GH4 Sigma 18-35 + Metabones only stops down to f/11

refocusedmedia

refocusedmedia

Veteran
I recently got the Metabones Speed Booster "S" and the Sigma 18-35 f/1.8 lens (Canon mount). In my initial play-testing, I noticed I cannot stop down past f/11, even though the lens has a minimum aperture of f/16. The adapter was updated to the latest firmware before I mounted anything, if that matters.

Elsewhere, someone told me some third-party zooms have to be "registered" with the adapter. I've followed these instructions, but I heard no "click" and nothing seemed to change.

Also, someone told me that the extra stop of light at the wide end also means one less top of light at the narrow end. I wondered about that, but I can't seem to find anything definitive stating if that truly is the case or not.

Anyway, it's not the end of the world but it threw me off and I wondered if I was the only one who had seen this, or if there was a fix.

Thanks
 
Right. The lens has a minimum aperture of f16. The SB increases the entire aperture range by one stop. One stop up from f16 is f11.
 
mcbob said:
Right. The lens has a minimum aperture of f16. The SB increases the entire aperture range by one stop. One stop up from f16 is f11.
Click to expand...

Thats what I've come to realize, and it makes complete sense, just no one ever mentions the "loss" at the other end so I wasn't expecting it. Not a big deal.
 
Bear in mind that although the camera and Speed Booster report the effective aperture, the physical iris blades are still stopping down to their minimum aperture. You'll have to compensate with a stop higher ND. I have a full set of Tiffen IRND filters from 0.3 to 2.1 (7 stops) in my bag for video shooting, and I've definitely used the 2.1 more than once in bright sunshine in order to shoot at my desired aperture setting for the scene. If you're on a budget get one of the variable ND filters instead.

HTH

Cheers,

Paul :)
 
You must log in or register to reply here.
Back
Top