> Addressing JCO's contention that 35mm/3.5 and wide angle lenses are more > difficult to focus "in any camera". well, that's just plain flat out > wrong. Apart from wide angle lenses being more forgiving of small > focusing errors, regardless of the camera to which they are attached, > there are numerous cameras, Pentax and other brands, in which the choice > of a proper focusing screen greatly improves the ability to achieve > critical focus with a wide variety of lenses. So, to say that it's not > easy to focus these lenses in *any* camera is somewhat misleading. > Here's how it works:
The longer or faster a lens is, the EASIER it is to focus. The shorter or slower a lens is, the HARDER it is to focus. Thus for a given focal length, the faster lens is ALWAYS easier to focus, or for a given lens speed , the LONGER lens is ALWAYS easier to focus. The 28mm F3.5 and 35 F3.5 mentioned are both shorter and slower than normal, thus Much HARDER to focus relative to normal. What your talking about above is DOF at shooting aperture which is different from open aperture focussing. Yes wide angles give more latitude of focus error, but critical focus it still 1 point. JCO - 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 .
