« on: November 17, 2014, 08:40:38 AM »
The C version will have fewer lens elements, which means lass corrections for distortion and CA's. So far, I haven't seen any test reviews of the "S" version that indicates a big advantage over the Tamron lens, that may change as more carefully done tests come in. There is always a variation in test results, so I tend to ignore the outlier results and accept the ones that are reported by the most testers. Astute lens testers also make sure that values do not exceed the MTF curves, if they do, it indicates a error in the testing.
I'm wondering if the "C" version is delayed due to manufacturing difficulties, or just to allow them to fill the huge volume of "S" orders first. I'd think its just the latter, cranking as many of the "S" lenses thru the line to meet initial demand, then starting to produce the "C" version which will sell in greater numbers for sure.
I wonder if it really is manufacturing difficulties or even allowing themselves to fill a huge volume of S orders first. More prosaically, they were in the process of finishing the design and tooling up for the S when they were taken by surprise by the Tamron and decided to build a C competitor. Also, if they marketed the C first, then it would take away from the later S sales if there wasn't that much of an IQ increase. Whatever the case, the new 100-400 L II is going to dent the opposition.