SILLY ME I THOUGHT THEY WERE DESIGNED TO MEET A SPEC.
jco
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Kent Gittings
> Sent: Tuesday, November 13, 2001 9:54 AM
> To: [EMAIL PROTECTED]
> Subject: RE: 200 f2.5 question, how can filter ring be 77mm?
>
>
> The 2 things you have to remember are that both the aperture and focal
> length of the lens are rounded off by the lens maker. Nobody advertises
> their lens is a 192mm F2.53, they all say 200mm F2.5.
> Kent Gittings
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Knut Kampe
> Sent: Friday, November 09, 2001 12:59 PM
> To: [EMAIL PROTECTED]
> Subject: Re: 200 f2.5 question, how can filter ring be 77mm?
>
>
> At 09:18 09.11.01 -0600, you wrote:
> >Lets not forget in this discussion of the maximum f/stop of a
> >lens that the f/stop measurement is taken from the relationship
> >of the entrance pupil and the focal length. The actual diameter
> >of the front element is not part of the equation.
> >William Robb
>
> How can the entrance pupit be BIGGER than the the actual front diameter? I
> don't think that this is possible (the opposite is sometimes the case).
>
> Knut
> -
> 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 .
>
>
>
> **********************************************************************
> This email and any files transmitted with it are confidential and
> intended solely for the use of the individual or entity to whom they
> are addressed. If you have received this email in error please notify
> the system manager.
>
> This footnote also confirms that this email message has been swept by
> MIMEsweeper for the presence of computer viruses.
>
> www.mimesweeper.com
> **********************************************************************
> -
> 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 .
-
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 .
