01-10-2015, 03:37 AM
Regarding the price of the 35/2.8 and 55/1.8-
The 35/2.8's price stems from its ridiclous construction. It has three aspheres which are aspheric on both sides, and two of them have thin center thicknesses and must be very hard to manufacture. Three pieces of the entire 100+ part object account for almost 30% of its price tag given a value of $75 per asphere which is about right for their size.
In general the 35/2.8 is an interesting design to study - it answers the question of "is simply throwing more aspheres at it a good solution" with a resounding "no" which is nice to see, but not nice for sony. There's also a great deal of negative power towards the back of the lens, so I would imagine the exit pupil sits quite uncomfortably close to the sensor. I believe the sonnar form was a very poor choice for that particular lens, a heliar or biotar starting point could have cut the cost in half.
The 35/2.8's price stems from its ridiclous construction. It has three aspheres which are aspheric on both sides, and two of them have thin center thicknesses and must be very hard to manufacture. Three pieces of the entire 100+ part object account for almost 30% of its price tag given a value of $75 per asphere which is about right for their size.
In general the 35/2.8 is an interesting design to study - it answers the question of "is simply throwing more aspheres at it a good solution" with a resounding "no" which is nice to see, but not nice for sony. There's also a great deal of negative power towards the back of the lens, so I would imagine the exit pupil sits quite uncomfortably close to the sensor. I believe the sonnar form was a very poor choice for that particular lens, a heliar or biotar starting point could have cut the cost in half.