For my money, this holding of focus while zooming out is how zooms are supposed to work. Vivitar made some good lenses that were 'Vara-focal' and not true zooms that maintain focus as you zoomed. I understood that relaxing that requirement was what let them get better performance. Regards, Bob S.
[EMAIL PROTECTED] writes: > This is an excellent zoom lens and the focus does track very well through the zoom >range. > Since the aperture remains constant through the zoom range, depth of field >diminishes as > you zoom in from 35 to 105 mm. The narrow DOF makes critical focus easier. At 35 mm, >the > DOF is wide and critical focus is more difficult, but it usually doesn't matter as >much > because the DOF is very wide (compared to DOF at 105 mm). What I'm saying is that the > focus doesn't change when you focus at 35 or 50 mm and zoom in to 105mm. I'm just >saying > critical focus acceptable at 50 mm is easier done at 105mm > because of the narrower DOF. > The SMCA 70-210 f/4 is the same way. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
