Sigma 120-300 F2.8 with Tele ??

So I borrowed a Sig 120-300 F2.8 to try out. Love it and bought one.
When I put on my Kenko 1.4 teleconverter. the max App was F5.6
I new I would loose 1 stop of light so I expected it to drop to F4
Is this normal or am I missing something??
Thanks
Cheers SteveP

Tried it with another converter?

No I only have the one.

Also I have not tried it on the lens I bought yet but I will tonight.

OK so the camera must think it is a 2x tele when mounted to this lens because it shows as a 240-600 in the meta data. Strange.

Has anyone used a 1.4x teleconverter with this lens and managed to set at F4?

Try the teleconverter on another lens. If it also shows as a 2x then the teleconverter needs to be fixed.

On a side note, the difference between a 1.4x and 2x is the 1.4x shorts all 3 extra contacts while the 2x leaves the middle one open. It could just need a cleaning.

I use that exact combination and the combination reports to the camera correctly.

NOTE You must put the teleconverter on the lens and then mount the combination on the camera. Do not add the teleconverter to the camera and then mount the lens -- you will get errors.

I also use a Sigma 2x teleconverter with the 120-300 and it also reports, and works, properly -- f/5.6 and auto-focus etc.

Thanks that did the trick I have to put the tele on the lens then to the camera. I was doing it the other way around.

Cheers

I have never had any problems attaching teleconverters to camera & lens in any order.
Is that peculular to Kenko or Sigma?

Tapeman wrote in post #10173986
I have never had any problems attaching teleconverters to camera & lens in any order.
Is that peculular to Kenko or Sigma?

Me either. That's odd.

I do not know whether it appplies to all TCs, but it is in the instructions that came with both my Sigma TCs.

I believe it's an oddity with Sigma lenses. My Sigma 150mm acts strange when mounted in the "wrong" order (but in my case it thinks the TC isn't even there).