I see! That's a clever concoction, I didn't figure out at first what that thing on top of the camera was.You are correct about the Heliar. but I was able to remove the original lens mount and put a Minolta mount on in it's place. It is NOT a retro-focus lens, so I can only use it on cameras with a mirror lock-up, such as the PANDA in the above photo. That's why there is a separate viewfinder on top of the camera.
Good to know converters aren't all equally bad, thanks.As to converters, quality depends on the converter, how it is used, and most importantly , the lens to which it is attached -- and how it is used. Lots of people will trash any converter -- but there are lots of people that even trash the use of a UV filter, for Pete's Sake. Minolta, Nikon, Sony, Tokina and lots of other companies made great converters that they felt met their standards. You'll have to decide if they meet yours. I use various converters all the time, and I have no complaints -- but I use them carefully and correctly.
I've assembled a pretty extensive collection of fast fifties in m42, excepting such expensive rarities as the Pancolar f1.4, and it would be stupid to complain that the better ones aren't good enough. Of course there are technically more perfect lenses in mounts that didn't stop production in the '70s, but it would make sense to shoot those on their native bodies. What I'm mostly curious to know is if there are interesting lenses in mounts that didn't live past the '70s, which it would make sense to convert for the sake of their 'character' (rather than technical perfection) -- the Petri f1.4 being one such case...I offered you a possible path to accomplish what you want to achieve. The key word is "possible". Just because it works for me and my gear, does not mean it will work for you and your gear.
If you are a Converterphobe then your best approach is to stick to M42 lenses -- as suggested. There are around 2,000 lenses to choose from -- often at giveaway prices. I provided a link to the list in a earlier post.
By the way, did you notice if a converter with glass elements affects the lens's rendering? I mean, would for instance a Helios 44 still produce swirly bokeh?