Fast Action Focus

SDJames · June 26, 2007

I have two recent experiences where I can't seem to maintain focus for a sequence of shots:help . Yes, I generally get a decent shot out of the series, but want to be sure I'm on top of my game. The two examples are kite surfing and flag football. I have tried both Servo and AI focus with only using the center AF point....the action starts, I start shooting...sometimes at full 5fps, sometimes with a slight lift of the shutter to then burst again.

Flag football is usually with the 70-200 f2.8 using shutter-priority at 1000 handheld. Here, I typically shoot AI focus due to the chaos.
Kite surfing was with the 400 f5.6 using shutter-priority at 1250 on a monopod. Here is where I've tried Servo due to the lack of clutter in the shot.

Do I simply need to practice keeping the AF point on subject? Of course, I realize the 1-series has the 45-point, more intelligent focus system... but that's another story:dunno . There must be a better way...keeping that dot on my subject can be tricky.

Tips are greatly appreciated.

donek · June 26, 2007

SDJames wrote:

I have two recent experiences where I can't seem to maintain focus for a sequence of shots:help . Yes, I generally get a decent shot out of the series, but want to be sure I'm on top of my game. The two examples are kite surfing and flag football. I have tried both Servo and AI focus with only using the center AF point....the action starts, I start shooting...sometimes at full 5fps, sometimes with a slight lift of the shutter to then burst again.

Flag football is usually with the 70-200 f2.8 using shutter-priority at 1000 handheld. Here, I typically shoot AI focus due to the chaos.
Kite surfing was with the 400 f5.6 using shutter-priority at 1250 on a monopod. Here is where I've tried Servo due to the lack of clutter in the shot.

Do I simply need to practice keeping the AF point on subject? Of course, I realize the 1-series has the 45-point, more intelligent focus system... but that's another story . There must be a better way...keeping that dot on my subject can be tricky.

Tips are greatly appreciated.

Harryb posted this link on the wildlife section: http://www.nikonians.org/html/resources/nikon_articles/body/multi-cam2000_af/index.html

It is specific to the Nikon focusing system, but may be helpful in further understanding how the different focus settings work on the camera. There is likely something similar for Canon, but I shoot Nikon and haven't paid enough attention. If you were shooting Nikon, I'd have some recomendations of things to try for you, but know nothing about Canon's system. Hopefully that will give you a good starting point. Maybe you can google some of the terms in that article, but add Canon to the search terms.

gsgary · June 26, 2007

Have you tried back button focus it works a treat on my 10D and 1D, got more keeper when i started using it on the 10D

sirsloop · June 26, 2007

I just get in the zone and snap off single shots, AI servo, center focus point, Av usually set around 5.6 (iso to get me bare minimum 1/500th, 1/1000th+ is ideal) on my 70-200/2.8L. If you can believe it, I went out shooting on sunday and had a ~90% keeper rate out of over 3000 photos taken. I think the biggest problem with shooting high FPS is the mirror is up so after the first shot you have no idea where the focus is at. Also, if you use AI focus you are not guranteed focus on your subject. The camera may decide that something else looks focus friendly and will shift on you.

SDJames · June 26, 2007

Awesome! Thanks for the tips.

gsgary wrote:

Have you tried back button focus...

YES, that's what I was looking for!

Time for practice now. I'm sure it will drive me nuts for a couple of shoots, but sounds awesome. Thanks.

sirsloop wrote:

I just get in the zone and snap off single shots, AI servo, center focus point, Av usually set around 5.6 (iso to get me bare minimum 1/500th, 1/1000th+ is ideal)...

Yep, that's been my most reliable setup.

I also searched for 'back button focus' here and came across an article that cmason found and shared that describes how the focusing works in detail and mentions BBF.

You guys rock.

Dbl · June 26, 2007

As gsgary suggested I think you should try moving the focus to your back * button. A large majority of sports shooters use this method, it may or may not work for you, but there is only one way to find out...try it.

Splitting your focus from your main shutter button will allow you to start tracking the subject and give your focus a chance to "get up to speed" before you start shooting. It also allows you to freeze the focus by letting up on the back * button. Works great for re-framing a shot as in baseball. This will allow you to stay in AI Servo the vast majority of the time.

I am curious why you shoot flag football in Tv mode? You have a 70-200/2.8, I would be in Av at 2.8 or 4.0 till your focus tracking improves and use your ISO to keep your shutter speeds up as the light changes. Minimizing your backgrounds with a shallow DOF will make your subjects pop off the photo.

Tracking is not an easy thing to do, it really does take a lot of practice. Stay with it and concentrate on keeping your center point on the subject and it will get better. Good luck and keep shooting.

Edit: I see I was writing this as you responded. Glad to see you give the * button a try.

gsgary · June 26, 2007

Not sure what flag football is but when i shoot rugby or any sport i always shoot on manual wide open

2whlrcr · June 26, 2007

Boy, I've got questions here too. I've read the article on Canon's AI Servo and it's a little confusing for my feeble mind.

I've got a 30D and use my 70-200 2.8 IS and 17-55 2.8 IS as my primary lenses. I shoot a lot of motorcyle action that is coming towards me.

I get about 10% OOF shots and another 10-20% soft focus shots. So my capture rate is about 70-75%. Maybe that's the best I can expect?

I've tried AI Servo and AI Focus. I've also tried tracking the subject with the shutter half depressed. I've also tried just shooting with a single push of the shutter. My results all seem to be about the same. I don't use a burst mode. I like to take single shots, but sometimes in rapid succession. I'm always shooting at F2.8-4.0 to keep a SDoF.

Another problem I have is I don't necessarily want my main subject centered in the shot. I know this really throws the AI out of whack. I hate to shoot wide and then crop later, because I like to keep as shallow depth of field as possible.

So anyway, I've settled on AI Servo and using a single push of the shutter. Is there a better way to do this, for more consistent focus on subjects moving towards the camera? One last note, If I suspect action at a certain spot, I will prefocus on that area. But half the time my action is taking place somewhere other than the prefocused spot.

Comments?

SDJames · June 26, 2007

gsgary wrote:

Not sure what flag football is...

It's low impact, beginner's football...

...you try to grab the velcro flags instead of tackling.
gsgary & Dbl...Good point with Av vs anything else...my better pics are with the shallow DOF. Thanks. I was too busy experimenting to focus on the best pics.

2whlrcr, to paraphrase the article, you may be in a situation where the action if too fast for the camera/lens to compensate if it's coming straight at you. If you can somehow alter your position so that you get a more side angle, it may help. I'm no expert, though.

BTW, I just got back to my camera and I like the way BBF feels...I just need to get used to it!

cecilc · June 27, 2007

2whlrcr wrote:

Another problem I have is I don't necessarily want my main subject centered in the shot. I know this really throws the AI out of whack.

The only way that you're going to be able to do that is to separate the focus from the shutter button. That's party the reason for shifting focus to the "back" button ...

gsgary · June 27, 2007

SDJames wrote:

It's low impact, beginner's football...

...you try to grab the velcro flags instead of tackling.
gsgary & Dbl...Good point with Av vs anything else...my better pics are with the shallow DOF. Thanks. I was too busy experimenting to focus on the best pics.

2whlrcr, to paraphrase the article, you may be in a situation where the action if too fast for the camera/lens to compensate if it's coming straight at you. If you can somehow alter your position so that you get a more side angle, it may help. I'm no expert, though.

BTW, I just got back to my camera and I like the way BBF feels...I just need to get used to it!

You mean American football

we have the same game with rugby

RevLinePhoto · June 28, 2007

I have a 30D in the mail right now and was wondering is it posible to set up back button fucusing?

Thanks,
Ryan

rwells · June 28, 2007

Use the back button for focus...

Very Important

> Make sure you keep the center focus point on a high contrast edge (on your subject) if at all possible.

I shoot rodeo's for a living, and out of about 500+ shots, I may have 3 that are OOF due to tracking issues per shoot. So..... It CAN be done. Practice, practice, practice...

cecilc · June 28, 2007

Papy wrote:

I have a 30D in the mail right now and was wondering is it posible to set up back button fucusing?

Thanks,
Ryan

Absolutely .... check your manual. The options for that are in one of the menus ....

sirsloop · June 28, 2007

Dbl wrote:

I am curious why you shoot flag football in Tv mode?

likely to ensure a fast shutter speed regardless of lighting conditions. A lot of times on partially overcast days one moment you'll be shooting f/5.6 1/1250, and the next moment a cloud rolls over and bam you're shooting f/5.6 1/320. By setting the camera up in Tv you'll ensure that you get, say 1/1000, and anything under that will be underexposed a stop or so. As long as you are shooting relatively low ISO you can easily put a stop back in if shooting raw.

2whlrcr wrote:

Another problem I have is I don't necessarily want my main subject centered in the shot. I know this really throws the AI out of whack. I hate to shoot wide and then crop later, because I like to keep as shallow depth of field as possible.

If you are tracking with AI Servo, if you bump off the subject for just a moment the camera usually doesn't switch on you. I'm talkin like a fraction of a second. On some tracking shots I do, the horses body and rider's body lines up so the center dot is kinda next to the riders belly but pointing at the background. If i'm quick on the shot the camera doesnt have time to react. Also, get good at changing between AI Servo and One Shot. I can do it in an instant without looking. Its not good for tracking, but works great for quick portraits on the fly. I switch constantly when shooting dressage... just remember to switch back

SDJames wrote:

It's low impact, beginner's football...

...you try to grab the velcro flags instead of tackling.

Take a knee!! Get down on their level so the background you are shooting at is further away!

Dbl · June 28, 2007

sirsloop wrote:

likely to ensure a fast shutter speed regardless of lighting conditions. A lot of times on partially overcast days one moment you'll be shooting f/5.6 1/1250, and the next moment a cloud rolls over and bam you're shooting f/5.6 1/320. By setting the camera up in Tv you'll ensure that you get, say 1/1000, and anything under that will be underexposed a stop or so. As long as you are shooting relatively low ISO you can easily put a stop back in if shooting raw.

If you are tracking with AI Servo, if you bump off the subject for just a moment the camera usually doesn't switch on you. I'm talkin like a fraction of a second. On some tracking shots I do, the horses body and rider's body lines up so the center dot is kinda next to the riders belly but pointing at the background. If i'm quick on the shot the camera doesnt have time to react. Also, get good at changing between AI Servo and One Shot. I can do it in an instant without looking. Its not good for tracking, but works great for quick portraits on the fly. I switch constantly when shooting dressage... just remember to switch back

Take a knee!! Get down on their level so the background you are shooting at is further away!

The situation you are describing above makes shooting in Av all that more important. That is what Av does, adjusts shutter speed to maintain the PROPER exposure, I would not advise underexposing your shots with digital. A better way is to shoot Av and if your shutter speed drops to low, bump up your ISO, this way you keep PROPER exposure and shutter speed up.

If you move your focus to your back button there is no reason to switch between AI servo and one shot. If you want to grab a static portrait simply remove your finger of the back * button and take the shot. Push the button again to start tracking. Much simpler than changing between focus modes. There is no remembering to switch back and forth.

Everyone has there own style of shooting, find what works for you and be happy. I really can't imagine that intentionally underexposing to correct in post is a good way to get the optimum out of your images.

mercphoto · June 28, 2007

Dbl wrote:

The situation you are describing above makes shooting in Av all that more important. That is what Av does, adjusts shutter speed to maintain the PROPER exposure, I would not advise underexposing your shots with digital. A better way is to shoot Av and if your shutter speed drops to low, bump up your ISO, this way you keep PROPER exposure and shutter speed up.

I agree 100%. If high shutter speed is your priority, and with stick-and-ball sports it is, shoot AV mode and open the lens up to f/2.8 and keep it there. Bumping ISO is better than pushing an under-exposed image.

mercphoto · June 28, 2007

2whlrcr wrote:

I've got a 30D and use my 70-200 2.8 IS and 17-55 2.8 IS as my primary lenses. I shoot a lot of motorcyle action that is coming towards me.... I'm always shooting at F2.8-4.0 to keep a SDoF.

You might be surprised just how shallow your DOF is at f/2.8 and 200mm. Its likely you cannot get the entire motorcycle in-focus to begin with. You might also be surprised how shallow a DOF you can get with a 200mm lens even at f/5.6.

Close down your aperture a bit more. Shoot at 200mm, to make the DOF shallower. And choose angles that have the background as far away as possible from the rider, so that they are more out of focus.

Or get a 1-series.

sirsloop · June 28, 2007

I shoot Av and simply watch shutter speeds, but I was just describing a reason you might want to shoot Tv. I know at least one pro that shoots NFL shoots Tv. When it comes down to sports, shutter is king. If you are working in mixed lighting you absolutely want to have your shutter above X speed. (~1/500th). A motion blurred photos is generally useless, unless you were panning or something. Some ISO noise or grain from jacking raw exposure up isnt really gonna effect a 150x250px image on jets.com

2whlrcr · June 28, 2007

mercphoto wrote:

You might be surprised just how shallow your DOF is at f/2.8 and 200mm. Its likely you cannot get the entire motorcycle in-focus to begin with. You might also be surprised how shallow a DOF you can get with a 200mm lens even at f/5.6.

Close down your aperture a bit more. Shoot at 200mm, to make the DOF shallower. And choose angles that have the background as far away as possible from the rider, so that they are more out of focus.

Or get a 1-series.

All good info. I've shot at f/4.0 at full 200mm and it works well, but most times shooting just over 100mm and need full aperture. Maybe I shoud just back up more, but some of these tracks are tight and I get too close to an ajoining straight.

2whlrcr · June 28, 2007

sirsloop wrote:

Also, get good at changing between AI Servo and One Shot. I can do it in an instant without looking. Its not good for tracking, but works great for quick portraits on the fly. I switch constantly when shooting dressage... just remember to switch back

Why wouldn't you use AI Focus in this situation? Doesn't it switch automatically between static and moving shots?

sirsloop · June 28, 2007

2whlrcr wrote:

Why wouldn't you use AI Focus in this situation? Doesn't it switch automatically between static and moving shots?

Are you going to depend on the camera to decide to focus on the horse???

No way its gonna get it right...

Ive taken some stupid amount like 80,000 photos in the last year... and I don't think I've ever had my camera set on AI Focus. Its like setting it on the green box...who knows what you're gonna get...

jbr13 · June 28, 2007

I agree with what several have said already, shift the focus to the AE/AF Lock button on the back. For sports, I love it! I don't know if you can beat it for moving action! You can pan with the movement and still shot away.

Jason

crgphotographer · June 30, 2007

I am feeling a bit "green"

about having to ask what is back button focussing? Can someone run through what it takes if you want a photo of a car that is going pass you?

Whenever I am taking shots of a moving subject I always track the subject with AI Servo on and the shutter button half-pressed for focus, then when I have the frame I want I press the button further. It seems to work for me, so is it that I have a steady finger or will this other system work even better? How will the back button change that?

/craig.

Dbl · June 30, 2007

crgphotographer wrote:

I am feeling a bit "green" about having to ask what is back button focussing? Can someone run through what it takes if you want a photo of a car that is going pass you?

Whenever I am taking shots of a moving subject I always track the subject with AI Servo on and the shutter button half-pressed for focus, then when I have the frame I want I press the button further. It seems to work for me, so is it that I have a steady finger or will this other system work even better? How will the back button change that?

/craig.

Craig,

I'm not sure what equipment you have but I will explain the Canon setup to do this. You are moving the focus from the shutter button to the * button on the back of the camera. This allows you while in AI Servo to continuously focus as long as the * button is depressed. When you are ready to take the picture just press your shutter button. This also allows you to focus on a subject, let up on the * button, re-frame your shot and now take the picture without your focus changing.

On the 20D, 30D, MarkIIN you make this change through the custom functions. CF4 option 3 is what I use. It works well for many, but it may or may not fit your style of shooting. It does work well for the situation you are describing with cars.

crgphotographer · June 30, 2007

Dbl wrote:

Craig,

I'm not sure what equipment you have but I will explain the Canon setup to do this. You are moving the focus from the shutter button to the * button on the back of the camera. This allows you while in AI Servo to continuously focus as long as the * button is depressed. When you are ready to take the picture just press your shutter button. This also allows you to focus on a subject, let up on the * button, re-frame your shot and now take the picture without your focus changing.

On the 20D, 30D, MarkIIN you make this change through the custom functions. CF4 option 3 is what I use. It works well for many, but it may or may not fit your style of shooting. It does work well for the situation you are describing with cars.

Ahhh... DING! Thanks, got it now... I will definately have to try it out and see it's effects (by the sound of things, pretty good once you get used to it).

Thanks Dan!

2whlrcr · June 30, 2007

Dbl wrote:

Craig,

I'm not sure what equipment you have but I will explain the Canon setup to do this. You are moving the focus from the shutter button to the * button on the back of the camera. This allows you while in AI Servo to continuously focus as long as the * button is depressed. When you are ready to take the picture just press your shutter button.

Well, I'm going to ask a really dumb question. I too have a 30D. Doesn't depressing the normal shutter button halfway, track the focus in AI Servo?

And which back button are you using? The one that changes focus points? The "set" button? Or the two little ones in the upper right hand of the body?

Dbl · July 1, 2007

2whlrcr wrote:

Well, I'm going to ask a really dumb question. I too have a 30D. Doesn't depressing the normal shutter button halfway, track the focus in AI Servo?

And which back button are you using? The one that changes focus points? The "set" button? Or the two little ones in the upper right hand of the body?

Yes, depressing the shutter button halfway does track focus in AI Servo. By changing Custom Function 4 option 3 you will move the focus to the back * button. On the back of your camera at the upper right side you will see the * symbol above the button. Of the two buttons there it is the one nearest the view finder. The one on the right changes your focus points. Hope that helps.

jbr13 · July 1, 2007

I don't know if all Nikon's are like the D50, but mine is on the AE/L button on the back. With my Nikon I can hold my shutter button down and then when some thing fast comes at me I hit the back button and once it focuses the camera fires. IT will only fire the shutter once it is in focus. I think the biggest thing is that you become more aware of your focus point. You start making sure your center point or focus point you are using is really on the subject. I don't get nearly as many pictures of stuff where the focus was on something in the background, or to the side a little.

Jason

Dbl wrote:

Yes, depressing the shutter button halfway does track focus in AI Servo. By changing Custom Function 4 option 3 you will move the focus to the back * button. On the back of your camera at the upper right side you will see the * symbol above the button. Of the two buttons there it is the one nearest the view finder. The one on the right changes your focus points. Hope that helps.

mercphoto · July 2, 2007

Dbl wrote:

Yes, depressing the shutter button halfway does track focus in AI Servo. By changing Custom Function 4 option 3 you will move the focus to the back * button. On the back of your camera at the upper right side you will see the * symbol above the button. Of the two buttons there it is the one nearest the view finder. The one on the right changes your focus points. Hope that helps.

I think what he is getting at is why is AF tracking more desireable with the * button than with the shutter button half-depressed? I, too, understand what the custom function does, I just don't know why its beneficial.

Dbl · July 2, 2007

mercphoto wrote:

I think what he is getting at is why is AF tracking more desireable with the * button than with the shutter button half-depressed? I, too, understand what the custom function does, I just don't know why its beneficial.

Well the method certainly doesn't work for everyone.

I like it because I find it easier to not have my finger pushed 1/2 way on the shutter, I tend to fire off shots when I don't want to. This way I only push the shutter when I want to shoot.

I like it because it is like having AI Servo and One shot all in one. Servo as long as the button is pushed, let up on the button and you have one shot.

I like it because it allows me to focus, lock on the subject, reframe a shot and then push the shutter to take the shot (Think baseball batter, or play at a base).

I like it because it retains manual focus capability on an autofocus body. You can quickly tweak a focus if you want manually with no switching or moving additional buttons.

I like it because I can actually focus, let up, move to a more desireable spot for metering and hold the shutter half way, reframe and shoot. Use CF4 - 1 for this trick.

Again it is not for everyone, many sports shooters prefer it, but I know a few who don't.