1Dx + 300mm 2.8 IS II + 2x Extender III

Hi all,

Going to be picking up a 2x extender to use with my 300mm 2.8 IS II tomorrow and I just wanted to check that autofocus would still work when shooting? I know that I'll be loosing 2 stops but I just wanted to double check about the autofocusing.

Thanks!

Yes it will still focus, but it might be a bit slower than the bare lens.

Yes it will slow down the autofocus, but it is a great combination, and still fast enough IMO.

Don't worry, the AF will work and it will be fast and accurate too. I use that combo a lot. The 300mm is so damn good, that the IQ loss is subtle when combined with 2X TC.

2loose wrote in post #17837612
the AF will work and it will be fast and accurate too

Is there really not much spee difference? I only ask as I might be tempted to chop in my 500 and replace with a 300ii, 1.4 and 2.0.

I have used this combo often. Focus is still fast and accurate.

nellyle wrote in post #17837648
Is there really not much spee difference? I only ask as I might be tempted to chop in my 500 and replace with a 300ii, 1.4 and 2.0.

Yes its a little bit slower with 2X TC compare to bare lens. But so far, I never have any problems in tracking BIF or any moving objects. With 1.4TC, I don't see any difference. But, you should use the Mark III version, I guess it makes a difference from the previous version.

I used to have 600mm L IS MK 1 and I found no difference in AF speed and accuracy between this lens and 300mm II + 2XTC III. That's one of the reasons I sold it.

IMHO, 300mm II + 2X TC III is the best lightweight combo for wildlife/birding.

Even with my Mk1 300 F2.8 L IS and the Canon 2 x Mk3 extender the auto focus is reasonably quick and the IQ good with my 1D4 and later 1DX. Please note though that you will be more dependant on the quality of the light. When I had the Canon 600 F4 L IS Mk1 there wasn't too much difference between it and the 300 F2.8 IS (Mk1) and the Canon 2 x Mk3 extender under good to ideal conditions. However when the light is not so good (not necessarily darker) then the native prime pulls ahead.
This certainly the most useful lens to add a 2 x extender to and will reward you with great images, though the AF will be slowed a little, but don't expect it to equal a prime under varying conditions.
Having said that if you need reasonable mobility and quality then the Canon 300 F2.8 L (any version), a couple of extenders in your pocket and a decent camera body is pretty much the top of the list in my experience/opinion.

Perfect guys! I'll be using it for sport so it's great to know that it still performs well.

nellyle wrote in post #17837648
Is there really not much spee difference? I only ask as I might be tempted to chop in my 500 and replace with a 300ii, 1.4 and 2.0.

I did this (well actually my 500 was stolen) and I'm glad I did.

- I reckon my 300II with the 2xIII is actually sharper than my 500IS Mk1 was bare**.
- The reduction in focusing speed with the MkIII TCs is much less than was the case with the MkII TCs. It's plenty fast enough for BIF, etc.
- I can hand-hold it all day.
- It packs into a much smaller bag so less hassles at the airport.

**I'm not a fan of DxOmark (so make of the following what you will) but the 300II is the sharpest lens in their database at a perceived 45MP. In comparison the 500II only scores 31MP so there is quite a bit of headroom.

Thanks Scott, it looks like it's worth looking at a bit closer!

nellyle wrote in post #17837648
Is there really not much spee difference? I only ask as I might be tempted to chop in my 500 and replace with a 300ii, 1.4 and 2.0.

While its not the same lens combo, I bought the 1.4xIII to use with a 70-200 2.8 II. I was worried as I had read many people had issues with AF speed and all that. I cannot notice a difference at all. I would not hesitate to do it again.

Some of the pictures in this album are taken with the combination 1DX, EF 300 mm f/2.8L IS II USM and EF extender 2X III. You can see which they are by checking the shooting information. If the focal length is listed as 600 mm, it's actually this combination that was used.
The AF speed slows down when using an extender, but that's kind of natural, and not too much to be afraid of. It's not really focusing speed that slows down, it's the rotation speed of the focusing ring. Since a 1.4X extender will give you only half of the view, rotation speed will go down to 50%. When using a 2X extender, you only cover one quarter of the image you otherwise would, and focusing speed is reduced to 25%. But due to the magnification, the apparent effect of rotating the focusing ring is greater than normal, so this kind of cancels itself out.
I've not seen it as an issue when I've used this combination. I need long telephoto lenses too seldom to motivate an EF 600 mm f/4L IS II USM or similar.

How does the 300 i is compare to the ii?

Sorry for thread hijack!

nellyle wrote in post #17840358
How does the 300 i is compare to the ii?

Sorry for thread hijack!

Used to have it before I upgraded it. It was a superb lens and I didnt notice any difference in AF or IQ. The only reasons I upgraded were because of the weight and the new IS mode 3.