« on: February 23, 2015, 05:35:00 AM »
any reason all the new canon lenses are F4 ?
Explain why you need f/2.8 at these focal lengths please. Please don't say "low light capability" because if you are using a lens like this indoors in professional use you will almost certainly be using a tripod. And upping the ISO nowadays by one stop isn't a big a deal as it used to be. The 6D works nicely even an ISO 6400. I don't even use that for stars in the middle of the night so unless you are shooting in a cave in complete darkness, handheld, with an older generation camera - the reason is pretty clear why f/4 is good enough.
If not - 14mm f/2.8 is your friend.
I can answer your questions..
I use it during wedding-sessions in dark churches.. when the bride couples are moving and no.. I can't use a tripod for that.. nor the IS.
Going from ISO 3200 -> 6400 or ISO 4000 -> 8000 is quite a large step up in ISO on a 5dmkIII.
I need at least 1/160 (sometimes even 1/200) when the couple is moving up and down the aisle. Don't want pictures that are blurry from movementblur.
When I shoot landscape / indoor and people are not moving.. then I can use f4 and IS. When I shoot landscapes I often step it down aswell. (f8-f14)
Another thing.. when you shoot stars / aurora up here in the northern part of Sweden.. even F2.8 is quite small aperture. I could really use a f1.4 with a UWA.. but that's not available.