter to tell you what f-stop to use. If you set your camera to a faster shutter speed, you may be too fast for the flash sync to occur. If you set it to a longer exposure, well, your studio flash (for example) is only firing at 1/200 of a second, so any longer won’t contribute to your exposure.

Having said all that, a light meter will give you a suggestion of f-stop based on what shutter speed (and ISO) you tell it you are going to use. It will give you that reading to provide you with an average (like the 18% gray) image. If you don’t want 18% gray, then you are going to tweak the numbers.

I find that trial and error with the camera is often faster than taking a light reading, and then tweaking (trial and error) to get the right lighting for the shot. Modern DSLRs have histograms, allowing you quickly see how much light is in your shot, and allowing you to quickly adjust if it’s too much or too little.

Since light meters can cost as much as an entry-level DSLR, my advice is not to bother with a light meter, or try to find a used one to see if you like it. You may find that the trial and error method is just as effective, and much cheaper!

(If you didn’t understand this post, don’t worry. Go back and read my post on Aperture and Shutter Speed. Then come back and re-read this).