In preliminary testing on the T2i I found the MIR 1B to be sharp, especially from f4, with low distortion and excellent color rendition. Shadow detail is excellent. The lens is prone to flare so use a lens hood at all times. Chromatic aberration is minimal. Focusing is smooth and precise. The aperture is almost circular and stepless, which is nice for shooting video.

*Note: The Mir 1B 37mm has a ring on its mount which extends 2mm too far into the 6D camera body when the lens is focused past 15 feet. The ring will make contact with the camera's mirror. There is a work around for this problem which doesn't require modification of the lens. Shoot in live view mode. When shooting in live view mode the mirror is locked into the up position. It is very important that you follow these steps.
1. Turn camera on w/out the lens attached.
2. Turn off power saver mode and/or the auto off option.
3. Put camera in live view mode.
4. Attach lens.
5. Shoot in live view mode only.
6. Do not turn off live view or the camera until you dismount the lens.
7. Dismount the lens.
8. Turn the camera off.​