Help Please

[brassoiler]

I have been using a Nikon d7200 camera with a sigma 150-600mm F5-6 DG OS HSM lens with a Sigma Tele converter TC-1401

I have just been trying to take a picture of a cloud formation in the distance and the lens wont focus automatically and the distance meter goes down from infinity to 2.8m
When I then change the subject matter of the picture I have to set the distance ring to infinity before the lens will focus automatically
the camera and the lens are set in AF mode but I'm wondering if I've missing something setting when I set the camera up with the lens

I can focus a cloud formation manually so I was wondering why it wont focus automatically

Any help will be very much appreciated

 

[Kodiak Qc]

•

Graham!

AF system acquire quickly and surely focus when it is
targeted at a subject with enough contrast. No contrast
means no focus acquisition… manual is the solution.

 

[brassoiler]

•

Graham!

AF system acquire quickly and surely focus when it is
targeted at a subject with enough contrast. No contrast
means no focus acquisition… manual is the solution.

Thank you for your help just thought I was doing something wrong

 

[HoppyUK]

I have been using a Nikon d7200 camera with a sigma 150-600mm F5-6 DG OS HSM lens with a Sigma Tele converter TC-1401

I have just been trying to take a picture of a cloud formation in the distance and the lens wont focus automatically and the distance meter goes down from infinity to 2.8m
When I then change the subject matter of the picture I have to set the distance ring to infinity before the lens will focus automatically
the camera and the lens are set in AF mode but I'm wondering if I've missing something setting when I set the camera up with the lens

I can focus a cloud formation manually so I was wondering why it wont focus automatically

Any help will be very much appreciated

As Kodiak says. The camera will struggle to focus on a cloud, but if a plane flies past it will lock on immediately.

The other thing is, all telephotos when focused close will have the far distance so out of focus that the system doesn't know which way to go, so you have to help it along with a tweak of the manual focusing ring. There are focus range limiters on the AF switch to stop this happening. AF will be more hesitant with the telecon attached.

 

[brassoiler]

As Kodiak says. The camera will struggle to focus on a cloud, but if a plane flies past it will lock on immediately.

The other thing is, all telephotos when focused close will have the far distance so out of focus that the system doesn't know which way to go, so you have to help it along with a tweak of the manual focusing ring. There are focus range limiters on the AF switch to stop this happening. AF will be more hesitant with the telecon attached.

Thank you