I've been shooting quite a bit with my adapted rangefinder lenses, in particular one adapted from an old Konica Eye half-frame 35mm camera as well as a Canon 50mm f1.2 rangefinder lens. It got me wondering why the Sony native lenses are so large. So I've decided to share my theories: 1) Sony has released large lenses because it is faster, cheaper, and easier to design them. 2) They are based on Sony Alpha lenses. 3) They don't care; they'd rather sell us a new body each year. 4) Sony is working on next generation lenses: a 30mm pancake and a fast 18-55 compact zoom, and will sell them as upgades when current sales subside. I hope it's "4".
I've read that it's the registration distance that is keeping lenses larger. I honestly don't know enough to know if that's right, though.
I think the registration distance is the issue as well and until Sony overcomes the technological hurdles of designing optically good, compact lenses that can take into account the short registration distance, then we will get larger lenses for the time being. But remember, the NEX lenses are certainly larger than the competition, but they are by no means huge. Sony may very well start taking advantage of micro-lenses in front of the sensor to get the optical quality they seek before releasing smaller, more compact lenses. The latest generation NEX modes are said to have these micro-lenses, so it may only be a matter of time before this happens. Remember that the lenses being released this year were likely designed well before these micro-lenses were added to the mix. Sony had a very different set of customers in mind when they released the NEX-3 and NEX-5, so I would think we are finding ourselves at a time of transition in the product road map.
The flange is only empty space so a lens would need to make up for the small registration distance. So sony could make any lens but you need to add the difference between the registration distance from nex to the other mount. (X Flange - NEX flange) + lens length = lens length with same optical formula. so a sony 30mm f2 based on Samsungs build would need to be 7.5mm longer. (25.5-18) + (22) = 29.5mm long or Voigtlander Nokton 35mm f/1.4. (27.8 - 18) + 29 = 38.8mm long the advantage of the short flange is sony could make ultra wide lens smaller than other company, but because of the thickness of the sensors at the moment they do not handle off axis light well, so smaller lens have problems with corner sharpness, color bleed, and other optical issues. But I would take all those problems for a set of small lens (and mostly only seen in wide lens aka 16mm f2.8).
There are not that many lenses out there to begin with. I think it's a bit premature to pass judgment on the design of the system and flange distance already. They have prioritised a bit differently than the mft family of lenses, not just the introductory lenses, but also the ones we see on the roadmap. I think we will see more compact lenses later on though, but don't base any purchase decision on ifs and buts.
Like the guy from Sony UK said in the live Q&A, there are going to be many pancakes in the future (let's hope for next year). As far as I think, they'll be relatively cheap (250 euro or less), don't have the best aperture (f/2 - f/2.8) and won't have the best image quality (look at the 16 mm) - but at least, they give us choice. Everyone who wants good image quality IMHO will have to buy the "big" lenses.
