There are times when I would like just a little more focal length in my Canon EF 75-300mm f4-5.6 IS USM lens.

Is there an extender[1.4X or 2.0X] that can be used with it? Who makes it? I believe the Canon extenders can't be used with this lens.

I know using an extender might cause some limitations by cutting down the light. However, I could try the following: 1) The lens does have IS. Would that help enough? I have heard that IS may effectively add 2 f-stops to the speed of the lens... 2) Would using faster ASA film be needed? How fast? 3) I do have a 550EX flash. That could help... 4) I also have a tripod if I can't shoot hand-held... But I prefer hand-held, if possible...

-- C.A. Thorne (cthorne@us.ibm.com), December 06, 2000

Answers

Most of the 3RD party teleconverters Will Fit and work with the lens Kenko seem to be some of the better 3rd TC's ..

Is Will Help some but you didnt say what type of shooting you doing so i can tell ya if you and handhold it or need to tripod it Also if you go out to 600mm with a 2x It only takes a little Shake to blur Pic and IS might not be able to over come it ..

And on the Film Again you dont say what type of shooting your doing low light or whatever so try 400 Iso and go from there if you shooting in really Bright light maybe 200 will work ..

Also you didnt Which Camera you are useing but you will lose Autofocus With the 2x Thought most of the range of the lens and 1.4 will Autofocus only if you have a Eos 3 or a Eos 1V

Hope that Helps

Rob

-- Robert Dankert II (bobbyd7@hotmail.com), December 06, 2000.

Normally, any lens smaller than f:5.6 will not AF on most EOS cameras (1V and 3 are the two exceptions) But since third party TC's don't report the aperture drop caused by the TC, the camera will try to AF even though the aperture is effectively too small. My experience is that if you use a 1.4X or 1.5X TC the camera will AF as long as the light is sufficient and there is enough contrast. With a 2X TC you loose all AF. Even reliable AF confirmation in manual focus mode is gone. Most Canon EOS bodies don't have a view screen designed for manual focusing so this makes them difficult to use accurately. Also the 2X will cause a larger quality loss than the 1.4X or 1.5X TC's, and the 75-300 IS isn't all that sharp at the long end anyway.

I use a Kenko 1.5X TC with my 75-300 USM IS and the quality is barely passable for snapshots, but sometimes that's what I need to do to get the picture. It is hand holdable, even in less than desireable lighting. With IS turned on I can reliably hold it at 1/125 second, and with fast film that's easy to find.

-- Jim Strutz (jimstrutz@juno.com), December 06, 2000.