And I just uploaded a new video using the same adapter, but with the Ensinor 500mm f/8 mirror lens
Canon 600D / T3i - Ensinor 500mm f/8 - Mirror Lens Video Test - M42 to EOS - HD - YouTube
I short sample video showing my M42 lens which is a Chinon 200mm f/3.5 with the M42 to EOS adapter which allows me to use it on my Canon 600D DSLR camera.
A very nice lens, and very cheap on ebay at the moment, I definitely recommend adding one to your lens bag.
It has a long focus pull of over 180 degrees, but the ring is quite difficult to turn. The bokeh looks quite nice though.
I was going to say it looked like you were shooting through glass, but the I read your comments that said you were shooting from inside. Well, there's not really much to comment on, but it doesn't really stir me into buying cheap lenses from eBay.
Mirror lens never really went anywhere, which is a pity....but f/8 really doesn't help. and the circles in OOF are not very pretty.
The Chinon lens is probably a good buy when a long lens is essential, I'm currently using a Tokina zoom (f/4.5) which is quite sharp. Modern long-lenses are amazingly expensive and hardly justify the money for occaisional use. Mine attaches to a tripod and the camera to the lens, I don't trust the camera tripod bush.....
Chinon also got some decent stuff, but I try to stay away from anything over 135mm in M42/vintage lenses, but there's a bunch of excellent 28mm, 35mm, 50mm, 135mm, and a little bit in between (although those may be pricier such as the helios 40 for example or the takumar 105mm)
I use maybe a dozen of vintage M42 mount screw lenses, they range from slightly above average to excellent, I wouldn't say that some can compete with L series canon lenses and other high end stuff, but in a less demanding configuration, such as video (as opposed to photography), APS-C crop sensors etc... they really offer the best they have. If you don't know what to go for, Carl Zeiss Jena (or ausJena) and Takumar are usually from very good to excellent, chinon has some good stuff but it's less known, vivitar is decent and basically you'll have to figure things out on your own a little bit too but it's really worth it.