Sony A7II, Metabones IV, Canon EF 300mm F4.0 IS L and Sigma Teleconverters

When I first got the Metabones IV adapter for my Sony A7 system I was using an A7R and the intent was to use my Canon TSE lenses. I gave the 300mm a try and found that the adapter did not communicate aperture settings to the camera so it was always F4.0. I decided I’d sell it along with my other Canon lenses that I wasn’t planning to use with the Sony via the Metabones adapter.

A couple of weeks ago I saw something in a forum post about Metabones firmware and went to the site to see if there was an update for my version. There was (V.41) so I downloaded into the adapter and did a quick test with the 300. The lens now transmitted aperture data to the camera via the adapter and I could change the aperture. Now the lens was useful.

I have two Sigma teleconverters, the latest version, originally purchased to use with a Sigma 120-300 F2.8. I sold that lens when I sold my Canon Cameras but not the adapters. So, I decided to test them as well. They worked with the lens and adapter to communicate aperture and support aperture adjustment via the camera.

So, now it was time to do a test to see if the combination of Sony A7II, Metabones adapter, Canon 300mm L lens and the Sigma adapter could product acceptable results.

I did some quick hand held testing and was impressed but a forum post about shooting the moon with a long tele lens on a tripod got me to do a more comprehensive test. Camera, lens combination was mounted on my heaviest tripod which has a large ball head. Both from Calumet Photo before its demise. I mounted the lens to the tripod via its ring and let the camera and Metabones adapter counter balance the lens. The mounting arrangement also made changing the Sigma teleconverters easier as well.

All the images are camera generated JPGs. The cropped images are as close to 100% as I could get by cropping them in the Lightroom develop module. They are from the center of the frame. I know some people want to see edge to edge 100% crops to see about corner sharpness. I find that the edge of an image is generally less important so I rarely have a need to ensure sharpness there. Especially at widest aperture. If the edges are important I’ll be stopping down the lens to its optimum aperture. Even so, when I looked at the images in Lightroom at 100% I was rewarded with reasonably sharp edges wide open. Including the teleconverter test images.

There is no additional sharpening applied in Lightroom or when exporting.

Here are the results:


300mm 100% crop at center of frame


300mm full frame


420mm with Sigma 1.4 converter, F5.6 100% crop


420mm full frame, with Sigma 1.4 teleconverter.


600mm, F8.0, 100% crop with Sigma 2.0 Teleconverter

300mm F4.0 full frame OOC JPG

600mm F8.0 full frame with Sigma 2.0 Teleconverter


Full frame 600mm shot. Manual focus on the rolled leaf. F8.0 with 2.0 teleconverter. 400 ISO and 1/80 shutter speed. No additional weighting on tripod to dampen shutter. Shot as a 3 frame bracket. The white streaks are rain drops. This attests to the slow shutter speed.


100% crop, center of frame. Its evident that there is some camera shake. But still a reasonable result given the camera settings. The plant is about 30 feet from the camera position so any camera movement is amplified by the short focal distance.

I am favorably impressed with these results. I think I’ve found an acceptable combination for long lens shooting.

I ordered a gimbal head to mount on a monopod which should help to steady the combination. I got the idea from a review Michael Reichmann did on his Luminous Landscape site.