An EF-S zoom fisheye and a wider replacement to the EF-S 10-22?
My impression was the EF-S 10-22mm should be upgraded, specifically to have wider short end and maybe some IQ improvement.
An EF-S fisheye zoom? Does the Tokina 10-17mm sell that well? After years of not making any circular fisheye lenses (note there was one for the FD mount), does Canon suddenly see a market for those on both FF & APS-C? Wouldn't it compete with both the upgraded EF-S 10-22mm and the EF 8-15mm L, which serves as diagonal fisheye lens for APS-C?
My guess is the Sigma 4.5mm full fish eye has enough sales that Canon wants to compete?
Possibly, but a fisheye zoom might mean Canon would shoot itself in the foot with an expensive lens, sending customers to buy cheaper primes.
When the EF 8-15mm f/4 came out, I already had an EF 15mm f/2.8. Preferring to save money and keep the extra stop, I bought the Sigma circular fisheye.
In case somebody brings up the familiar ISO argument:
1. An f-stop gives a 1 f-stop advantage, whether on my current camera or any other camera I will own in the future.
2. DxO doesn't support the EF 8-15mm. Support was planned, until the lens was released, then the lens disappeared from the list.