On 23 Apr 2005 at 10:10, Shel Belinkoff wrote: > Too much math, not enough photography .... I don't understand the need for > equations, nor do I understand the math, the equations, or your conclusion. > > Like I said, the field of view, regardless of your math, is greater with > the Zenitar than it is with a 20mm lens on a 35mm camera. Have you looked > through both focal lengths on a 35mm camera? Have you actually compared > photos side-by-side?
>From a practical perspective you are of course correct Shel, the fisheye lens will provide a wider AOV than the a rectilinear lens of equal focal length. However due to the physics you will find that the fisheye effect diminishes as the image is cropped (and this can be easily described in mathematical terms, as Cory showed). So a 16mm fisheye on an APS sized DSLR frame looks far less fishy than you might expect. Cory said: "So, what I *meant* to say is that FOV of the fisheye is about equivalent to a 13-14mm rectilinear lens on the -DS, or a 20mm rectilinear lens on a full-frame 35mm body." How I interpreted that paragraph was that a 16mm lens on a D or DS body produces an angle of view roughly equivalent to the AOV a 20mm lens will provide on a full frame 35mm body, and I agree. Cheers, 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
