It appears that highest Quality lenses for mirrorless cameras are not smaller to build than there Counterparts for DSLRs.
All is a question of compromises and where you make it : size and weight ? max aperture ? image quality (sharpness, distortion, aberrations etc.) ? built quality and material quality ? or price ? You can't get all at the same time.
But I think that apart of a few lenses (28mm F2.8, 35mm F2.8 and 55mm F1.8) we are getting way too heavy lenses. Sony made a compact body, but doesn't care about the lenses sizes. The choice of material could help with the weight.
Here is an example of the lenses available for the Zeiss Contax G RF and those lenses are full frame :
16mm F8 (a stellar lens, no distorsion).
Close focus : 0,3m
Optics : 5/3 (lenses, groups)
Max aperture : F8
Blades : none
length 11mm
Weight : 125gr
21mm F2.8 a superb lens, very sharp and without distortion.
Close focus : 0,5m
Optics : 9/7 (lenses, groups)
Max aperture : F2.8
Blades : 7
length : 35.5mm
filter size : 55mm
Weight : 180gr
28mm F2.8
Close focus : 0,5m
Optics : 7/5 (lenses, groups)
Max aperture : F2.8
Blades : 6
length : 30.5mm
filter size : 46mm
Weight : 150gr Sony FE 28mm F2 : 200gr. I'd have preferred one with slower max aperture, but lower distorsion.
35mm F2 could be sharper in the corners
Close focus : 0,5m
Optics : 7/5 (lenses, groups)
Max aperture : F2
Blades : 7
length : 31.5mm
filter size : 46mm
Weight : 150gr Sony 35mm F2.8 : 120gr.
45mm F2 incredibly sharp
Close focus : 0,5m
Optics : 6/4 (lenses, groups)
Max aperture : F2
Blades : 6
length : 63mm
filter size : 46mm
Weight : 190gr Sony FE 55mm F1.8 weight : 280gr. the Sony Zeiss lens is superb but the 1/3d larger max aperture cause an increase of 100gr.
90mm F2.8
Close focus : 1 m
Optics : 5/4 (lenses, groups)
Max aperture : F2.8
Blades : 6
length : 35.5mm
filter size : 46mm
Weight : 150gr There is no light short tele for the Sony FE system. The
90mm F2.8 macro is huge and
weight 425gr.
The Contax G lenses have compromised on both the max aperture and some aberrastions like fringing and exhibits a harsh bokey. But they are usually extremely sharp and well corrected (little distorsion). I think the material used explain part of the light weight, plus the lower number of lenses and groups and the lower number of blades.
For the A7r, there are only three light lenses of this kind : the FE 28mm F2, the FE35mm F2.8 and the FE55mm F1.8 (already quite bigger). There are no short tele available in that category, no wider angle than F28mm; instead of continuing to develop this line, we are getting lenses so big they are unbalanced on the A7x bodies.
The question for me is: If one wants to use such lenses, are the Sony A7 series bodies size appropriate for a compfortable handling?
I expect Sony will present a Little bigger proffessional Body in the future. But thats just my guess.
Good question !
It is as if Sony started small and with the E-mount in order to lure Nex owners to jump into full frame, but then this didn't succeed, so they surrendered to the vocal crowd whinning for faster lenses on bigger bodies. The development of the FE mount is erratic to say the least.
May be that if we whine as loud as the crowd asking fast lenses, Sony will hear us in the end and keep a line of small sharp distorsionless primes adapted to the small bodies : who knows ?