Well, Imaging Resource has some test shots from the RX100iv, and using that as a comparison of what the RX10ii will be like, I've compared their shots with the a65
a65 are all f/8 at 70mm
RX100iv are all f/5.6 at 25.7mm
RX10 ISO 125 http://www.imaging-resource.com/came...LI00125NR1.HTM
a65 ISO 100 1/20 http://www.imaging-resource.com/PROD...A65hSLCON1.HTM
RX100iv ISO 125 1/25 http://www.imaging-resource.com/PROD...LI00125NR0.HTM
ISO 200
RX10 http://www.imaging-resource.com/came...LI00200NR1.HTM
a65 1/40 http://www.imaging-resource.com/PROD...LI00200NR1.HTM
RX100iv 1/40 http://www.imaging-resource.com/PROD...LI00200NR0.HTM
ISO 400
RX10 http://www.imaging-resource.com/came...LI00400NR1.HTM
a65 1/80 http://www.imaging-resource.com/PROD...LI00400NR1.HTM
RX100iv 1/80 http://www.imaging-resource.com/PROD...LI00400NR0.HTM
ISO 800
RX10 http://www.imaging-resource.com/came...LI00800NR1.HTM
a65 1/160 http://www.imaging-resource.com/PROD...LI00800NR1.HTM
RX100iv 1/160 http://www.imaging-resource.com/PROD...LI00800NR0.HTM
ISO 1600
RX10 http://www.imaging-resource.com/came...LI01600NR1.HTM
a65 1/320 http://www.imaging-resource.com/PROD...LI01600NR1.HTM
RX100iv 1/320 http://www.imaging-resource.com/PROD...LI01600NR0.HTM
ISO 3200
RX10 http://www.imaging-resource.com/came...LI03200NR1.HTM
a65 1/640 http://www.imaging-resource.com/PROD...LI03200NR1.HTM
RX100iv 1/640 http://www.imaging-resource.com/PROD...LI03200NR0.HTM
ISO 6400
RX10 http://www.imaging-resource.com/came...LI06400NR1.HTM
a65 1/1250 http://www.imaging-resource.com/PROD...LI06400NR1.HTM
RX100iv 1/1250 http://www.imaging-resource.com/PROD...LI06400NR0.HTM
ISO 12800
RX10 http://www.imaging-resource.com/came...LI12800NR1.HTM
a65 1/3200 http://www.imaging-resource.com/PROD...LI12800NR1.HTM
RX100iv 1/2500 http://www.imaging-resource.com/PROD...LI12800NR0.HTM
Well, from the looks of things, it looks like the image quality hasn't caught up to APS-C yet, but it's pretty darn close.
What the RX100iv looks like compared to the a65 is a sensor without the AA filter, giving it something slightly crisper, but due to the smaller sensor size, it isn't able to capture all of the same detail the a65 is able to.
What I found interesting is that the translucent mirror in the a65 technically should cut off about 33% of the light it receives (which is why the noise performance of the SLT range isn't as great as comparative cameras) but based on the settings used, it seems like the RX100iv need more light to get a balanced image, compared to the a65. Could it be simply due to the size of the lens? Would the RX10ii fair any better?
What I did was try some noise reduction to compare the images and though both ended up looking nice, the RX10ii still had too many image artifacts. Once assumption could be the noise reduction - I believe on the RX100iv, it was turned off, thus we have all the artifacts.
So, I did the closest thing I could do to check the quality:
a65 ISO 6400 http://www.imaging-resource.com/PROD...LI06400NR1.HTM
RX10 ISO 6400 http://www.imaging-resource.com/came...LI06400NR1.HTM - Noise reduction on low
The amount of noise is very similar, though the RX10 has slightly more, it does look a little more crisp. With the new sensor onboard, the assumption is that we should see an improvement.
One thing to note is that the RX10 is able to still capture some part of the pattern on the red fabric on the right until ISO 3200, compared to the a65 at ISO 6400. That's very close.
ISO 200 was the RX100iv's limit, losing all hope at ISO 400 already.
Obviously, I'll have to wait for an official RX10ii review to confirm results, but based the RX10 vs a65, there's high hopes that the rX10ii should have at least equal, if not, more image quality, even though it's a smaller sensor.
It looks like my upgrade to the RX10ii is becoming more justifiable - I'm happy. New features, everything.