Archived posting to the Leica Users Group, 1999/08/28
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]If you were to focus at the 70mm focal length, and then zoom to 28mm it would still be in proper focus. The reason is that a zoom lens can focus more accurately at the longest focal length. Also, there is a difference between a "zoom" lens and a "variable focal-length" lens. A zoom lens will retain focus throughout the range while a variable focal-length lens has to be refocused at the various settings. Joseph - ----- Original Message ----- From: claire <clairetm@singnet.com.sg> To: leica-users <leica-users@mejac.palo-alto.ca.us> Sent: Saturday, August 28, 1999 6:39 AM Subject: [Leica] ... 28-70 zoom... > Dear Leicazits, > I own a demo piece of an R28-70zoom lens. I noticed this pheneomenon, not > sure if it is normal.... > > I focus on a subject 3 metres away at 28mm focal length, then I zoom out to > 70mm without re-focussing. > > The focus looks off ! ( the split collar focussing screen shows out of > focus )Is this normal ? > > Rgds > TMLee, S'pore > >