I have evidently the A7. So chose the right model unknowingly?
It's a lot more forgiving with wide angle rangefinder lenses than the R and it does have the electronic first curtain so there is no mechanical movement whatsoever before the exposure is made which is a real bonus when shooting at low shutter speeds with these lightweight cameras.
My 12MP a7S does even better though as its large sensor buckets gather light even more efficiently in the far corner with wide angle rangefinder lenses, has not color cast issues and can of course shoot at insane ISO values like the Df and the D4 series but like those cameras has less DR than the higher MP models.
B&H did a comparison of the original a7 series and used the 15/4.5 to show the vignetting and colour shift proporties of these three cameras:
http://www.bhphotovideo.com/explora/photography/buying-guide/sony-a7-series-which-model-suits-you-best%3FThe a7 does still vignette but less than the R and the color casts are almost gone, as you can see the R is almost unusable with this lens.
A side node for the 15/4.5 specifically btw is that it does vignette more at infinity focus because the rear element extends closer to the sensor making the angle of the light hitting the far corners even more steep. So use hyper focal distance focussing to get the best performance out of this lens, on the a7R I shot this lens in B&W to get rid of the color cast and usually dialed it in at 1.9 meter and f8 or so to get everything in focus with the least amount of vignetting.
