Pre-focusing for action photography

Every year in the town where I live, they put on a motorcycle street race event. It's always over a long weekend (Labour Day here in NZ), and it's always a great day out. Especially if we get a warm spring day.

Fortunately, the weather Gods were smiling on the event this year, and the weather couldn't have been better. So I decided that I was going to attend this year and use the chance to get in a full day of photography - a very rare occasion nowadays. 

Catch me if you can. Sony A7iii with Sony G Master 100-400mm.  f/5.6 @ 1/2500, ISO 400

In my previous post I talked about scoring a bunch of Minolta lenses from a friend (thanks again Stew) to use for the event. Specifically the Minolta 100-400mm f/4.5-6.7 Apo and a Sigma 180mm f/3.5 macro. I was looking forward to using these on my also borrowed Sony a99.

I have shot this event several times over the years, with a lot of different gear, so I knew that lenses in the vicinity of 200mm would be about right if I wanted to get close to the action. In fact there are places around the track where you can get so close as to almost reach out and touch the riders as they hurtle past at 100mph. I kid you not! I, however, like to keep a slightly safer distance from the action as it unfolds. So the 100-400mm and even the 180mm macro were going to be about perfect for the whole day.

The observant among you (I'm sure that's everyone who reads this blog) will have noticed by now that the opening image in this post was not taken with the a99 in combination with the two lenses I've just discussed. It was taken with much newer gear that I also had a chance to 'play' with. More on that later.

Knee-scraping action. Sony a99 with Sigma 180mm macro. f/4 @ 1/1000th, ISO 200

It may, at first glance, seem unusual to take a macro lens to a motorsport event. Macro lenses are for close up photos of bugs and flowers - aren't they? Well yes, they are. But they can also be used as a 'normal' lens. And they also tend to be reasonably fast, and reasonably sharp. For a 180mm focal length, that's a pretty slick combination.

The one thing they maybe aren't, however, is extremely fast focusing. And neither is the 10 year old Sony a99. 6 FPS (frames per second) isn't what you would call blazingly fast. And its continuous autofocus isn't anything spectacular either. It's a fantastic landscape camera. But for fast sports action shooting - not so much.

But then again, I knew this wasn't going to be a problem. Because my favourite technique for shooting these extremely fast action sports is rather old-school. It's known as pre-focusing, and was used by all the sports photographers before this snazzy thing called autofocus tracking was invented. And it's pretty easy to do.

Bascially, just put your camera into manual focus (yes, I know, manual focusing is scary - but bear with me), 'pre-focus' on an area that you know your subject is going to move through, and then fire a burst of images as they move through the pre-focused zone. All in manual focus. Simple. And very effective.

All concentration. Sony a99 with Minolta 100-400mm Apo. f/6.3 @ 1/800th, ISO 640

There's really only one drawback using this method. You have to take a lot of images to make sure you get the sharp frame you are after. Unfortunately this dramatically increases the processing you need to go through afterwards. And I mean dramatically. For example, to get a decent 'hit rate' using this method, I took over 3500 images on the day. That's not a typo. 3500 images! And of that, around 80% are out of focus and will needed to be deleted. I'll probably end up throwing away 3000 images. But at least I'll be left with about 500 sharp ones.

Despite the tedious post-processing that this technique requires, I'm very happy with the results. If you don't have the latest and greatest gear, or a camera system that isn't optimised for fast action autofocusing, then this really should be your go-to technique.

Of course there is a better way. And it's not going to please the 'gear doesn't matter' brigade. Because for some types of photography (in fact for most types) the gear does matter. This was made abundantly clear to me later on in the afternoon.

Out in front. Sony A7iii with Sony G Master 100-400mm. f/5.6 @ 1/1600th, ISO 400

My mate Stewart turned up in the late afternoon to see how I was getting on. We chatted for a while, I told him that I was using the pro-focus technique, and he asked me if I would like to try using his Sony A7iii with Sony 100-400 G Master lens for a while?

Who am I to turn down an offer like that! So of course I said yes - thinking that I would fumble my way through, making a terrible hash of trying to follow and capture the action. OMG - was I wrong!

You can always hear the roar of the bikes approaching before you see them so you have some time to prepare. Stewart told me he had the camera set to focus tracking with a wide autofocus area, so all I needed to do was point and shoot. Yeah - right!

And yeah, he was right! As the first riders came screaming around the bend, I held the camera up to my eye, the focus points instantly locked onto the front rider, and they all lit up green. Click-click-click, the shutter fired in blazingly quick succession, and I had a series of tack-sharp images. All of them!

Need for Speed. Sony A7iii with Sony G Master 100-400mm. f/5.6 @ 1/2000th, ISO 400

I almost couldn't believe the speed and accuracy of the autofocus on the A7iii, paired with the Sony G Master 100-400mm teleophoto. It was mad, crazy, unbelievably fast. And the results were so much sharper than anything I got with the Minolta 100-400mm or Sigma 180mm. Period! I've never used anything quite this fast and accurate before. It was scary good - and exhilarating - I'm not gonna lie. 

It also happens to be over NZ$7k worth of kit! So yeah, there's that.

If you can afford it, and if you need it, then absolutely go for it. If I was doing this for a living it would be a no-brainer.

And for the rest of us mere mortals? Well, there's always the pre-focusing technique. Which does work. It just requires a lot more computer time in order to find the 'keepers' from the rest. 

Oh well. I'd better get back to post-processing then, I guess?