Few questions I can't seem to find answers to! For starters, I'm shooting on a GH4 with the Helios 58mm I'm currently waiting for my diopter set to ship, but in the mean time I was playing with the lens and I can't seem to get a sharp image out of it without any filters. Is this normal? The lens is in pretty good shape for being from the 50s. Also, given my set up, is it recommended to use the Tokina +0.4 achromat?  Only other bummer is the serious vignetting when using my Voigtlander .95 25mm,