Mirage From Portugal, joined May 1999, 3120 posts, RR: 16 Reply 1, posted (11 years 7 months 1 week 3 days 17 hours ago) and read 673 times:
ok you asked for examples, here are some using a Soligor 2x on a Sigma 100-300 on a Minolta 500Si, the most crapy use of three different systems/brands. Please note that this pics were all on excelent clear sunny days using manual focus. I don't suggest you a cheap teleconverter, you'll be very tired of it very quick.
Da fwog From United Kingdom, joined Aug 1999, 867 posts, RR: 9 Reply 4, posted (11 years 7 months 1 week 3 days 14 hours ago) and read 647 times:
it doesn't matter how EXPENSIVE the teleconverter - almost all cameras need a wide open aperture of F5.6 or greater to autofocus. A 2x converter reduces your max. aperture by 2 stops, so to autofocus using a 2x converter means your original lens needs to be F2.8 or better.
The alternative is approx £8,000 for the Canon 600mm f4!
But Chris makes a very important point - many cameras will not autofocus with a teleconvertor attached - one of the reasons I chose the EOS 3 for my replacement system was the fact that it could still autofocus with an effective aperture of f8, but this facility is rare, and it must be said that autofocus is much slower with the convertor attached.
But that aside, image quality should not be a problem if you buy a top quality convertor. Experience with "bargain" convertors suggests these are a mistake.
Staffan From , joined Dec 1969, posts, RR: Reply 9, posted (11 years 7 months 1 week 3 days 12 hours ago) and read 625 times:
As my camera was bought in 1985, the autofocus is so slow that I can't even focus at a moving aircraft (perhaps if it's taxiing), I always shoot in MF. So not having the fucus available is no big problem, quality is however important to me. I was looking at a Minolta converter.
Da fwog From United Kingdom, joined Aug 1999, 867 posts, RR: 9 Reply 10, posted (11 years 7 months 1 week 3 days 11 hours ago) and read 628 times:
Well, the quality issue depends on your optics overall. A teleconverter will only make a poor lens worse. Having said that, many professional photographers will shoot with a converter on an already long (and expensive) lens, in order to avoid an even MORE expensive (and ridiculous) lens.
I shoot with a Sigma 70-200 F2.8 + Sigma's matched "ex" 2x converter when I need it - the results are good, but the glass is significantly more costly than what you have (samples below). My only occasion to try an inexpensive teleconverter with a 70-300 F5.6 zoom, a few years ago, was disappointing, and I would not recommend it, unless you don't mind spending the money on experimenting. It might well work for you (after all, Luis has some fine shots), if you accept the likely limitations.
Staffan From , joined Dec 1969, posts, RR: Reply 11, posted (11 years 7 months 1 week 3 days 11 hours ago) and read 621 times:
Thanks, your photos are really great
I'll see if I can borrow one to start with to see if it will work out. The lense I use is apparently a rather good one. I bet the best thing is to us a minolta converter with a minolta lense, is that correct??