BELOW ARE SEVERAL RESPONSES IN ALL CAPS TO SEVERAL QUESTIONS: My 1n manual says nothing about metering problems with IR, only focus problems. And if a meter has a problem with IR, wouldn't a 25 or 29 filter cause problems with metering normal film? After all, a blue green filter would block most of the transmission of red light in general, wouldn't it? SINCE CAMERA MANUFACTURERS DON'T PUBLISH THE LIGHT SENSITIVITY CURVES OF THEIR METERS IT IS NOT POSSIBLE TO KNOW EXACTLY WHAT THE EFFECTS THE VISIBLE RED FILTERS WILL HAVE ON THE METER SYSTEM. I WOULD ASSUME THE IR BLOCK FILTER IS A VERY SHARP CUTTING FILTER THAT BLOCKS LIGHT MAINLY OUTSIDE THE VISIBLE SPECTRUM, AND STILL LETS IN ENOUGH RED LIGHT. I'LL LET YOU KNOW WHEN I GET MY FILTER TESTED. Well it [THE DIAGRAM SHOWING IR LED'S IN IS LENSES] isn't in the "L EF Lenses" literature, there are half schematics with no reference to "IRLED." I don't remember such from the 1v lit, either, but could be mistaken. I'm not sure what an IRLED would do for IS. But wouldn't it emit outward, rather than inward towards the film. What possible function would it have involving TTL or distance to film plane? IT IS IN THE EOS1V TECHNICAL BROCHURE. I DON'T KNOW IF CANON REGULARLY MAILS OUT THIS PUBLICATION. I'VE ONLY SEEN IT AT TRADE SHOWS. YES IT WOULD PROBABLY EMIT OUTWARD, NOT DIRECTLY TOWARDS THE FILM, BUT THIS OUTWARD LIGHT COULD EASILY BOUNCE AROUND AND CAUSE POSSIBLE FLARE IF THE LENS IS NOT WELL BAFFLED. So what you're saying is that the red filter will prevent the camera from focusing on blue and green wavelengths and shift its focus more toward the red end of the spectrum, correct? And then the DOF at 5.6 is deep enough to accomodate the IR wavelength focus? YEP, PRETTY MUCH. ALL LENSES ARE A LITTLE BIT DIFFERENT, BUT AS A GENERAL RULE THIS IS RIGHT. One other question -- why is it so important to camera manufacturers to prevent their AE cameras from metering IR light? If the amount of IR light in a typical nature scene is approximately proportional to the amount of visible light, why is it such an issue? Are there special conditions that have IR light in wildly varying proportions? Do these internal AE filters block UV light too? IT IS IMPORTANT BECAUSE THERE ARE MANY SPECIAL CONDIDTIONS. FOR EXAMPLE SHOOTING INSIDE UNDER TUNGSTEN LIGHT, SHOOTING UNDER FLUORESCENT LIGHTS, SHOOTING EARLY OR LATE IN THE DAY (SUNRISE, SUNSET PICTURES). I've just looked through the EOS-1V and the EOS-3 pamphlets, neither has the exploded IS mechanism diagram, I would be interested to hear from anyone who has found the reference of IR LED. LIKE I MENTIONED ABOVE IT IS IN THE 1V TECH BROCHURE. However, I did notice while the -1V literature does say the film transport is "compatiable with IR film", the -3 literature doesn't, and we have all heard of (slight) fogging of the edge of IR films in -3. Off hand I do not know what difference the film sprocket hole counting mechanism between the two bodies are, I had thought they were the same...... THE 1V HAS AN OPTICAL ELEMENT ABOVE THE IR LED WHICH FOCUSES THE LIGHT AND ALSO HAS A MASK TO PREVENT THE LIGHT FROM BOUNCING AROUND. PEACE, ROLLAND * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
