sigma 90mm f2.8 macro

ken wrote:

hi need help with a sigma 90mm f2.8 macro lens on a 7d,the auto focus works but the aperture doesnt seem to work it is always f2.8 and if i set the camera to manual and try to adjust it the camera gives me a error code 01

Older Sigmas have an electrical problem, where things go wrong the moment the lens tries to close the aperture. The Canon DSLRs got to be more strict about the signals, and the older Sigmas ceased to work properly.

At the beginning of the problem (around 2003 I believe), Sigma offered to replace the electronics boards of lenses. Now they are not able to anymore (no spare parts).

So, there are only three things you can do:

* Use the lens as 90mm portrait lens, wide open. Will give nice subject separation.

* Close the lens to an aperture you can live with, on a film body. Something like f5.6 or f8 or f11, depending on which DOF you find to be the best compromise for your uses. Close the aperture with the button on the camera body, and while keeping it closed, take the lens off the camera. Tape off all contacts of the lens, and use it as manual focus macro lens with fixed aperture. You can of course set another aperture at some point, on the film body.

* Look for another macro lens. My suggestions for those: Tokina 35mm f2.8 DX Macro, Tamron 60mm f2 Di II macro, Sigma 70mm f2.8 EX DG macro, Tamron 90mm f2.8 Di  macro/Di VC macro, Canon 100mm f2.8 USM macro/L IS USM macro, Sigma 105mm f2.8 EX DG OS HSM macro, Sigma 150mm f2.8 OS macro, Sigma 180mm f2.8 OS macro, Canon 180mm f3.5 L USM macro, Tamron 180mm f3.5 Di macro. Pick your favorite focal length/field of view from those.