Sports : AF speed with Canon teleconverter better than with Kenko ?

[jean_marc_liotier]

Wednesday I shot my first soccer game using a 70-200/2.8L with a Kenko Teleplus

Pro 300 AF 2x TC mounted on a borrowed 350XT (not perfect but still better than

my 300D which I found about useless for that task). I discovered that focusing

is quite a challenge - anticipation helps greatly but it is not always possible.

I was moderately content with the combo's AF performance in good light. As the

sun began to set AF got worse and out of focus images became even more frequent.

I shot at ISO1600 with AI focus in aperture priority at various apertures trying

to keep the speed around 1/1000-1/2000 while maximising DOF.

 

Considering the distances, the 580EX with a Better Beamer helped a little with

the light but the AF assist was of course ineffective. Apart from improving my

technique by practising, what can I do to better my focusing ? I have found that

prefocusing on a higher contrast subject at the same distance helps, but again

that is not always possible and a nice shiny technical silver bullet would be

welcome - well I suspect there is none but it does not just to ask...

 

So for starters would the AF speed with the Canon 2x teleconverter be better

than with Kenko ? I got the Kenko at the time when I used the 80-200/2.8L which

did not take the Canon TCs because of its protruding rear element. Now that I

have the 70-200 2.8L I'm wondering if swapping for the Canon 2x would help

improve the focusing speed. I don't really care about the image quality

improvement - improving my technique will probably yield better returns for

quite a long time before I may begin to nitpick about that limitation. I know

that I should invest in a used 20D to replace my aging 300D - that purchase is

already planned as soon as possible. Because the 70-200/2.8L is so useful on its

own and I have no economic justification for dedicated long glass, I would like

to stick with the zoom+TC solution for sports photography on the cheap. I used

it a bit for wildlife with great satisfaction but I am now finding that soccer

is quite a bit more demanding...

[dave_trayers]

Well, with the 2x your f/2.8 lens was really like a f/5.6, which is pretty slow and would be a challenge in low light for even a high end 1D series camera. I suspect that was most of your problem. Couple that with low light, and I'm not surprised you had focus issues. I also think that adding a 580EX complicated the focus issues, as the camera was trying to use the AF assist on the flash which slows it down. I don't know if you can disable the AF assist on the flash.

 

I think that a 2x converter is really too much and you should consider a 1.4x. I've had pretty good success with the 70-200 2.8L and a 1.4x at airshows, but I've also been using a 1Dmk2 which has better AF tracking performance than the 350D. I don't think the AF performance would improve with the Canon converter over the Kenko.

 

If you're going to shoot a lot of sports, you might consider finding a used 1D (the 4.15MP version). It has excellent AF performance and would work better with the lens/converter combination than the 300D or even the 20/30D. They can be had for a less than $1000US now.

[mark u]

If you use Canon's TC's AF SPEED will be reduced, but this is supposed to increase AF accuracy (unless you tape the pins that tell the camera that the TC is present).

 

http://www.bobatkins.com/photography/reviews/tcs.html

[digitmstr]

There is a real difference in AF speed between the old 80-200 and the new 70-200, for starters. The 300D is not a sports camera either.

 

You don't say what sports but, I have quite a few friends who shoot sports with the 70-200 f/2.8L IS and the 2x TC, routinely and with good AF results.

[jean_marc_liotier]

<p>

Dave Trayers said :</br>

> with the 2x your f/2.8 lens was really like a f/5.6, which is pretty slow

</p>

<p>

I agree that faster lenses would be nice, but the 300/2.8, 400/2.8, 500/4.5 and 600/4 are way over budget at the moment. For 400mm it seems that f/5.6 is the most one can obtain at a poor amateur price point. And I thought that even professionals routinely used f/4 lenses with 1.4x TC or f/2.8 with 2x TC and were often limited to the same f/5.6 as a result. Do they mostly use f/4 or f/2.8 lenses with no TC ?

</p>

<p>

> I also think that adding a 580EX complicated the focus issues, as the camera</br>

> was trying to use the AF assist on the flash which slows it down.</br>

</p>

<p>

I searched the web and found no mentions of that issue. I thought that the AF assist could do no wrong in that context. But now that you mention that I am in doubt. Has anyone else experienced that problem ?

</p>

<p>

> I don't know if you can disable the AF assist on the flash.

</p>

<p>

Yes you can : that is CF nﾰ12.

</p>

<p>

> I think that a 2x converter is really too much and you should consider a 1.4x.

</p>

<p>

1.4x is a bit short for covering a whole soccer pitch, even from the sidelines and especially when movement around the pitch is restricted. But you are right that 1.4x is much more reasonable, even quality-wise. Choices choices...

</p>

<p>

> I've had pretty good success with the 70-200 2.8L and a 1.4x at airshows

</p>

<p>

At the Paris Le Bourget air show last year I used the 80-200/2.8L with the Kenko 2x TC on a 300D with no problem : clearly defined subject on an uniform background all well lighted is pretty much the ideal case and I found even my limited hardware adequate, even though my technique was quite bad.

</p>

<p>

> If you're going to shoot a lot of sports, you might consider finding a</br>

> used 1D (the 4.15MP version). It has excellent AF performance and would</br>

> work better with the lens/converter combination than the 300D or even the 20/30D.</br>

> They can be had for a less than $1000US now.</br>

</p>

<p>

I have been toying with the idea for a while but I have been put off by high noise, banding at high iso, erratic white balance, 1.3 crop factor and absence of zoom in review mode, not to mention the 4 Mp sensor... But the bigger brighter viewfinder, faster focus, faster motor drive, weather sealing and robustness are all tempting indeed...

</p>

[jean_marc_liotier]

<p>

Giampi said :

> There is a real difference in AF speed between the</br>

> old 80-200 and the new 70-200, for starters.</br

</p>

<p>

Yes, I noticed that when I switched.

</p>

<p>

> The 300D is not a sports camera either.

</p>

<p>

... And that's an understatement. I'm aware of the problem and I'll soon allocate a budget for a replacement.

</p>

<p>

> You don't say what sports

</p>

<p>

It is a badly lit soccer game two days ago that made me aware of the problem.

</p>

[digitmstr]

wow! I can just now see your ENTIRE original post! Now it makes more sense! How strange is that?

 

I have a 70-200 as well (recent purchase) and also considering a TC for those times when you need the extra reach. Though I haven't decided which extended to get yet (both would be nice!) I know I will buy Canon because all the reviews I have seen clearly indicate it's better than the 3rd party extenders not only in terms of image quality but, reliability and AF accuracy. I am not surprised of that of course.

[digitmstr]

>>It is a badly lit soccer game two days ago that made me aware of the problem.<<

 

For that type I'd use no extenders and try to get closer to the field, if possible. If absolutely necessary, I'd use the 1.4 TC since at f/4 the AF should still work well for that sport with most bodies.

[eos 10 fan]

Jean-Marc wrote: "I shot at ISO1600 with AI focus in aperture priority..."

 

Does the XT have AI servo?

 

Doesn't AI focus wait for movement before starting AF? I'd suggest AI servo with the centre AF box. AI Servo takes a moment to get going, so half depress shutter button to let the AI servo 'warm up'.

 

--

[jean_marc_liotier]

Yes... It hit me yesterday that I chose the wrong focusing mode. Using AI focus instead of AI servo surely made the focusing on action even worse - Iﾒm quite ashamed of that mistake. Maybe I forgot to set it up properly because Iﾒm not used to do it on my 300D which does not offer that choice... As usual, discovering new hardware on the event is a truly bad idea... I guess that'll serve me as a reminder to force AI servo next time...

[jean_marc_liotier]

By the way, here is a gallery with the <a href=http://gallery.ruwenzori.net/main.php/v/sports/Football_Guinee-Cameroun/">pictures of the Guinea-Cameroon friendly soccer game</a>...<div></div>