I attemp to do quite a few 'walking toward and away' shots with my wedding parties. I find it's a great way to get relaxed, natural expressions....and I just love the look of the movement.

I'm having heaps of trouble getting good focus with these. I've tried AI Servo and AI Focus, and the camera just doesn't seem to 'lock on' to the subjects movement. It sounds rather dumb, but I'm not sure what to do with the shutter either. Because I'm not getting sharp focus, I tend to keep re-pressing the shutter....looking for focus! I take SO many, I end up getting a few good sharp ones (though they never seem to be the best expressions!!! grrrrr!)

After reading this post I decided maybe the answer to this problem was to use ALL the focus points. (I actually asked this same question in that thread...but it got buried)

So....I just spent half an hour shooting my 5 year old running up the garden path toward me. I tried all the focus points, centre point only, AI Servo, AI Focus.....I even resorted to 'Sports Mode' ha ha ha. I had VERY fast shutter speeds. I tried everything. BUT...the results are crappy. I've just had my 30D's focus and metering re-calibrated by Canon, so it's most likely not the camera. It must be my technique!

Any advice would be deeply appreciated. I'm sick of swearing at my potentially gorgeous wedding shots that are NOT SHARP. If I could get a handle on how best to do this, I'd be a very happy girl!!!!


Annie

You want to use AI-Servo - but if you read up on it, you'll see that it can take up to a second or more for it to lock on to your subject. (And don't forget that it's designed for subjects moving at a predictable rate - not erratically - and you need good light and a high-contrast subject to lock on to.)

So you need to either keep the shutter down and shoot a full auto sequence or move the AF function to the AE button (using your custom function) so that you can start and stop AF independently of the shutter.

I'd just use a single focus point on your desired point of focus and crop later unless you have a lot of depth of field to work with.

It's funny, because Denis Reggie swears by the AI servo. But I have lots of trouble with it too..especially when I need it most (processional, recessional). He basically, nicely, told me that I need to learn how to use my camera properly. But I swear, it doesn't work for me the way he describes. He must have a technique--like stated above--where you lock on a subject moving at the same rate etc.

I hear you though, and feel your pain. It's not just you. Too bad, huh? Cuz, on paper it's a cool feature.

G

Thanks for that Geneve...yeah focus seems to be the bane of my life! I can fix all manner of exposure errors in PS....but a poorly focused image is trash, no matter how fantastic it WOULD have been! I will persist. I'll try what John suggested with moving focus to the 'other' button via custom settings. I have already had a play around with that, just not in this application. I hope my little boy is feeling fit....cause I intend on asking him to run up and down that garden path a whole lot more this week. I have a wedding on Saturday, and I want results!!!! ha ha ha ha ha

and John, thanks so much for your reply. As I just said, I will indeed try what you suggested with the custom functions. I'll also try to wait for that 'lock on' you talked about.

One question...what is AI Focus meant for? Just curious.....

In regard to the focus point selection....if I had a 'couple' or a row of people, would it be better to use multi-point focus? I guess I'm wondering about that single focus point landing in between my subjects in my composition, and therefore not locking on......

Also, I have to ask you this, as I'm well aware you have strong opinions on the focus capabilties of the 'lower end' Canon SLR's. I'm seriously thinking about updating to a pro level camera later in the year. Do they really focus more accurately and consistently? I feel like I've been constantly let down with focus on my old Rebel and my new 30D. I've updated to all L series and prime lenses....and I still constantly get lots of soft images. I'm aware of my shutter speed and apeture playing a part in this sometimes....but not always. I want sharp images....end of story. (doesn't everyone)
Which pro level camera should I consider? Would it be noticably better than the 30D's focus...or am I too quick to blame my gear? I wonder........

Annie

The only digital cameras out there right now with pro-level autofocus are the 1D series and the D2 series.

And there is a noticeable difference. I still have my eos3. I was asked to shoot b/w at a wedding last year and I was amazed at just how much better the autofocus was - how much quicker it locked on accurately on even in poor light. You still have to use good technique, but you aren't fighting the camera every step of the way.

And with 45 focus points and 11 spot meters, you can capture action a lot better than with something like a 30D.

There's no reason Canon couldn't put that metering and autofocus into a camera that costs less than $2K (a lot less).

About AI Focus:

"AI focus mode focuses on the subject using One-Shot mode, but if the camera detects that the subject then starts to move, it automatically switches to AI servo mode so it can keep the subject in focus. AI focus mode is the autofocus mode selected for you in Full Auto and Flash Off modes. It can be selected in any Creative Zone mode."

The problem again is that servo needs a subject moving at a constant rate (or a constant rate of acceleration) relative to the camera and it needs time to determine that.

So... am I better off to manually switch between 'one shot' and 'AI Servo'.....rather than using AI Focus?

Still curious on whether multi point focus would be better for 2 or more people...
I think sometimes a single point could end up over the background...

Then with one person I would use single point?

Annie

Here are my findings and experiences with AI-Servo.

1. It's better to choose Single Shot or AI-Servo instead of AI-Focus as it takes some time for the camera to determine that the subject has moved and in that time you'll have an OOF period.

2. The 30D has a relatively large gap between the center point and the outlying diamond points. This gap means that the camera will probably lose tracking if the subject is small enough that it can't cover both the center and the outlying point to which it will be handed off. The 5D mitigated this by adding six invisible points around the center to aid in AI-Servo tracking. The 1D bodies, of course, are servo tracking maniacs but you pay for all those extra sensors.

3. The focusing area which the camera sees is larger than the small boxes in the viewfinder. If the focus point drifts towards the edge of the target, it may lock onto a contrasty background around the target and miss focus. The focus screen can also shift slightly meaning that the center of the focusing area may be slightly offset from the focus point.

4. The center focus point has two advantages. First, it's a high precision sensor meaning it can focus to within 1/3 of the Depth of Focus with f/2.8 or faster glass. All the other 30D points are normal precision even with fast glass which means anywhere within the Depth of Focus. The second advantage is that it is a cross sensor, meaning that it can sense edges both vertically and horizontally which means a better chance of mainitaining focus on any normal subject. I prefer the center even if I have to frame loosely and crop in post for best composition. I have gotton good AI-Servo captures with the outlying points, but the keeper rate is lower.

5. C.Fn 4-1 or 4-3, moving the focus to the * button, is the technique I've settled on. I used to go back and forth between that and the standard focus depending on whether I was shooting "sports" or portraits, but I often got confused so I settled on back button focusing. The back button allows me to focus and recompose in AI-Servo by just lifting my thumb off the button to stop the tracking before I shift comp. Normal shutter button focusing doesn't allow that option. The difference between 4-1 and 4.3 is that one will allow you to lock exposure on the half press while the other waits until shutter release to determine exposure. I shoot manual 90% of the time so it doesn't make any difference to me.

6. All the camera up until the 1D Mk III have had the first shot in continuous AI-Servo be "Shutter priority", which means the shot is taken even if the focus algorithm isn't sure of the focus. You'll get the shot, it just may be OOF. All the subsequent continuous shots will be "Focus Priority", meaning the camera may delay taking the shot if it's still determining a predictive focus solution. I've found that if I take short bursts of 2-4 shots, the second is almost always in better focus than the first.

7. In my experience, the lens makes a huge difference. My 85 f/1.8 USM is my best tracking lens. On the other hand, my retired 50 1.8 (plastic) was atrocious in AI-Servo.

8. The most important element in AI-Servo tracking is selecting a good contrasty focus target and KEEPING the focus point on that target throughout the shooting. This takes mucho practice. My 6 yr old just started t-ball and the 800+ of practice shots I've taken have improved my confidence and keeper rate significantly. With practice, you'll also be able to tell in the viewfinder if the camera is having an easy or hard time determining focus by the amount of hunting involved.

Canon has an excellent PDF on focusing available here:

http://www.usa.canon.com/content/Handling/EOS_Digital.pdf

GETTING THE MOST FROM YOUR EOS-1 CLASS DIGITAL SLRTIPS AND TECHNIQUES: CAMERA HANDLING & MAXIMUM IMAGE QUALITY

Sorry for the length, Annie. Good luck and God Bless.

s

Personally I ALWAYS shoot in AI servo. I use custom setting #4 (set to option 1) and use the * on the back of the camera by your right hand thumb to focus. It takes a bit of getting used to, but once you try it most people never go back. Pepper Nix was the one who got me to try it, and after playing around with it, I'd never go back. I know Becker (and I think Dennis Reggie) use this method exclusively too.

The whole point behind it is the seperating the shutter mechanism from the focusing. They are two totally different things and should be operated differently. When you want the camera to focus press the * button (again you always keep your camera in AI Servo for this.) When you want it to stop focusing take your thumb off the * button.

Also, I don't care what people say about the focus systems of the 20D/30D or 5D, I think for wedding/portrait work there is absolutely no reason why the AF system in those cameras isn't perfectly capable of handling whatever you give it. I almost never have soft/out of focus images that are a result of the AF system in those cameras.

YAY! Thank you guys for expanding this! I knew there was something I wasn't doing right--Denis Reggie was right...I don't know a darn thing about my camera.

Steve--PS--I use the 1Ds MkII and I STILL have trouble!

That would work great - if you have a 1D or similar with a lot of good autofocus points. Not very helpful on a 20 or 30D where only the center point is worth using (unless you're in bright sun).



Wedding and portrait work are two different things. With portraits you can control your light and chimp to your heart's content - with wedding work, you can't.

Wedding work is the most demanding type of action photography there is - much more demanding than either sports or news photojournalism. We are not only working with more types of lighting situations (often changing from shot-to-shot), but we are actively seeking out the most difficult types of lighting in order to get artistic shots - not merely record the action.

With only one spot meter and only one adequate (not great) focus sensor, the 30D and 5D are extremely poor at capturing wedding action - so you either change your shooting style and look for static shots in good light - or you shoot more and chimp a lot to make up for the camera's deficiencies.

Dang... Now I gotta go change my shooting style. Thanks a LOT!


j/k

My favorite quote was in a Rob Galbraith article on the Sports Illustrated superbowl images workflow. Here's SI's director of photography reviewing images during the game...



Most of these guys were using 1D bodies. Makes me feel better when I find occasional soft or OOF images.

Chris - Thanks for that tip, I immediately grabbed my 30D and tried a few shots using the Custom Funciton #4!

No problem. It'll change your life!

*walking to my car to get my camera and try this out*

Back soon.

Sorry? Nevermind saying sorry!

THANK YOU Steve.....
thank you SO much! That's one hell of a response....and thanks for the links as well. I intend to try everything you suggested....even the part about the 85mm (I actually have that lens ) I'm also prepared to put in lots of practice...not expect miracles overnight.....and even plan on buying a 1D MkIII later in the year!

Chris...thank you also for your input!
This may be a dumb question, but does the technique you described refer to using multi frames only (motor drive) OR single frames as well. I haven't been using motor drive for these 'walking' shots, mostly because I shoot RAW and it rips through so many very similar images...so quickly. I'm certainly prepared to give it a try though.
I would prefer to have the focus 'track' and then just choose my single clicks....I think... ha ha ha




Wow John...I really appreciate this quote. I was talking to a photog friend about exactly this the other day. I was complaining about my own insistance of looking for the most difficult lighting situation possible....because I thought it looked more artistic and beautiful. There is so often a much easier, straightforward way....with easy natural light. But oh no....I always seem to want the artsy shot, which pushes my flash and metering knowledge to the limit (and often BEYOND...ha ha ha) AND all this under unbelievable pressure and time constraints. I have no intention of quitting, or changing this strategy, but sometimes I wonder why I make things so difficult for myself!
Nah....I know. I want to push myself, better myself and impress the socks off my client.



I clearly fall into the second of these 2 options

(I feel shame about this though)


Annie

I'm a servo shooter - almost exclusively.

You kinda have to cross reference both what is important (your subject) and what the camera can realistically focus on. So you have to choose something with contrast so the sensor has something to pickup. I didn't see what camera you're using - but I use the Canon 1 series becuase of the extra focusing points and the brighter viewfinder. I feel it makes a big differece to be able to rotate points to place the subject in the frame - while tracking them in front to back space.

So from your example with a 'party' walking toward you. Focusing on their face or their hips will give you a subject that doesn't track too fast (as compared to swinging arms). Also use a reasonable F stop.

Anyone have a 5D to sell to me now?

Can anyone transpose this thread to Nikon verbage? What is a Servo?

I'm almost always using the motor drive. It shouldn't make much difference though either way you do it.

Also, as I've noted I really don't buy into the notion that John is describing that the 5D/20D have terrible AF systems. Personally, I don't have any problems with it at all, my 5D and 20D are tack sharp and locks focus on moving subjects even in very low light very very well and I see tons of people every day posting up amazing images with those cameras and they don't seem to have any problems either so I'm not quite sure what's up.

If I am not mistaken, AI-Servo is the equivalent of AF-C (Auto focus continuous) for Nikon.

Then you have the only ones - or your definition of low light is a lot different. (I've used my 20D for marching band competitions in bright sun and it works great - in servo and with all the focus points. I guess I'll just have to start refusing weddings that aren't in the middle of a football field at noon.) As for images posted online, the lower resolution and some judicious unsharp masking can hide a multitude of sins. And even then I still see a lot of soft images on people's websites.

I'm selfishly bumping this so hopefully when I wake up in the morning I can re read this with a fresh brain and do some work.

I've been digging around tonight researching and had to resurrect it.

Good on you Betsy! I'm re-reading the whole thread too. (and I was the OP...!!!)

Great info from some of our knowledgable OSP members.

i definitely recommend listening to any advice chris humphreys gives. he is the only other photog i list on my blogroll, and that is for a reason!

This is super fascinating.. It's something I wanted to know more about as well. I love the people on OSP.. They know what they're doing! And they're willing to teach the rest of us.

I shoot a D3, and I'm always in AF-C (continuous, or servo) mode and I use the back button to focus. There ain't no better way to go if your subject is moving. I also keep a focus point on whatever I want to focus on. So basically, if I had a wedding party walking towards me, I'd stick my focus point on the groom's face, hold in the AF-ON button, and shoot away.

Servo / * button / Av / Tv / AI Servo / etc....why can't Canon name things in normal language instead of engineer-speak?