Originally posted by Nicolas06 Sigma only get the one with enough money that need fast focussing for sport.
Or the one (like me) that want a higher quality walk-around with a little broader range. I recently bought the Sigma 17-70/2.8-4.0 (C) which, while not expensive, is not exactly cheap either.
I also own the Sigma 50/2.8 EX DG Macro which is neither a sports lens or particularly expensive.
Steve
---------- Post added 08-15-14 at 07:40 PM ----------
Originally posted by monochrome if I'm incorrect in physics it's OK to correct me. I'm just thinking marketing.
Heck, I don't know either way. I do know that bloated size has little to do with APS-C vs. FF. Ditto for wide maximum aperture. My smallest SLR lenses are fast (wider than f/2.8) and made for 35mm film and, no, none are pancakes.
IMHO, the relative slowness of most modern lenses has little to do with lens design or format and everything to do with auto focus. If you make a fast AF lens longer than 35mm for a digital SLR you are going to hear anguished screams regarding AF performance. After all, only the higher end AF systems are able to focus reliably at apertures wider than f/5.6 and even the better systems are limited to f/2.8 and then only for the center region AF points. I also believe that is why the split-image viewfinder is typically not found on AF cameras. Having one shows the hit/miss nature of the AF system.
...end of rant.
Steve
---------- Post added 08-15-14 at 07:45 PM ----------
Originally posted by ElJamoquio Actually he's quite correct. His physics and math are sound.
I don't know what Falk does for a living, but my understanding is that he has a doctoral degree in Physics.
Steve
---------- Post added 08-15-14 at 07:47 PM ----------
Originally posted by jatrax In this case maybe heading for the basement would be better.....................
Aunty Em! Aunty Em!
Steve