Anthony writes 'tele shots from above will flatten out whatever precious little modelling you might have'. If he means that the lens will change the perspective, he is wrong. If he means that haze will degrade the image he is right. Light scatter from moisture, or other nastier particles, increases, the longer the path to the subject and contrast will suffer.
But a telephoto lens does not change perspective - although this might seem to be so. Trees in the distance, that might be miles apart seem bunched together in a picture taken with a 1000mm tele; or a picture down a long stretch of highway may seem to put cars, that may far apart, right next to one another. To demonstrate this, enlarge an area equivalent to that covered by the telephoto lens of a landscape taken with a normal lens of the same scene. You will find the perspective matches - so does the contrast. Of course you have to ignore the increase in grain and loss of sharpness. D Dr E D F Williams http://personal.inet.fi/cool/don.williams Author's Web Site and Photo Gallery Updated: March 30, 2002 ----- Original Message ----- From: "Anthony Farr" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, August 27, 2002 6:43 AM Subject: Re: Aerial photography question > Some good advice already, but hear's my 0.02c from personal experience. > > Avoid picture taking while the 'copter is in a hover because the vibrations > are more extreme. > > Worst time of day is between 10am and 2pm standard time because there is no > cross lighting to accentuate details. The best times are the first 2 hours > and last 2 hours of daylight, and the morning is usually the most haze free. > > Get as low as the pilot will dare, because distance (and altitude) in aerial > photography introduce haze. Tele shots from higher up will flatten out > whatever precious little modelling you might have. > > Periodically look to the horizon to avoid airsickness, although I'm sure > that helicopters don't induce airsickness like small 'planes do. > > Have NO LOOSE GEAR anywhere near open windows. Everything needs a strap or > tether including your glasses if you wear them. > > Watch the weather reports for mountains in your area. The temperature at > altitude will be closer to mountain temps than ground temps. I recall > turning up to a job at a town at 1000m ALT where the temperature was > pleasantly warm. However snow was forecast for 1500m and above, so I > carried my ski parka with me, to the mirth of my associates. Ten minutes > later I could have sold that parka for almost any sum I could name, but then > I'd be freezing my own arse off :-) > > Regards, > Anthony Farr > > ----- Original Message ----- > From: "Chris Brogden" <[EMAIL PROTECTED]> > > > > > I have a chance to do some aerial photography from a helicopter, and I was > > wondering if there were any tricks or not-so-obvious things that I need to > > know. I've heard that it's best to overexpose by a stop or two to prevent > > the camera's meter from being tricked by the brightness, but I'm not sure > > how accurate this is. Any thoughts or suggestions? I'll be using a > > Pentax body or two with some fast glass and a beanbag (do they help?), but > > I'll be bringing along a Canon Elan 7 with the 28-135 USM IS lens just to > > try the Image Stabilization. Any help or tips would be appreciated. > > Thanks! > > > > chris > > > > > >
