Hi everybody,
I want to share an idea that solved two issues that annoyed me when using my A7R with Canon lenses via metabones adapter:
1. The first issue is the shutter shake with longer lenses at certain shutter speeds that has been described widely in several forums.
2. The second issue is a bit special and will probably only bother people who shoot architecture: although I use a geared head with very precise bubble levels and usually adjust very careful - verticals quite often were not perfectly vertical and I had to correct that in post. I figured out this could partially be my fault but partially also because there is some play between the adapter and the camera mount: you can rotate the camera a bit against the adapter that is mounted to the tripod. Not much, less than 1 degree, but you can see that in architectural images.
My idea was to couple adapter and camera so they can't rotate against each other any more. This coupling also dampens the shutter shake. As you can see in the comparison images (100% crops): the shutter shake at the criticals shutter speeds around 1/100th is reduced to nearly imperceptible. I ran three tests to be sure I do not cheat myself: it seems to work.
I do not have access to CNC machining, so I had to help myself with prefabricated stuff and a very provisional construction to try out my idea:
I started using a universal plate by Really Right Stuff (the B76). On top of one side of the plate I taped a small rectangular brass profile (12 x 5 mm, 70 mm long) that exactly fills the gap between the base plate and the camera. ATTENTION: it should NOT be thicker than the gap, or you will destroy the camera mount !!! I sanded off a few fractions of millimeters, now it's a bit less than 5mm thick and fits perfectly. I mount the adapter to the camera and after that I screw the base plate to the adapter foot. The plate has a ridge to prevent the adapter foot from twisting.
I know it looks a bit funny, but so far it seems to work. Would be nice if one of the specialized brands like RRS or Hejnar would offer something like that in one part - maybe even an L-Plate that extends far enough to support the camera too.
Marc
