The next E-mount camera I bought and quickly sold was the NEX-5, as it did not add much to the NEX-3 and I had decided to buy a NEX-5N to mod to full-spectrum. It was great that with the NEX-5N, Sony had addressed some of the issues with the NEX-3.
NEX-5N improvements on the NEX-3:
1) More megapixels (16MP vs 12MP), which will allow for more cropping of photos if needed.
2) Improved custom white balance system which works both in UV and infrared.
3) Useable up to ISO 3200.
4) Now it had a touch screen as well.
But it still had pretty slow autofocus, it still lacked a dedicated hotshoe (solved with third party hotshoe adapter), the menu system was the same, and it still only had one saved setting for custom white balance. But things were looking promising.
The next camera which came along was the NEX-7, and I could not wait to get it. When it did arrive, there were many things I liked about it, including the images at base ISO particularly when paired with the Sony 24mm F1.8 Zeiss lens, which was able to do those 24 megapixels justice.
NEX-7 improvements on NEX-5N:
1) Great looks and feel in the hand, with tri-navi system to make changing settings easier.
2) 24 megapixels and a very good sensor at base ISO (but in my view only useable up to ISO 1600)
3) It now has a built-in hotshoe (although it is the older Minolta hotshoe), as well as a useful built-in flash.
4) An improvement in the menu system courtesy of the tri-navi.
5) Excellent electronic viewfinder (EVF).
But the NEX-7 autofocus was still rather slow with no improvement over the NEX-5N, it lacked a touch screen, it still did not have a port for wireless remote, and only had one custom white balance setting.
When the NEX-6 was released, it promised faster autofocus courtesy of having on-sensor phase detection autofocus points. I thought this would solve the slow autofocus issue which affected the E-mount cameras up to then, and hence I sold my NEX-7 and bought the NEX-6.
NEX-6 improvements on the NEX-7:
1) A multi-function hotshoe useable with flash from other camera systems.
2) Faster autofocus, including phase-detection autofocus focus points ( but still slower than many other mirror less cameras).
3) ISO useable to 3200. I did not feel the ISO 6400 was as good as that I get with my Olympus EM-5 though.
4) Ability to use Apps on this camera.
But I did feel that the drop down to 16 megapixels from the 24 megapixels of the Sony NEX-7, was a back step. Whereas the NEX-7 and Sony 24mm F1.8 Zeiss lens were a perfect match, somehow I did not feel the results from the NEX-6 justified me keeping this lens, which is why I also sold this lens.
It was at this time when I wondered if Sony would ever improve the autofocus speed of their E-mount cameras to make it fast enough – I did not think the NEX-6 had reached that level. This was the time when Olympus had released the Olympus OMD EM-5 which had a very appealing retro look, very fast and accurate autofocus, amazing 5-axis in-body image stabilisation and a great sensor (courtesy of Sony). Hence I bought the EM-5, and sold the NEX-6. At that time I did wonder if I would get back into the E-mount system again.