I have a simple non-chipped adaptor for 40 Euro. Some experiences:
- Using manual is a pain because the exposure simulation doesn't work. With Av mode everything is o.k.
- Manual focus is easy with 5x or 10x magnification but not for moving subjects. Just focusing via the excellent display is possible (by focusing back and forth and minimizing the intervals).
- Quality of the old lenses is mediocre compared to the new lenses I use on the 600D (3.5 50 macro, 4.0 17, 2.5 135, 4.0 200). Just the 1.4 50 mm chrome ring is an exception. I am really impressed by the clarity of the images. See the example below. The center strip (2nd image in my post) is a 100% view:
Yes, I totally agreed that manual focusing is a pain especially using a relatively large and out of balance vintage lens on a tiny camera body. Using 5X or 10X magnification is difficulty when doing handheld shooting. It may work on tripod which provide some stability.
I have the following DIY project to share.
1. I installed the Magic lantern on the M and made use of the focus peak or focus zoom which is easier to check the in-focus area than the in-camera magnification feature.
2. I attached the LCD Viewfinder V3 to the M (which I bought previously for my X5 - never used actually) after modifying the base by drilling a hole to match the mounting position of the M, stability is improved. Some magnification of the V3 helps to view the image on the LCD clearly. The viewfinder is detachable and won't block the LCD for touch screen functionality.
3. I don't have to worry about reflection of the strong ambient light on the LCD when shooting in very bright environment.
4. It didn't cost me a penny in this project - I used the V3 already available. I just spent 5 minutes to find the correct position of the mounting hole and drill it on the base and that's it.