How do I change to manual focus on sigma 10-20mm with Nikon d3100¿

[Dale_tem]

I was taking some night time shots with minimal light. The AF was unable to focus and I normally change to manual, but on this lens there is no switch, you can just refocus, but how do I tell the d3100 this? It won't take a photo as it cannot see if it is in focus or not.

 

[freecom2]

The switch is between the zoom ring and lens mount on the pictures I can see?

 

[Dale_tem]

There is no switch on mine, but I am now doubting this, will double check.

 

[freecom2]

I've found another picture of an example that doesn't appear to have the switch, it might be a later addition: http://farm1.static.flickr.com/227/500835047_cbfa76e357.jpg

Either way, in the myriad of options on the rear display there should be one that controls focus modes. It might be in AF-A, AF-S or AF-C, but you want MF (manual focus).

 

[Dale_tem]

Doh! Didn't think about that screen (so bleeding obvious it is untrue), I was looking for a manual focus/autofocus on the other menu.

Thanks

 

[ohara]

Whoa that's weird...my Sigma 10-20mm has an AF switch :/

 

[odd jim]

For some reason it's only the Canon mount that has the switch.

Neither the Nikon or Sony versions have one. It's controlled via the camera only on those mounts. Not sure why.

 

[Farno]

Yup, just flip the switch on the camera body.

 

[freecom2]

Yup, just flip the switch on the camera body.

Not all bodies (like the D3100) have a physical switch for choosing AF.

 

[odd jim]

Not all bodies (like the D3100) have a physical switch for choosing AF.

Indeed, they will be menu jobs!