> >> If I use a 300 mm IS lens on a D30 camera, the > effective focal length > >> becomes 480 mm. Does the IS still help two stops > or does the change > in > >> focal length also change the effectiveness of the > IS. Since there is > a 60% > >> increase in focal length would there also be a > 60% decrease in the > >> effectiveness of the IS?
I think the key here is to forget about focal lengths. Image shake is a factor of image magnification, not focal length. Your 300mm lens has a magnification equal to a 480mm lens on a 35mm frame. So, following the 1/effective focal length rule, you'd want to shoot at about 1/500th second hand held, without IS. IS should still get you about 2 "stops" below this speed. ===== Bob Meyer I wish I knew what I know now, when I was younger... http://www.meyerweb.net/epson __________________________________________________ Do You Yahoo!? Yahoo! Tax Center - online filing with TurboTax http://taxes.yahoo.com/ * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
