>From: Jay Todd <[EMAIL PROTECTED]> >To those that have used a 2X tele-extender with a telephoto (200 or >300mm), what do you seem to find to be the compromising element...loss >of sharpness, contrast, etc?
That's exactly it. Usually, it is the loss of sharpness that was noticeable, because loss of contrast can be corrected for more readily. I found 300/2.8A* and 1.4x-AS to be useable, but noticeably less sharp than the tele alone. I had a Tokina 2X that was not great with any lens. The loss of light can also be an issue, making it hard for you or any AF system to focus well if the combo is slower than f/5.6. > When I used a 300/4A* with a 2x-AS I was >always impressed with its results. But now with another system I'm >getting a slightly diffused image with a 70-200/2.8 and 2xEF, more so >than I would have expected. The basic opinion I have seen expressed by many pros that use tele extenders is that 1) 2x extenders are not as good as 1.4x extenders. Very few people I know use a 2x, whereas a lot of them use a 1.4x. I have not read many favorable reviews of 2x converters, and my own limited experience bears this out. 2) zooms are normally VERY POOR with tele extenders compared to primes, and the standard advice is NOT to use any extender with a zoom. Recently, I am hearing that the new 70-200 Nikon and Canon zooms appear to have adequate performance with a 1.4x extender, but it's a combination used out of necessity for most people and I can't believe that the optical results are good. I have seen VERY FEW pros with a 1.4x on their 80-200 zooms, and NONE with the 2x on it. Of course most pros I know own a 300. DJE
