Hi Alex, I know theoretical DOF at f22 is enough to get about everything, since being a landscape you usually won't tend to have anything at 2.5ft you want to keep in focus. Using hyperfocal distance I doubt I'd be at f22 anyway- probably will stay around f8-f16. But what I was considering is that using it at f22 on the Pentax means I'd be using it stopped all the way down (and performance at either extreme usually not as good as somewhere in the middle). I mean I'm guessing f22 on the Sigma 17-35 (instead of at 32) could be a better performer at that aperture than the Pentax. But then again I could be mistaken. I'm still researching..
Regards, Ryan ----- Original Message ----- From: "alex wetmore" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, December 07, 2003 2:12 AM Subject: Re: Shopping for an ultrawide.. any advice? > On Sun, 7 Dec 2003, Ryan Lee wrote: > > 1. It's Pentax- so yay for SMC and resale value etc.., and it's got a small > > enough thread for the filter. Only possible negative thing I can think of- > > it only goes down to f22. > > DOF on a 20mm lens at f22 is already so great that I can't see any > advantage to f32. A sharper image would be obtained at f22 with a > ND filter than what you could get with an f32 exposure. > > It's a Pentax, it is prime, if it isn't a dog and is reasonably priced > I can't see picking anything else. > > alex > >
