Apparently DOF dosent work with all lenses?

[ShutteringFocus]

My sigma 28-135 5.6 Aspherical lens wont stop down when I push the DOF button on my D30.

It works with my sigma 70-200 2.8 EX.

Is this normal?

[Olegis]

Did you try the lens on another camera ? As far as I know - all EOS-mount lenses should stop down when the DOF preview button is pressed.

[ScottE]

Some older Sigma lenses will not work with newer Canon cameras. At best they will just not stop down. At worst they will freeze up the camera so that you have to turn it off and remove and reinsurt the battery to free it up.

Often you can send the lens back to the Sigma distributor and they will replace the computer chip that operates the lens. That will make it compatable for all current Canon cameras, but makes no guarantees for future camera models.

Unfortunately Sigma cannot support all discontinued models of lenses so it is not possible to get some lenses re-chipped for the latest cameras.

Sigma is one of the largest lens manufacturers in the world and there seems to be some kind of competition going between Sigma and Canon. Sigma engineers their lenses to work with all current Canon cameras. Canon then activates some hidden feature in new camera models so the Sigma lenses don't work, but all Canon EF lenses will. I believe that Sigma EX lenses with HSM motors are the least susceptable to these games, although the 105 EX macro has been a victim a couple of times.

For example I have a Sigma 105 macro lens that I bought many years ago and it worked very well. When I acquired an EOS 3 film camera the lens would no longer stop down when taking pictures. I sent it in and had it re-chipped. I worked fine with my subsequent cameras, including the D60 DSLR. I now have a 20D and the Sigma 105 causes the camera to freeze up as soon as the shutter is pressed. I am still waiting for word from the Canadian Sigma distributor about whether I can send it in to be re-chipped again. (They do a very good job and have fast service. The lens comes back looking like it is brand new. This is probably the cheapest way to get a professional cleaning and reconditioning.)

[dhbailey]

Are you sure you've set things so that the aperture should be smaller than you are seeing? I was fooled a bit trying that with a slower lens I have, where I was shooting TV and it seemed that no matter what shutter setting I used, nothing happened with DOF button. But then I realized that the lighting situation was forcing the lens as open as it could go, so of course nothing would change when I pushed the DOF button.

When I changed light sources and could actually stop the lens down, it worked just fine.

[ShutteringFocus]

Yes, I cranked the F-stop to f/16 but still nothing. It doesnt freeze the camera...it just wont do anything.

However, I have had the camera freeze before when using this lens with the on-camera flash.

It's not the world's greatest lens it only cost about $110 USD. But still, the whole freezing thing is kinda anoying.

[Jesper]

Sounds like a lens compatibility problem.

Only Canon EF lenses (and EF-S on the bodies on which they physically fit) are guaranteed to work 100% on Canon EOS cameras.

The details of the EF mount (the electronic interface between the lens and the camera) are Canon's secret and they are not licensing it out to any third party.

Other companies such as Sigma, Tamrom etc. that make EOS-compatible lenses have to do this by reverse engineering the EF mount - they don't have the official specifications, so there is no guarantee that their lenses conform exactly to the interface. That means you shouldn't be too surprised if some functions don't work as they should....