70-200 f2.8 with 2x teleconverter on a crop camera

Going on a cruise and going parasailing, so I need a long lens to take pictures from the boat of my wife, daughter and parents. Was going to grab the 100-400 for this, but had the thought of getting the 70-200 2.8 with a 2x converter. Lighting will be good so loosing 2 stops does not worry me. Just wanna make sure my 60d will still work with this set up. By doing this I also then get the 70-200 which would see more use then the 100-400 which would only come out for this one excursion.

That combo should be fine...it is effectively 140-400mm f/5.6, so the camera AF will still function.

You get the AOV on your 60D which is equivalent to 224mm-640mm mounted on FF body

Autofocus with the 2× extender (@ f/5.6) is slower than without (@ f/2.8 of course) on a 60D.
I don't have a 100-400 so I can't compare to autofocus speed at f/5.6 on a 100-400.

Littlejon Dsgn wrote in post #18264530
Going on a cruise and going parasailing, so I need a long lens to take pictures from the boat of my wife, daughter and parents. Was going to grab the 100-400 for this, but had the thought of getting the 70-200 2.8 with a 2x converter. Lighting will be good so loosing 2 stops does not worry me. Just wanna make sure my 60d will still work with this set up. By doing this I also then get the 70-200 which would see more use then the 100-400 which would only come out for this one excursion.

Does "...getting the 70-200 2.8 with a 2x converter" mean a purchase?

Having done something similar, I suggest you rent the combination. It isn't as useful as you might think and taking pictures "from the boat of my wife, daughter and parents" sounds like you may have motion issues forcing you into the higher shutter speeds and or higher ISO to get higher shutter speeds.

Just make sure you get the 70-200/2.8 IS II, the old version does not work very well with the 2x.

I'd go with the 100-400mm.

2X T-C on a zoom lens tends to = disappointment.

What about the sigma or tamron 150-600? Cheaper and possibly more versatile.

Seems that folks are recommending long lenses, which is what OP was trying to get away from!
"By doing this I also then get the 70-200 which would see more use then the 100-400 which would only come out for this one excursion."

CyberDyneSystems wrote in post #18264565
2X T-C on a zoom lens tends to = disappointment.

Is the 2X TC different than stacking two 1.4X TC? I have put two stacked (one Canon + one Kenko) and the results were pretty impressive! Admittedly mine was 70-200 f/4 lens rather than f/2.8 lens. In this comparison, camera position was adjusted to have same filling of frame with subject for comparison of quality.

Stacked TC (1.4X + 1.4X):

The older 70-200 isn't wonderful with 2x teleconverters, the IQ isn't great, but with the MKII the results will rival the 100-400 (1st edition). Purportedly the 70-200 non IS is supposed to be better than the IS version, so that might help.

That being said, you will need to raise your ISO to help with the exposure obviously, but also to bump up your shutter speed a bit, and also close down your aperture to f7.1 or f8 to help with any IQ loss.

However the results are pretty good. Here is the non-2x view with the 7D2, and then with my ancient Kenko 2x that still works with all my cameras vs the new Kenkos that are all messed up.

Here is a partial crop of the 2x shot... Not outstanding, but in a pinch and if you are looking more to capture memories in the form of nice images, it would work. Get the Canon MKIII 2x and the results would be much better.

Thank you everyone for the help, if I go this way I will make sure to get the mark 2 version. I have used the 150-600 and its a BIG lens, way more then I want to pack and carry for this one set of photos. A dedicated wild life trip to Banff, that was another story. Its honestly between the 70-200 with extension of the 100-400 and the place I normally rent from only has 1.4's so that might be the deciding factor. Also with regards to shutter speeds and high ISO's. I dont think that will be a problem, 11:00 daylight in the Caribbean. Even if I had to go to ISO 400 im sure I would be just fine.

Wilt wrote in post #18264579
Is the 2X TC different than stacking two 1.4X TC? I have put two stacked (one Canon + one Kenko) and the results were pretty impressive! Admittedly mine was 70-200 f/4 lens rather than f/2.8 lens. In this comparison, camera position was adjusted to have same filling of frame with subject for comparison of quality.
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Uhm.. your sample images look oversharpened, and JPEG artifacts prevent any meaningful analysis.
A fact people often overlook, is that still test shots give much better results than actual shots in the field. AF speed and accuracy being one of the most important factor.

That appearance of 'oversharpening' is merely the sun's light striking the fuzzy edges and surfaces of leaves on an artificial flower. The same light is striking a cobweb on the no-TC shot as well.

Littlejon Dsgn wrote in post #18264638
Also with regards to shutter speeds and high ISO's. I dont think that will be a problem, 11:00 daylight in the Caribbean. Even if I had to go to ISO 400 im sure I would be just fine.

In the Caribbean, sun goes down fast. I predict you will use higher than ISO 400, and being able to shoot f/2.8 will help a lot. Get the 70-200/2.8 IS II.

This is why I ran outside for this test and shot the noisy "keep me awake at night" geese that frequent our pond this time of year. I know everyone wants quieter shutter sounds from Canon, but I actually wish sometimes the shutter sounded like a gunshot, it might scare them off.

Unfortunately, I am using a 10 year old Kenko 2x TC, and I know they have improved since. However I have tried a couple of DGX versions and they cause 2 stop overexposures on my 7D2 and 5D4, and with certain lenses like the Sigma 150-600, it locks up the cameras. So I keep my old Kenko, it works with every Canon model I have or do own.