If I use a Canon 2X teleconverter on my 2.8 70-200L will the minimum fstop at 200mm still be f5.6?

You are correct. I have used my Canon 2.8 70-200 IS L lens with both the 1.4x and 2x Canon teleconverters. 1.4x cost you 1 stop and the 2x costs you 2 stops.

I also own the Canon 100-400 4.5-5.6 L IS lens and through some basic tests, I came to the conclusion that the 100-400 is sharper at most apertures than the 70-200 with the 2x extender.

I hope that this helps.

Bud James

Yes, I was aware of the reduction in image quality with the 2x, but can't some of that be made up with higher apertures, such as f11-16? I'm still contemplating the 1.4 which would give me 280mm lens at f4, but with better image quality.

No. The minimum f-stop with a 2× TC will be f/64. But the maximum f-stop will be f/5.6 indeed.



Yes, it can ... to a degree. But keep in mind that from f/11 on (with APS-C format) or from f/16 on (with 35-mm format) you will start to see diffraction effects. So all in all, you'd be very restricted as far as image quality and choice of apertures goes. Of course, that doesn't mean image quality would be bad or even unusable ... but it would clearly be below the level you're used to from this lens without TC.



In my opinion, that'd be the wiser choice! You'd sacrifice some telephoto reach in exchange for a better and more versatile lens. The loss of image quality with a 1.4× TC is considerably less than with a 2× TC. If you need the 300 - 400 mm range badly then better buy a lens covering it natively.

-- Olaf

I use the 1.4x on my 70-200 all the time. It's a terrific combo -- still has good focusing speed and excellent sharpness. (Well, excellent for p-j work, handheld fast action stuff, anyway.)

The 2x works, but the quality reduction becomes apparent pretty quickly.

I meant maximum aperture. Sorry. Well, true, a 100-400 would be much better, but I'm probably only going to use the tele for macro shots using my 200mm (semi macro) since the tele doesn't affect the minimum focus range, and then people photography. I have a extension tube for my 24-70, and it's great, but getting 1" away from nature sometimes is not advisable. So the 400mm with a focusing distance of 4 feet would be pretty good for close up shots. I won't be using it for anything else I don't think. I wish I could simply rent the tele for a while to see if I like it or not, but where I live I'd be lucky to rent a paper bag, photography speaking.

Well, I'm leaning hard toward the 1.4 then.

Agreed. I have the 2x, and after using it and reviewing my photos, it's never been out of my bag again.

Actually, it's in a drawer. I can't stand the effects. The 1.4x is fine. Good, even.

I have the 1.4X and 2X and used both with my 70-200 f/2.8. The 1.4X produces a nice image. The 2X can produce a fair image but honestly its what drove me to buy the 100-400. The 100-400 is slow but a really nice image. I still lust after the 400 f/2.8 but that will have to wait for when I hit the lottery.

Thanks for those who responded. I bought the 1.4 and hope I'm not disappointed with it. I'll get 80mm more reach without sacrificing minimum focusing distance. That may be good for close ups of small objects too.