Extenders, are they worth it?

I'm in a pickle, I run a 300f/2.8 L IS and a 70-200f/2.8 L IS ii, and I have a 1dx and a 7d2, mostly shoot field sports, Rugby, Soccer, Hockey and I want to make the most out of the 1dx but I get much better reach out of the 7d2 obviously due to the 1.6x crop factor.

Which extender would best best value if any? 1.4x iii, 1.4x ii, 2.0x iii or 2.0x ii

I can't afford a 400f 2.8 so that's out of the question

You tell us.

Not trying to be smart but that's reality. Some people are happy with TCs while others are not, even for identical lens and body combinations.
The obvious thing to do is get a 1.4 and try it. There's very little difference between the 1.4 II and III with your equipment.
1.4 III is better long term as it provides advantages with some lenses and some bodies.
100-400 II, 200-400, all V2 Super teles with recent bodies. Advantages are more or all AF points and or faster AF.
80D, 5D4 and 1DX2 bodies have some or all advantages.

I doubt you will find the 2X worthwhile for sports.

I agree with Choderboy. If you're going to buy a TC, stick to the Canon 1.4X II or III. Avoid the 2Xs all together. Here is a review of TCs. It is not in English, but the numbers tell the story, not the text.

http://www.traumfliege​r.de …r/overview.php#​kenko14dgx

Summary:
For the center circle of the frame, the Canon 1.4X II is the sharpest TC available. If you count the periphery (of full frame image), the Canon 1.4X III is better overall. If you are using long glass, and a TC, you are likely cropping the edges anyway. Optically, that makes version II the best you can get.

Version III offers some advantage when used with some version II telephoto (primes & zooms) lenses: better, as in faster more accurate auto-focusing.

With the gear you already have, I'd suggest version 1.4X II, 300mm lens, and 7D2. The only reasonable alternative is 1.4X II, 300mm lens, 1DX, and crop. In the end, there is probably little difference. Real solution: 600mm f/4L IS USM II. $$$$!!!!

I've a 1.4x mk I that gets used with a 70-200mm f/2.8 IS quite often during the kids soccer season, also a 2x mk II that has been used exactly twice with a 300mm f/2.8
happy for you to borrow either/both for a couple of weeks...

You can also rent tele-converters, lenses, camera bodies, flash, etc. online

https://www.lensrental​s.com …rue&q=&sort_by=​popularity

https://www.borrowlens​es.com …ct.do?code=Cano​n_1.4x_III

https://www.borrowlens​es.com …anon_2x_III_Tel​econverter

Inspeqtor wrote in post #18583391
You can also rent tele-converters, lenses, camera bodies, flash, etc. online

https://www.lensrental​s.com …rue&q=&sort_by=​popularity

https://www.borrowlens​es.com …ct.do?code=Cano​n_1.4x_III

https://www.borrowlens​es.com …anon_2x_III_Tel​econverter

Location: New Zealand.

300+1.4x on the 1D and the zoom on the 7D. 300 will benefit from the better focusing system and bigger battery

bildeb0rg wrote in post #18583413
300+1.4x on the 1D and the zoom on the 7D. 300 will benefit from the better focusing system and bigger battery

Quite possibly so, but at the risk of running out of resolution to crop. 7D2/1.4x/300 puts way more pixels on target. The question is 'need'.

Bassat wrote in post #18583361
I agree with Choderboy. If you're going to buy a TC, stick to the Canon 1.4X II or III. Avoid the 2Xs all together. Here is a review of TCs. It is not in English, but the numbers tell the story, not the text.

http://www.traumfliege​r.de …r/overview.php#​kenko14dgx

Actually the 2x work pretty well in some situations.

This is with the Kenko 2x on a Sigma lens.
https://photos.smugmug​.com …efb128/X5/5P1B9​656-X5.jpg

I also now have the Canon 2x III, and others have reported it works well with some of Canon's newest II glass where IQ is actually pretty darn good.

Again, though, in most situations a 2x is going to cause some issue with missed focus, possibly noticeable IQ loss, but in good lighting, I feel a 2x on a lens that won't cause the camera to not AF, it certainly has merit. Not in the situation of the OP though, a 1.4xII or 1.4xIII would be a better choice.

I also reviewed the YongNuo 2x MKIII Canon knockoff, and I felt, as did others, that the best use of that would be one dedicated to a lens like the 70-200 2.8. This is 50% of the Canon cost, but comes with a couple of hassles that can be worked around.

https://photography-on-the.net …/showthread.php​?t=1487269

TS, I'll defer to your greater experience with 2X, and with better glass. I used a 2X II on 100-400Lc; no AF didn't bother me. The IQ did. Also on the 200 2.8L II. IQ suffered noticeably, as did AF. Camera was 80D.

Choderboy wrote in post #18583407

Inspeqtor wrote in post #18583391
You can also rent tele-converters, lenses, camera bodies, flash, etc. online

https://www.lensrental​s.com …rue&q=&sort_by=​popularity

https://www.borrowlens​es.com …ct.do?code=Cano​n_1.4x_III

https://www.borrowlens​es.com …anon_2x_III_Tel​econverter

Location: New Zealand.

Woops... sorry

Unfortunately your 1Dx paired with a Canon 1. 4 TC will only allow you to shoot at F/8, center focus point only. If I had your set-up, I'd stick with the 7d.

James P wrote in post #18583442
Unfortunately your 1Dx paired with a Canon 1. 4 TC will only allow you to shoot at F/8, center focus point only. If I had your set-up, I'd stick with the 7d.

Wrong-O!

With both listed lenses, either/both cameras will be at f/4 with a 1.4X, and f/5.6 with a 2.0X. All AF points will remain available on both bodies.

The 1.4x will work well with the 70-200 with relatively little loss in quality (especially if you stop down a bit).

The 2x is much bigger hit in quality and AF speed; though I've had decent results with it on a 5D3 and 5D4 for wildlife and motorsports shooting.

I'd suggest the vIII for the 2x, though I believe the 1.4x is less critical.

I've not used the 300L, but I'd suspect it'll be at least as good (or better) with the TCs.

Canon's newest extenders are great. Obviously not in every situation, but like any tool they can be handy. I have both the 1.4X & 2X and use the 1.4X the most.

With today's cameras f/4 is still pretty fast and the autofocus is quite responsive.