That's probably my fault with the original recommendation for the OP to not go with the 45 Tessar if he had a chance to get and use one of the 50 Planars.
The 45 is pretty great for such a dinky lens, and it hardly weighs more than a small bag of potato chips. It is really sharp, and I'd challenge people to compare photos taken with it with photos taken with the latest model of Elmar-M which is also a Tessar, and see any difference. So, I do realize that.
I'm not smitten with the Elmar-M either, it's just a personal preference of mine as to rendering, and the 45/2.8 is superb if that's the look you want day in and day out. Nothing wrong with that, perfect if that's your thing. So, please accept my apology if I gave the impression that I thought it was a poor lens. It isn't. But, it doesn't provide photos like either of the 50 Planars, and vice versa. Pick the lens you want depending on your individual wants and needs. As ever.
I should have been more clear. Sorry.