So I am going to be lazy and ask here before spending hours browsing the internet. Feel free to ignore me if you think I should do my own research, which I will, but if you have mercy and some time on your hands any help will be appreciated. Soo.. I grew up shooting Zenit E with some or another version of 44mm lens and that's all I had. I learned a lot using just one camera and one lens, but nothing about other lenses available in the mount. Later I switched to Nikon and that's where I've been since. Suddenly I find myself with a brand spanking new Zenit TTL and following lenses (all in like new, likely never used, condition): 1. Carl Zeiss Jena 25mm f/4 Flektogon 2. Berogon 35mm f/3.5 3. Helios 44M 58mm f/2 3a. Gelios 44-3 58mm f/2 MC 4. Revuenon-Special 135mm f/2.8 5. Iopiter-37A 135mm f/3.5 MC 6. Jupiter-6-2 180mm f/2.8 7. 3M-5A 500mm f/8 Reflex 8. MTO-1000A 1100mm f/10.5 Reflex Apart from the two Helios', which are standard and actually not as bad as one might expect, and the abominations in the shape of two mirror lenses weighing about one ton each, how are the others? Anything respectable here? I couldn't find any info on the Berogon 35/3.5 (says "Lens made in W-Germany", the lens is quite small) and not much on the Flektogon either. The 180/2.8 is I believe heavier than all my Nikons combined... What is this Revuenon-Special thingy, it doesn't look half bad? Finally, while Zenit TTL looks better than my old E in about every possible way, plus it's "new", I have doubts. Its finder is... well... not exactly bright, though not many prisms will win that contest against F3, and ffs it's Zenit which I grew to not exactly like to put it mildly (my E fell apart) so I would like to try some of these lenses on some other body. I looked at the other active M42 thread, and Pentax seems to win the "popularity" contest. Any advice? Anyone using the TTL and thinks I should give it a chance? I have various Nikkors and two F3HP, two FM, an F100, and I definitely don't intend to stop using them (I'd rather shoot myself in both knees) but these lenses are making me curious so I need to do something about it. Sorry for the long winded post, and thanks. I will get my web shovel now and start digging for info.