aside from the three mentioned, what is your total investment in EF-S long glass? what long glass do you reach for when needed?
I was wondering, just how much can you invest in EF-S long glass? (Or, perhaps, how do you define long glass? ) The 55-250 is the longest EF-S lens offered, following the 18-135. Everything else tops out at 85, I believe. EF-S lenses are designed to give croppers the FOV of wider EF lenses. There is no demand for long EF-S lenses, since people use long lenses to "reach." I mean, who would buy an EF-S lens with the FF FOV of the 100-400 when they can use the 100-400 perfectly well and get 1.6x the "reach"?
I know what you mean, so not to pick nits here but to be more precise I would state the objectives of EF-S this way:
1. one of the primary intentions of the UWA EF-S lenses is to give the cropper the FOV of longer EF lenses when used on FF bodies. (10mm on a APS-C gives the equivalent FOV to the longer, 16mm on a FF).
2. All EF-S lenses benefit from a reduced cost of R&D and mfg, arising from the fact that the image circle does not have to accomodate the larger FF sensors. therefore, the lens can be produced cheaper with equivalent or similar IQ compared to a FF lens. As a matter of practice, certain EF-S lenses bear this out, i.e. 10-22, 17-55, 15-85 (I think thats the "third" one...)
3. one of the secondary (imho) intensions of the longer EF-S lenses is to give the cropper a way to acheive moderately long focal lengths with a very minimal investment. The 55-250 is a great example of this.
So yes, generally the IQ aware croppers don't buy EF-S "long" glass -- most of us turn to L glass. But the casual entry level APS-C tog who just wants the full range of focal lengths can obtain coverage from 18 to 250mm with a very minimal investment.