Bob Turner > Setup - EOS 3, 300 f/2.8, 1.4x & 2x ext. and 12mm ext tube (all Canon), > tripod for the lens and a monopod for the body. I tried all the various > combinations and a range of apertures and all shots were taken > with MLU and > a remote release on Sensia 400. > > A couple of questions I need to ask.... > > 1. What is the effective focal length of the 1.4x + 12mm + 2x + > 300? I know > I have 840 (300*1.4*2) but does the 12mm tube make any increase here? > > 2. I have read that a good moon shot should be taken with at > least a 300mm @ > 1/250 & f/8 with 100 ISO film, is this correct and what > difference will the > film I used make (Sensia 400)?
Bob, Sorry I didn't answer sooner, I expected someone to chime right in (answers are often posted before I even read the mail). 1. Good question.I assume 840. For the most part, the tube changes focus and not magnification. 2. The moon is sunny 16 exposure, being in direct sun. That means that if the shutter speed is set at the ISO, then the aperture should be set at f/16. Hence your 1/250 @ f/8 is on target for 100 ISO film. For 400, increase by two stops. You might also try a half or two overexposing (for 400 ISO, 1/750 or 1/1000 at f/8) as I've usually noticed that sunny 16 is closer to sunny 11. Dave B. * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
