If you set the aperture from the body (as you have to on the *istD for example) then aperture does not vary - unless you are shooting at an aperture wider than is permissable throughout the zoom range.
My Sigma 17-35 f2.8-4 behaves like a constant F4 unless I try and shoot wider than that! I wouldn't generally look to shoot this lens wide open anyway, although have on occasion. It can be a bit of a pain on the MZ-S, but on the istD you wouldn't generally notice. Pentax will soon have a constant wide zoom for D'hood though! > -----Original Message----- > From: Bruce Dayton [mailto:[EMAIL PROTECTED] > Sent: 01 December 2003 15:26 > To: William Robb > Subject: Re[8]: Digital lens questions > > > I had been looking for a 17-35ish zoom that wasn't variable > aperture, but have not found one for in that focal length > range. The only ones are the Tokina 20-35/2.8, Sigma > 20-40/2.8 and the Pentax 20-35/4. The best the 17-35 range > gets is 2.8-4. > > Certainly the wide end is where the digitals (smaller sensor) > have more issues. There just isn't a constant aperture zoom > that goes wider than 20mm available for Pentax. > > > Bruce > > > > Monday, December 1, 2003, 6:31:48 AM, you wrote: > > > WR> ----- Original Message ----- > WR> From: "Bruce Dayton" > WR> Subject: Re[6]: Digital lens questions > > > >> That does look interesting. Too bad it is not already > out. I'm sure > >> I will have moved on before then. :( > > WR> If you haven't used zooms much at weddings, something you > may not be > WR> familiar with is the problems associated with using > variable aperture zooms > WR> and fill flash. > WR> As you zoom, if the aperture closes, your fill ratio gets > thrown off and the > WR> backgrounds change density. > WR> It may not be a big deal for some, but for me, it changes > the look of the > WR> pictures. > > WR> William Robb > > > >
