tcmatthews said:
I fully expect that all non-USM lenses will be replaced with STM. So if you are crazy so am I. A low cost STM 50mm makes sense.
Even with the EF 40mm f/2.8 STM already in the market, often with a street price of $149? How many people who bought the 40mm STM would also want a similar (or lower) quality 50mm STM? Is there really anyone who would reject the 40mm f/2.8 STM but accept the 50mm f/1.8 STM or vice-versa given the similar focal length and budget price? How much cheaper could a 50mm STM be to make? Even if they made it ultra plastic cheapness, wouldn't it be cheaper to market one model in volume (40mm STM) then market and stock both the 40mm and 50mm STM? And there would still be no updated satisfying enthusiast model to replace the 50mm f/1.4 which has straight aperture blades and questionable AF reliability.
I just think this makes more sense:
Scenario A:
40mm f/2.8 STM (lowest cost walkaround, moderate quality)
50mm f/1.8 IS USM (moderate cost, high quality)
50mm f/1.2L USM (high cost, portrait specialty)
Scenario B:
50mm f/1.8 STM (lowest cost walkaround at 50mm & f/1.8, passable quality)
40mm f/2.8 STM (very low cost walkaround at 40mm & f/2.8, moderate quality)
50mm f/1.4 USM (low-moderate cost, moderate quality & f/1.4 but questionable AF motor reliability)
50mm f/1.2L ISM (high cost, portrait specialty)
Scenario A seems to better address the three main markets - budget minded, enthusiast, and professional.
Scenario B seems to deliver too much in the budget market, and not enough in the enthusiast market.
The only way I see a 50mm STM happening is if it is built like a POS and can be marketed at an even lower price than the 40mm STM when it debuts (i.e. MSRP 129.99). Remember, part of the reason the 50mm f/1.8 II is so cheap is because of its age as R&D was recouped long ago, not just how much it costs to make. So I do not think a 50mm STM would debut at half the price of the 40mm STM.