Monday, April 27th 2009
When I got my Canon EOS 30D three years ago I decided to get the Sigma 17-70mm lens instead of the standard Canon EF-S 18-55mm kit lens.
On the whole the lens has worked very well, but recently I’ve discovered some odd behaviour from it.
Firstly, I noticed the other evening that it
hunted endlessly for focus without finding it, even though I was aiming at contrast edges which I normally think it would find. Admittedly light was perhaps a little dim, but certainly nowhere near dark.
I’m still not sure if this is a new issue or if the lens has behaved like this all the time. To some degree I know it has, but the hunting I saw now felt worse than anything I’ve seen previously.
The second issue I’ve had is this: When using the lens together with my 420EX flash the flash zoom head will keep jumping between different (incorrect) zoom settings. I suspect this is because of the lens sending incorrect focal length data to the camera.
Now I’m not 100% sure this is the lenses fault since I haven’t tried to reproduce the behaviour with another flash. The weird thing is that the focal lengths written to the Exif data in the photos seem correct.
Anyone else who has seen these issues with this lens?