I recently got a Rectimascop 48 2x and I'm having problems getting sharp images with my GH4. As a taking lens I tried a Nikkor 50mm 1.8, Nikkor 50mm 1.2, Nikkor 85mm 1.8 and a Helios 44 58mm 2.0. I saw several videos on youtube/vimeo using the GH4 with the Helios 58mm and the Rectimascop 48 and they seemed to be pretty sharp (sharper than my tries at least).
The Rectimascop is attached to the taking lens as close as possible by a filterclamp and I make sure it is rotated such that the image doesn't skew.
I can't seem to get a sharp image if I don't stop down to f8 or further on my taking lens. Trying to focus on a target wide open and stop down later, like some guides suggest, is impossible. Even at 2.8 I only manage to either get my focus plane slighty unsharp with round bokeh or only the horizontal or vertical plane sharp with a weird pointy 45° bokeh. (Focus distances I tried ranged from 10m to infinity)
I focus by focusing the taking lens first, trying to dial in the distance to the target. Then I adjust the anamorphot until I get a fairly round bokeh at the distance I want to focus. Now I carefully adjust the taking lens and the Rectimascop and vice versa until I can't get any sharper. It is only at f8 and smaller that I get a resonably sharp picture.
Now my question is: Am I expecting too much? Can I only use the Rectimascop stopped down to f8 and smaller if I want sharp pictures? Or maybe there is a problem with the anamorphot? (I thought that maybe the front and back lens are not 100% alligned, is that possible?) User error?
I would be glad for some help/advice. I'm fairly experienced with cameras and filming but an absolute newbie with anamorphotic lenses.