70-200 f2.8II + 2xIII on 7D vs 300 f4 + 2xIII on 5D3

[danski0224]

Those two lenses utilize different aspects of the AF system- one lens is f2.8 and the other is f4, before the 2x converter is used.

The 70-200 f2.8 seems to focus much faster than the 300 f4. I suspect that part of it is the speed of the USM motor and the other part is the AF sensor type that is used.

Adding the 2xIII to the 300 f4 really knocks down the AF speed.

I think you will be disappointed in the 5DIII - 300 f4 - 2xIII combo just considering focus speed- because it won't, until the 5DIII firmware update is released.

I would suggest renting that combination and trying it before buying it, after the 5DIII firmware update is released. I think you are better off keeping the 70-200 f2.8 II, 2xIII and 7D if the big white lenses are not justifiable. 

The 300 f4 and 2xIII will AF on a 1 series body.

Edit: even adding the 1.4x to the 300 f4 makes a very noticeable reduction in AF speed.

[rs]

Here's the 300/4 + 2x TC on FF vs a 70-200 + 2x TC on crop:

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=111&Camera=453&Sample=0&FLI=4&API=2&LensComp=687&CameraComp=736&SampleComp=0&FLIComp=5&APIComp=0

There's really not much in it. The 100-400 with a 1.4x TC seems to be marginally better than a 300/4 with a 2x TC, and it gives you the option to zoom:

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=113&Camera=453&Sample=0&FLI=10&API=0&LensComp=111&CameraComp=453&SampleComp=0&FLIComp=4&APIComp=2

Usually you need a shutter speed of at least 1/500th of a sec with sprint kayaking to provide enough subject motion freezing while still having a little movement in the water droplets. Unless you've got great light, an f8 lens combo that needs stopping down to f11 or so will require a very high ISO to get those shutter speeds.

Without resorting to a supertele such as the 300/2.8 with the 2x TC or preferably the 600/4, you're not going to see any significant improvement over your current setup. A ~600mm f8 lens on a 5D3 is going to give similar DoF, sharpness and reach to your 70-200, 2x and 7D setup.

Are there any other options such as getting in a safety boat (as long as its just floating nearby rather than following them down the course), or are there any pontoons there such as at the start, finish or at the 200/250 markers? Even sitting in a TC2 might do the trick. If you have the option to somehow get up close and fill the frame with the bare 70-200, the results will be much better than what is possible with a 600/4 from the far end of the course.

[K-amps]

7DII?  Does anyone really think that it would match the 5DIII IQ and iso, plus be faster? 

Santa Claus
the Easter bunny
the tooth fairy
bigfoot
the lochness monster
and all honest politicians do

 

 

[Halfrack]

Canon SX50?  There comes a time when you either have to pony up to the bigger toys, or make trade-offs.  SX50 should have all the reach you want (24-1200mm equivalent).

EOS-M isn't the answer - same crop factor.  Nikon's N/J mirrorless may be an answer, but different glass involved.  F8 manual focus lens with adapter?

[East Wind Photography]

I've given up on the 7D.  I now use the 5DIII exclusively.  Much better IQ even when cropped.  Less noise and better AF system is a plus.

Rent one of the bodies you dont have and see how it works for you with the 70-200II and 2XIII.  Then you will know if you need the 300 f/4.  There is also a 400 f5.6 which is reasonable too.

[bluenoser1993]

Thanks rs for the link.  I'm confused because I've been on that site and wasn't able to sellect the 60D for the 70-200 2.8 IS II for some reason.  Don't know if it was due to a bad connection that night or what, but was only able to find a few EF lenses that had the 60D option.

Any way, very informative and it makes me want the 5DIII even more now.  I've always been blown away by the sharpness of the 70-200 on the 7D and can't believe that it can be that much better!  I love it so much I'd say it slots in at number 6 - right behind my wife and 4 kids!  Some days it gets a little higher up the list

I really enjoy night time photography - long exposure and hand held - so that is the real motive of the body upgrade.  I also crave extreme clarity in the architectural details of the buildings I shoot in my travels with work.  I understand that the long range shots on the lake won't be great by many standards, using the gear I have, but I just wanted to be sure there was an economical (relative I know) sollution to use with FF body that wouldn't be a down grade to my current "long lens" arrangement.

Thanks to the great responses here, I am comfortable with my plan of going FF.  Now I just need a little more price drop and a good sale on top of that and I should be able to make my wife comfortable with the plan too!  Luckily the 7D is a fine body (except for ISO) and I know the 5DIII will last me many years, so I don't mind waiting a while for the price.

I've been reading this forum for quite a while, but never posted a question before.  Thanks so much to everyone that took the time.  All the responses were helpful.

[wickidwombat]

Here are some 100% crops top 2 are 300 +2x TC on 5dmk3 wide open then 1 stop down
second 2 are the eos M with 70-200 +2x TC wide open and 1 stop down