Sigma 120-300 for sports

[Fredo]

G'day people,
This post is aimed towards people with experience in using the Sigma AF 120-300mm EX DG mainly for sports or fast moving subjects. It's mated to the Canon 30D.

I have probably taken over 1200 photos so far - 80% surfing, 10% car racing and 10% footy and hockey - which I shot today!!!

My concern is with the focusing and the number of "keeper" images I get out of a normal shoot of say 200 photos. I'd guess that roughly 60% are keepers that are predominantly tack sharp and can't be faulted. However, in the balance of photos they are out of focus.

My main camera settings are as follows -
Av mode
100 ISO
f/4.0 (1.4x Sigma DG tele-converter attached)
Evaluative Metering
9-point AF
AI Servo
High Speed Drive Mode
always use a mono-pod

I guess i'm wondering why approx. 40% of photos are soft and out of focus!!! I always shoot with the sun on my back or not at all, so light is never a problem.

I tried centre-point focusing but with very limited success - 9-point seems the go!!!

As I state, the keepers are some of the best images i've shot and rival anything i've seen for sharpness but just when you need the lens to perform and when you think you've got a great image, you get home and check it out on the computer and it comes out soft or distinctly out of focus!!!

To me that is the most frustrating and gut-wrenching feeling when you see what could be a brilliant image rendered useless by poor focusing - and probably no fault of your own but the equipment!!!

Is my problem the lens or the camera??? Is there some way of calibrating the two so they end up being that "match made in heaven"??? Who do I send it to - Canon or Sigma???

If anyone has this setup or experience with this specific lens I would love to hear your opinions.

Thanks in advance...

FREDO

[grego]

Using all 9 is always going ot give you a lot percentage of keepers.

Aside It's all about knowing the sport. I just shot tennis with my Sigma and it held up greatly. Some examples woudl be best though.

[Bill S]

At f4 with the 1.4 the nine point may hurt you. The camera may select a focus point other then the subject and the DOF puts the subject OOF. I have also found that I must really work on my technique at 300mm or with the 1.4. Any slight move or jerk will also cause motion blur or OOF. The focus is fast and if you move and the focus starts to adjust it can cause problems.

Can you show us samples of the OOF shots.

[Simon Harrison]

Some of your problem could be with using all nine AF points. I shoot a lot of motorsports, and always select the AF point (not always the centre one) that I want the camera to use so that I'm in control. In my experience, most sports shooters will select the AF point they want to use. Leaving it up to the camera means that it could decide to change it's point of focus just at the time that you don't want it to.

If I were you, I would persevere with single focus point AF.

Also some of the sports your shooting (probably all of them with the exception of the motorsport) involve erractic, and to an extent unpredictable movement of yor subject. Modern AF is good but it is not infalable. You need to give time for the AF system to lock on and begin tracking (usually a second or so) before firing the shutter. Also, don't forget that your first shot will be in release priority i.e. the camera will allow the shutter to fire even if it hasn't achieved focus lock. This makes tracking your subject even more important.

Cheers,

Simon.

[GyRob]

i to think centre point only or 1 of the others is the way to go i shoot a mk2 but only use all point's for birds in flight all point's might be good but is far from perfect .
Rob.

[lungdoc]

Could you go higher ISO and smaller aperture to make DOF less critical? I find it hard to tell much difference between ISO 100-400 in most cases. You would gain DOF for focus, though perhaps at the expense of not isolating subject from background, although at 300mm F8 there's still only about 10feet in focus, versus 5 at F4.

[GSH]

As others have stated, the majority of your problem is almost certainly because you're letting the camera choose the focus point.

Stick to single point focus (preferably centre) and your keeper rate will shoot up, even with the 1.4xTC attached. Experiment with the other focus points too, but always use 1 focus point and never let the camera do the selecting.

The 120-300 on a 20 or 30D is a very capable set-up indeed, there's a few of us on here using it and you will rarely see any complaints :)

You might want to try switching to Shutter-Priority (TV mode) and using the 30D's improved ISO control to get the aperture you want too.

[blackviolet]

use a single AF spot. if you are shooting in portrait orientation, choose a spot near the eyes. i still recommend AI-servo and AV mode. shooting surfing can be difficult as there is always lots of contrast for the camera to focus on. as you keep shooting, you'll get smoother at your panning to keep the AF spot on the subject - so the AI will work better, too. i almost pulled the trigger on the weekend and picked up the 120-300 at Yodobashi, but they only have Japan warranty. shipping it from B&H is too much so i'll probably pick it up locally. i have used one a few times and found it to be a very capable sports lens.

[dmwierz]

I have used the 120-300 for tens of thousands of action shots with my 20D, and the suggestion to use center point is what I would also say. Don't worry about DOF.

One other thing, don't zoom after you have locked focus. This lens is not parfocal. In other words, zoom THEN lock focus, as opposed to many of the Canon L lenses. It took me a few games to learn this, and it made a big difference in the number of keepers I get.

Also, take try taking off the TC, and this might improve AF somewhat, although I use the Sigma 1.4 in daylight and have had a lot of success.

Dennis
http://www.pbase.com/dmwierz45/sports_shots

[DavidEB]

maybe not the lens' fault. see >>>this<<< (http://photography-on-the.net/forum/showthread.php?t=114832) and >>>this<<< (http://photography-on-the.net/forum/showthread.php?t=117521). that was with 20D + 70-200f2.8 or 135f2. For me the solution was to get a 1D.

[Dellboy]

Try this link; http://www.photography-on-the.net/forum/showthread.php?t=116971

It is writen by one of the best sports togs that fequent this forum ( IMO ). Many of the issues brought up so far on this thread are addressed already and you can ask him a question or two if you'r still having problems.

Check out some of his shots and you'll know he must have a trick or two worth knowing - he is also very generous in sharing his knowledge.

Hope this helps you as much as it did me, Good luck, Dellboy.