That's not quite the correct answer. As you pointed out in another reply, you meant a variable aperture lens.
For a zoom or varifocal lens, even with a fixed maximum aperture, there is a potential problem if you are using a ttl reflected light reading. As you increase and decrease the focal length you change the angle of view, which in turn changes the area covered. There could easily be an overall change in reflectivity. -- Cheers, Bob > -----Original Message----- > From: Shel Belinkoff [mailto:[EMAIL PROTECTED] > Sent: 19 May 2005 14:17 > To: [email protected] > Subject: Re: Understanding exposure? Recommendations? > > Exactly! > > Shel > > > > [Original Message] > > From: Doug Brewer > > > On a lens that changes from 4.5 on the short end to 5.6 on the long > > end, it's difficult to ascertain exactly where it changes, so you > > don't know which value is being used, thus making it harder to > > determine the exact exposure. > > > > At least, this =seems= to be what Shel means. > > > > > > frank theriault wrote: > > > On 5/18/05, Shel Belinkoff <[EMAIL PROTECTED]> wrote: > > > <snip>Do not use a > > > > > >>variable focus zoom lens when learning exposure. <snip>
