Hi,
Short intro: Rather green amateur, first time poster, long time reader
(And big fan of the entire LL site - thank you Mr. Reichmann)
I have been wondering about the Canon EF-S lenses. All other disadvantages aside, the biggest issue for me, using an APS-C size sensor, is loosing the wide angle.
A rather expensive 17mm becomes 27mm due to the cropping facter and that...well... frankly, IMO sucks
So - enter EF-S. When I first read about Canon's EF-s lenses, and how they were developed especially for the APS-C sized sensors, I assumed that the reason they were made was that they were taking into account the cropping factor, making an EF-S 17mm lens a true 17mm, giving the same FOV as a normal EF 17mm would yield on a fullframe 35mm sensor.
Alas - from what I can read, this is not the case - as all reviews I read etc. always have the side note "(As compared to 27 on 35mm)".
So, I have to ask - why the EF-S lens? Is it simple production cost, and the fact that the Short back makes it cheaper to produce a 17mm Wide angle lens or am I misunderstanding what I read ?
Because frankly, I must admit I truly assumed that there could be only one compelling reason for Canon to move away from or create a parallel to their standard mount - and that would be to get the technical benefit of true wide angle. Not a "simple" factor as cost... then again... money talks I guess *shrug*