Idk which is which, but both look a little bit over-exposed to me. That said, when used wide open the aperture should look pretty much the same since they use the same optical formula (if I remember correctly), when stopping down is when the extra aperture blades should make a difference. That's the reason I'm starting to like my Helios 44 more than my Yashica 50/1.4, I usually stop down the Yashica to around f/2 to widen the DOF (yes, I said widen) and when I do I get octagons all over the background which look really unpleasing to me... stopping down the Helios the background still looks good, same with my Yashica 50/1.7 DS-M, my finger has been hovering over the "buy it now" for an ML version of my 1.7 for the whole weekend... lol.
Yeah, they are a bit over. My daughter wasn't being very cooperative today, and when I looked at the LCD, these exposure settings looked best of what I had, and the histo looked the best also. I took a grand total of 3 pics :/ before she decided she had enough. The 3rd was a bit under.
Makes sense about stopping down to see the difference. I must be weird. With all my manual lenses, I use them wide open. Always. I only use them for certain things, so it works, and I'm really going for the bokeh without having to do much work. My EF lenses are for the other stuff.
If anyone cares, the warmer pic is the Helios, and the cooler is the CZ Biotar. I really expected to like the Biotar more, but so far (and it hasn't been very long), I'm really liking the Helios. I think the colors are truer. I have another Biotar coming, and I'm going to see if there is any difference (doubt it) between the three.
In any case, I personally love the bokeh of these lenses.