I see people taking photo's of bugs all the time, and until now didn't realize how difficult that can be, the wind was my problem yesterday, getting this guy in focus was a real trick, it's web was strung between two evergreen bushes about three feet apart. the slightest breeze threw the focus out. Had to take a dozen hoping to get one of two that were in focus, this is the best I could get,
no post work just a little cropping

Canon 6D
Tamron 150-600mm (on tripod) @ 12 ft
Remote flash

and a little luck..

cm, I know you're new here, so to you, so are all of us.
Nobody looks at 600mm lenses cause they shoot things that don't move!
I'm a hard-core FF shooter, but I also do a lot of sports.
My next camera was easily going to be the 5lll.
BUT, I've also been looking at the new 7ll. That darn thing is almost as much camera as the 1dx, with possibly a more sophisticated focus system for 1/3 the price!!
In sports/action/birds etc., mp count oftentimes takes a backseat to what is actually possible to capture. I'll admit the possibilities presented by 10 fps and 61 cross focus points could well be the difference between landing a killer shot and just wishing, if only it was in focus. cm, a billion mp won't help you if you don't get the shot!! Mp's is a luxury, not a necessity.
Personnally, I'm toying with the idea of leaving FF just because of the new 7ll. Plus, the idea that a 600mm is suddenly a 960 with no cropping can't be ignored, when a bird is only the size of a golfball and it's 20 feet away.
cm, don't rule out getting an old 7dl for $500-$600 just to get your feet wet then decide between on a 7ll or a 5lll.
For me, the lines have suddenly become very blurred! :lol:
cm, if you click on my name, then on my created topics, you'll find a few of my shots. That will give you an idea where I'm coming from.
As the proof is always in the pudding!! ;-)
SS

I totally agree with wanting to put the extra $ into lenses. I think sensor size is a bigger factor than mp count, as the 5D Mark III has a full frame sensor and the 1D Mark IV has a APS-H (1.3x smaller) sensor. The 5D Mark III does not really have "a high mp count", these days 16-24mp is "normal". :-)

At 22.3mp, the 5D Mark III has less than 20% more linear resolution than the 16mp 1D Mark IV. That's basically going from a 20x30" print to a 24x36" print. Yes, it's better, but if you have either print on the wall few people are going to notice which size it is.