New 70d with 18-135 is stm lens. How to tell if image stabilization is working.

[bruce_bourton]

I've never had an IS lens. How can I tell positively that the IS is working? Thanks!

[Wouter Willemse]

<p>Shoot multiple photos hand-held at a slow speed (which would be hard to hand-hold, like 1/15th of a second at focal length of 50mm or more), with IS switched on and off. Compare the photos side by side, and what percentage is sharp or reasonably sharp. The difference should be apparent enough, the IS should yield you a much better percentage of sharp photos.</p>

[phule]

<p>Generally, I can also see it working through the viewfinder. Zoom to 135mm and handhold the camera with the shutter button half-pressed. If your subject is closer (ie not at infinity) you should see a difference in stability between IS off and IS on.</p>

[JosvanEekelen]

You should be able to see IS working through the viewfinder, especially at longer focal lengths. With IS the image is more

stable/less shaky than without.

[paddler4]

<p>I haven't ever tried an 18-135, but on some Canon lenses, you can hear the IS. Put the lens near your ear and half press the shutter, first with IS off and then with IS on. However, while this is quite loud with some lenses, it is quiet with others.</p>

<p>If you can't here it, I find it much easier to test as Wouter suggests, as I actually rarely notice in the viewfinder. However, I wouldn't do this at 50mm. You will see the biggest effects at the longest focal length. Rack the lens all the way out to 135mm. I would start with shots taken at 1/50, which should be within the range of what IS can handle at that length on your camera body, if you are holding it reasonably firmly. (The old rule of thumb, adjusted for your sensor size, is that it's hard to handhold a shot without IS at a shutter speed slower than 1/(FL*1.6). If your lens has 3-stop IS, that would take you down to roughly 1/25.0 I'd take 3 or 4 identical shots with IS off and then 3 or 4 with IS on. The difference should be quite obvious.</p>

<p>I've never encountered a new Canon lens with IS that didn't work, so I'd be surprised if yours doesn't.</p>