Hi Jonathan ----- Original Message ----- From: "Jonathan Kwok" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, October 20, 2001 4:10 AM Subject: RE: EOS 70-200L IS - First impressions
> My other concern was the loss of micro detail and lower light transmission > due to the extra glass. I mean, it could be rated at f/2.8, but may actually > transmit marginally less light due to internal reflections. No work, turning sad, conducted a comparison test of IS and Non IS lenses. 1N body mounted on solid tripod, mirror-up, subject = wooden shed (low contrast) with chrome padlock in overcast lighting at about 12 ft. Velvia. Sequence = at 70mm, f/2.8, f/4, f/5.6, f/8, f/16, f/32. At 200mm, same. With Mk1 2x Extender at 400mm, f/5.6, f/11, f/22. Then again at 400mm but at about 100ft distance, subject = red brick wall. The subject was initially auto focused (central point), then the AF switched off for the sequence. This should have eliminated any potential differences caused by failing eyesight! IMO, the only significant optical difference between these lenses is the performance at f/2.8. Both lenses tend to give similar slight underexposure wide open but the IS lens is also slightly "softer". This is considerably more noticeable with the 2x Extender. In fact, I'm not sure I would want to use the combination wide open, whereas I had no hesitation with the Non IS lens. So your concern regarding micro detail/contrast seems well founded. This was corroborated, perhaps, by the AF performance of the IS lens with 2x Extender. It was nowhere near as positive in locking focus with the distant subject. If it were not for your enquiry I would never have run a side by side comparison. Who said "Ignorance is bliss"? Craig Z * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
