How Slow Can YOU Go? A Simple Test To Check Your PSSI (Personal Stabilized Speed Index)

When it comes to long lenses and related gear, a new age has dawned. Wildlife, sports, and even landscape photographers can now enjoy the convenience of stabilized lenses to shoot handheld with longer lenses at slower shutter speeds. The result is sharper images overall, especially in low-light situations. Another advantage is that you can easily add extension tubes, tele-converters, and the like to increase the effective focal length or get closer to your subject. You'll find that using a stabilized lens with these add-ons can really make a difference in your shots.

On the left is the Nikon D2X with their 70-200mm VR lens attached. To the right is the 200-400mm VR. The US Air Force target is shown as the test bed for the entire program; a flat mounted newspaper will do as well.

Many "digitally-dedicated" lenses benefit from a stabilization function, due to the "multiplication factor" of the lens/sensor. For example, when I use my Nikon D2X with the 70-200mm VR (Vibration Reduction) at its longest setting complete with the 1.5x factor, it becomes an effective 300mm lens. If I add a 1.4x converter, that jumps me up to 420mm with one stop less of light hitting the sensor. Add the 2x converter, I drop one more stop to f/5.6, but I'm looking at a compact 600mm lens! Work handheld at that focal length and the benefits of VR become obvious. Stabilization also comes in handy when using close-up attachments, especially on long lenses, or for any macro shooting work. Think of using a 70-200mm zoom that can focus as close as 20" from the subject and you get the picture.

The claim for various stabilized lenses is that they can get you three, sometimes four, stops of additional speed for handheld shooting. Typically you'll use this to pick up shutter speed for handheld shooting. For example, say you are shooting a long lens and the light, ISO setting, and aperture you need only yields 1/60 sec. Pre-stabilization you'd be having some difficulty and would have to boost ISO or give up some depth of field, if possible. Those three stops could be used to shoot at 1/60 sec and results would be equivalent to 1/500 sec.

Stabilization Benefit
This Blue Heron was caught at 1/750 sec at f/4 using the 200-400mm VR lens handheld.
Photos © 2008, Stan Trzoniec, All Rights Reserved

But like everything else in photography, how you work, your steadiness, and the gear you choose might alter these optimum results. That's why I devised this test you can use with your camera, your lens, and the way you hand hold your camera. I call this test the PSSI, or "Personal Stabilized Speed Index." It is a subjective test, but that's what it's supposed to deliver, a personal range of effective stop pickups that works for you.

I decided to use a Nikon 70-200mm VR and a 200-400mm VR for the examples here. I tested with and without extenders at lower than average shutter speeds. As I tested it became obvious that the overall dimensions and the weight of the lens can affect results. You certainly have to adjust to a heavier and longer lens, here the 200-400mm. Good technique--bracing the lens against your face, tucking your arms into your body--aids sharpness regardless of whether a lens is in Stabilized mode or not.

Stabilized lenses have their own "menu." From the top, you have the manual/automatic manual switch, followed by the focus limiter, VR on/off switch, and the Normal/Active mode. Active can be a great aid when working from a moving vehicle.
Nikon 70-200mm VR lens.
Nikon 200-400mm VR lens.
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