Date: Sun, 4 Dec 2005 23:31:00 +0000 From: Cotty <[EMAIL PROTECTED]> To: "pentax list" <[email protected]> Subject: Re: A better 70-200mm F. 2.8 Message-Id: <[EMAIL PROTECTED]> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit
On 4/12/05, Jens Bladt, discombobulated, unleashed: >All of them seem to suffer from Back Focus. Sorry to be a pain Jens, but the only back focus I have ever heard of in optical hardware terms is to do with manually adjusting the rear element (s) of a lens to achieve correct focus depending on what camera (video) a particular lens is mounted on. <http://www.rondexter.com/professional/equipment/adjusting_back_focus.htm> and <http://www.pentax.co.uk/cctv/technical_1.html> In a still camera application where back focus is usually not adjustable, do you mean that the lens is focussing on the wrong plane? Cheers, Cotty ____________________________________________________________________________________________ Cotty. The back focus problem a LOT of D1's suffered(as mine does) seems to be linked to a ~slightly~ out of aligned centre sensor,acording to Nikon.Although they have never officially admitted to this,will fix cameras that are sent in for the problem. Mine does this in poor light and if the contrast between subject and background is close.However its noticably in the viewfinder so for the most part i can recompose and get the shot. About the only thing the D2H does right is focus<g> and the istD has never experienced this , so far. David J Brooks Equine Photography in York Region www.caughtinmotion.com Pentax istD, Friggin Nikon D2H
