Hi, > Suppose I have a 300 > mm f/5.6 lens. What film speed should I use in order to stop the action as > well as attaining good depth of focus (say, 4 m) in an artificially > illuminated stadium?
If your subject is 2m in height then to fill the frame using a 300mm lens you must be 17m away. To achieve a depth of field of about 4m your aperture must be at f/16. On a bright day you can do this with ISO 400 film at 1/500 second. According to Michael Freeman in his book "Light" all stadiums that have TV coverage use multi-vapour lamps, because these produce a colour quality close to normal daylight. He suggests that for ISO 400 film at 1/60 or 1/125 you will need an aperture of f/2.8. So to achieve a depth of field of 4m your film needs to be rated at 12,800. However, most of the photographers are probably using digital cameras, so these calculations may not apply. For example, a nominal 300mm lens is effectively longer than that, and the f-stop ratio is changed, so there may be more depth-of-field than I've indicated. These numbers are for 35mm. --- Bob mailto:[EMAIL PROTECTED] - 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 .
