I wouldn’t bother, personally. I have the Canon 1.4x and the 2x, and the 2x in particular is worthless. It adds so much aberration to the image that there is no advantage in quality versus just cropping the un-extended image and blowing it up. But above and beyond that the equivalent of three full stops of light loss means that you stand a good chance of not being able to make the shot at all.
So you can basically forget about taking pictures of birds with it around sunrise or sunset, or on cloudy days, or under any kind of tree cover. It’s a good thing birds never show up in any of those conditions…
Get an extender or two. I have a 2x: it’s small, not too expensive, and in decent light it works great!
I wouldn’t bother, personally. I have the Canon 1.4x and the 2x, and the 2x in particular is worthless. It adds so much aberration to the image that there is no advantage in quality versus just cropping the un-extended image and blowing it up. But above and beyond that the equivalent of three full stops of light loss means that you stand a good chance of not being able to make the shot at all.
So you can basically forget about taking pictures of birds with it around sunrise or sunset, or on cloudy days, or under any kind of tree cover. It’s a good thing birds never show up in any of those conditions…
So I gave up on it.
Huh, what lenses were you using it with?
The RF 100-400, and the RF 200-800.