I never did any kind of testing of my camera equipment before but sitting here this evening I said I’d conduct a quick & simple test (it was very quick & very simple). The reason for doing so was born out of intrigue having recently had reason to debate the effectiveness of on/in-lens image stabilisation, that glorious feature that helps you take handheld shots anywhere from 2-4 stops slower than with image stabilization off, depending on its effectiveness. So I pulled out my camera & image stabilised zoom & got to work.
Paragon Of Optics
I’ve had my Sigma 18-200mm f/3.5-6.3 zoom, that paragon of optics, for some 2 years now but I never really thought too much about its OS feature (OS, standing for Optical Stabilisation, is Sigma’s variant of the technology). Up until now I had just assumed it worked. After all, the lens manufactures wax lyrical about the benefits of the feature & stabilised versions of lenses are a lot more expensive than their non-stabilised brethren. I don’t use the lens all that often & even when I do I work within its limitations, rarely using it in anything other than bright light when the need for image stabilisation is reduced. So I’ve never had reason to test it myself, until now.
The lens was mounted on my EOS 60D which was set to P mode with mostly auto settings (ISO & white balance). Centre point AF focusing was selected & the lens extended to 200mm. Given the low-light conditions the camera shot at iso3200 with the lens at aperture f/6.3, its widest possible aperture value at that focal length. This is the condition (low light) & zone (above f/5.6) where these cheap, all-in-one walkaround lenses may suffer with focusing difficulty, although on this occasion the camera locked focus pretty quickly. This was to be expected given that both the camera & subject were stationary relative to each other & I was selecting the AF point, not leaving it up to the camera, something you really should be doing if using this particular lens at this focal length in low light which, let’s be honest, is something you shouldn’t be doing anyway – those limitations I spoke of.
Anyway, I digress. The test, such was its complexity, saw me taking 10 hand-held pictures in low light – 5 with image stabilisation disabled & 5 with it enabled. I refocused each & every time & tried my damnedest to feather the shutter button as delicately as possible – & capture the image as quickly as possible – after focus was signaled as having been reached. Shown below are the best 2 image captures, image 1 the best of the non-OS-enabled captures & image 2 the best of the OS-enabled captures.
From this simple test alone it’s pretty obvious that this whole image stabilisation lark works, even with a budget-esque Sigma zoom. And it’s pretty conclusive when one considers that the worst of the OS-enabled images I captured was still way better than the best of the non-OS-enabled images I captured.
So there we have it. My first camera equipment test, unequivocally proving what everyone already knew.
Right, I’m off to find something else to test.
Update: November 14th, 2011
I found this video courtesy of Camera Technica which shows the IS operation of a Canon 18-55mm kit lens. There’s a good article to accompany it too. The bottom line is they agree with me, that IS works! So that’s good to know.
– Ken Rockwell – Why IS & VR Matter