What Rob said. :)
I used sloppy terminology. I just find it easier to think in terms of focal length vs. AOV. It's easier, for me at least, to think of a 50mm lens as a 75mm lens when used on the *ist D. Multiplying by 1.5 is not over my head.
By "rated" I meant that the image presented to the capture medium at the focal plane has the same angle of view one would expect when that focal length lens was used on a 35mm body as originally intended.
Tom C.
From: "Rob Studdert" <[EMAIL PROTECTED]> Reply-To: [email protected] To: [email protected] Subject: Re: Future of DA lenses Date: Thu, 31 Mar 2005 17:38:31 +1000
On 30 Mar 2005 at 23:21, Godfrey DiGiorgi wrote:
> What is a "rated focal length"? > > How do you use a lens at anything other than its actual focal length? > Whether projecting onto a 16x24mm format or a 24x36mm format, a lens' > focal length does not change.
I assume that Tom's comment meant to something like "the lenses design coverage
and suggested AOV on a 35mm frame", that sounds reasonable, not too perplexing.
Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
