I got a Sigma EX 24-70mm DG HSM lens off ebay for cheap, description said it hangs at 50mm. Still worth a try I thought, since I found this video of a similar fix. Unfortunately, the lens in the video is a different one, which I realised after unscrewing the top like in the video, and then already had lifted off the top lens 😉
Beware, I never disassembled a SLR lens, but having soldered PCI slots into notebooks and disassembled and fixed several smartphones, I’m not the kind of guy who is frightened by something like this.
Be careful though, I botched one of the screws, although I even got me some J.I.S. screwdrivers.
The first problem was easily found, a slide guide seemed to have come off somewhere and got in the zoom mechanic. After taking it out, the zoom worked again in the full range. However, it was quite stiff after reassembling the lens, so I thought I’d further investigate and took it apart. Clearly, the guide roll should be somewhere in there, and since it wasn’t broken, there should have the screw that held it fallen off and be somewhere inside. Couldn’t find it though 😉
