I never cease to be impressed by the amount of information that comes from members of this list on almost any possible topic.
Thanks, Walt - that's one bit of info I'll be tucking away to impress someone sometime in the future...... Cheers Brian ++++++++++++++++++++++++++++++++++ Brian Walters Western Sydney Australia http://members.westnet.com.au/brianwal/SL/ On Fri, 6 Jun 2008 08:31:22 -0400, "Walter Hamler" <[EMAIL PROTECTED]> said: > There is a formula to determine the distance (altitude). > I/F = G/A > I is image size on film/sensor > F is focal length > G is size of object on ground > A is altitude > > Plugging in some wild guess figures of .080 I, 8" FL, and 200 ft long > plane I come up with 20000 ft. > Normally contrails below 25000 ft are not normal but possible, and > absolutely my figures are wild guesses, but it's at least 20,000, > probably 30,000 feet up. > > Walt > > On 6/6/08, William Robb <[EMAIL PROTECTED]> wrote: > > > > ----- Original Message ----- > > From: "Doug Franklin" > > Subject: Re: Airplane II, The Sequel > > > > > > > William Robb wrote: > > > > > >> ... Tokina AT-X 80-200/2.8 > > >> > > >> http://users.accesscomm.ca/wrobb/temp/airplane.html > > >> > > >> I don't know how high those things fly, but its a few miles away from me. > > > > > > I don't know how high that one is, but it's considerably lower than the > > > max cruise altitude for that aircraft type if you got that much frame > > > filling with a 200. :-) Some of those big people haulers can cruise > > > close to or over 40,000 feet. > > > > The shot I posted was quite a bit of a crop. > > Heres the full frame, resized for the web and showing some interesting > > blotchiness. > > http://users.accesscomm.ca/wrobb/temp/full9861.jpg > > > > William Robb > > -- -- http://www.fastmail.fm - A no graphics, no pop-ups email service -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
