Bum Ki Cho a filmmaker and DVXUser member introduced folks to his B4 to Canon FD adapter that he helped get made from a manufacturer in Korea. I was fortunate enough to be able to purchase a couple mounts from him before he left to Korea and recently did some testing with it. With this new B4 mount you can attach it to any Canon FD to m4/3 adapter and have yet another way to make the m4/3 system shine.
The B4 to Canon FD adapter mount is well machined and thinner than expected. When I place it on my Canon FD mount it adds only an additional 13.5mm to the front of the FD mount. So it’s not that big of an add-on to the FD mount which is great. When you attach the B4 lens to both pieces it really feels like one complete piece. Strong and sturdy.
When I got the mount in the mail it was about 6pm so there was very little time for me to shoot. I jumped on the trolley and headed for Chinatown. Today’s test was with the beautiful Canon J8x6B 6-48mm 1:1.7 B4 lens that I purchased from a DVXUser member in Alaska. This is not a cheap lens but I took a gamble and I have to say it’s worth it. This is so far one of the best wide angle zoom lenses that I’ve put on the GH1. You must use the Canon 2x doubler in order to get a full image, engaging the setting on the widest angle would make the lens 12mm making its 35mm equivalent FOV of 24mm. My first words were “WOW!” I have a lot of legacy lenses and it was such a surprise to see a lens still hold its sharpness with the doubler. Overall, there seemed to be very nice sharpness from the center to the edge of the frame with very little vignetting.
One caveat is that I was shooting with no ND filters so I was stopped down to about f/5.6 so I’d still like to check over all sharpness wide open on a future test. As you go up to the higher focal range, it does soften up and darken slightly depending on lighting conditions. Shots are still very usable despite the slight softness there.
Overall, this is one of the best zoom lenses I’ve put on the GH1. It’s fast and sharp and perfect for run and gun situations. With other legacy zooms you must use the digital zoom on the camera which degrades the image. Using the 2x doubler allows you to shoot full resolution. Because this lens is pretty sharp it still holds even with the 2x engaged on the lens. There needs to be more tests done obviously wide open and with NDs as well as to test the mount to see how well one can achieve infinity focus.
Since many of us already have FD mounts for our GH1 this B4 to FD addition was a good price point to jump on the wagon and I hope that Bum Ki’s manufacturer in Korea can make more of these available. In the mean time, I hope that more folks can shoot with B4 lenses. This is so great to bring ENG lenses to the GH1. Many thanks to Bum Ki Cho for making this possible.
Here is some footage shot in University City and Center City Philadelphia with the main goal of doing a general test to check edge to edge sharpness, vigenetting on the wides, and contrast for both tight and wide shots.
You will notice that on the opening footage of Calvary Church you can still pick out the sharpness of the right street sign (maybe not in the H.264 file but in the Prores transcoded file it is clear.) The 48th street sign is a little less sharp on the wide shot. Overall, pretty impressed with the overall edge to edge sharpness for using the 2x doubler on this lens.
Also, on all the wides you’ll see the matte box on the right edge of the frame when removed the picture is clear from edge to edge. It was a little unusual that I did not see it on the left side and only the right side.
One not so great thing is that the lens flares are right dead center and you’ll see that in the opening shot.
In the Center City footage the Reading Terminal sign is nice and sharp and even the outside shots under the over hang where I was wide open was fairly sharp on the neon signs wide open. When you are at the farthest end of the zoom there’s softness there and the image does darken but not as much as I’d expect it to be.
The shot with the little boy near the trolley and public art space was wide open. There is very little contrast and you sort of enter into a slightly “dreamy” look at times wide open. Again, No ND filters so your seeing footage straight from the lens.