Which f-fstop for shooting bikes & other questions

[Shabok]

Hi all,

I've been shooting mountain biking (mainly dh races) for a couple of years with Canon DSLR's (first the D30 followed last year by the 10D). I've always been a bit frustrated by their AF performance when shooting riders coming head-on. Given the EOS 1 series' AF reputation, I got the 1D Mark II one month ago. Surprisingly I haven't noticed any real improvement in AF performance when shooting in AI Servo (with the 70-200/2.8L). I think there are several factors that come into play :

1. I'm maybe using AF settings that don't work too well in this situation. So I would be very grateful if 1D (Mark I or II) owners could tell me which settings they use, in particular the number of AF points (all 45, only one, center or not), CF17 (AF point activation area, I've tried CF17-0 and CF17-1), CF20 (AI Servo tracking sensitivity, it shouldn't affect tracking speed but you never know ;))
2. The 1D Mark II, with both a bigger sensor (=> less DOF) and more resolution tends to show slight misfocusings more than a 10D
3. Shooting at 200mm and f/2.8 (when filling the frame with the rider) should maybe be avoided ? I like having a very shallow DOF for good subject separation and thought that shooting wide open with the 70-200mm and focusing on the number plate would result in nice loooking shots. However, my results show that often I only get the back wheel focused, or the front wheel, but the focus rarely *nails* the subject. I also get frequent misfocusing when the rider doesn't fill the frame in spite of the fact that I have more DOF. What f-stop are you shooting bikes with ?

Any input would be greatly appreciated !

Here are a few shots that I can't get systematically sharp (~50% of OOF shots), even when shooting in bursts :














By the way, here are the full galleries' url's (shot with the 1D Mark II) :

http://www.nobrakes.ch/lyon2004.php
http://www.nobrakes.ch/ixsdhcup1_04.php

Thanks

[Photo-John]

Good to see you on our new sports photo forum. This type of question is one of the reasons I started this forum. AF techniques are tricky, and vary from camera to camera. I'm the opposite of you. I got the 1D first, and then got a 10D as a backup and riding camera. I was used to the super-accurate AF of the 1D and have had a lot of trouble with the 10D.

The 10D has a much bigger sensor and that's probably part of the reason you're having trouble. I had an EOS 3 before my 1D so it wasn't such a big difference. I only use the center focusing point as it's the most accurate and reliable. For shots like you've posted, where a dh rider is coming at me at high speed, I do my absolute best to keep the focus point on the rider's head or number plate. One problem I have is focusing on the rider's middle and losing the number plate and head sharpness. I usually shoot a little wide to give myself room to crop, later, since I end up shooting crummy compositions in order to ensure good focus. I also don't use all 45 focus points. There's a custom function that limits the number of focus points. That improves AF speed and accuracy.

The problem I've had with my 10D is that it doesn't focus where I expect it to. I'm used to being able to focus on very small spots with the 1D. The 10D often doesn't focus where I expect it to. I've found that I just can't be as accurate with it as I can with the 1D. This is especially true with mountain bike landscapes where I prefocus on a spot and the rider is a tiny portion of the image.

I want to get a Mark II but can't afford it right now. I'd love more resolution and I know I'd have a better success rate with better AF. Although the 1D is already so good I couldn't believe it when they said the Mark II was better.

Make sure to post a review for your Mark II! It's tough to get reviews for the real pro gear. And we need them.

Oh yeah, those photos are awesome. Most people would be overjoyed to get one photo like those. But I know how it is. The success rate is never good enough.

[Shabok]

The 10D has a much bigger sensor and that's probably part of the reason you're having trouble. I had an EOS 3 before my 1D so it wasn't such a big difference. I only use the center focusing point as it's the most accurate and reliable. For shots like you've posted, where a dh rider is coming at me at high speed, I do my absolute best to keep the focus point on the rider's head or number plate. One problem I have is focusing on the rider's middle and losing the number plate and head sharpness. I usually shoot a little wide to give myself room to crop, later, since I end up shooting crummy compositions in order to ensure good focus. I also don't use all 45 focus points. There's a custom function that limits the number of focus points. That improves AF speed and accuracy.

Yes I also often get the rider's torso in focus whereas the number plate and face are OOF. The focus point is so small that it's easy to miss the target. But as you do I prefer small AF points than big ones like on the 10D that you never know what they will focus on...

Do you use the AF point expansion custom function with the center AF point ? And do you think that shooting those riders coming at you at full speed require f-stops smaller than f/2.8 ?

Make sure to post a review for your Mark II! It's tough to get reviews for the real pro gear. And we need them.

Yep I'll post a review when I'm more accustomed to the camera, it offers so many options that it's a bit confusing at first

Oh yeah, those photos are awesome. Most people would be overjoyed to get one photo like those. But I know how it is. The success rate is never good enough.

Thanks John for the comment ! Yeah, the success rate is never good enough as by Murphy's law I'll always screw-up the shots that are most important, and at the last race I've already lost a couple of sales because of bad focus. But I think this how it is in sports photography, as I read it in the following article :http://www.robgalbraith.com/bins/mul...id=7-6453-6821 ;)

[ironlegsracer]

Yep,to an untrained eye those are perfect.I see a couple of small problems,but would still be thrilled with shots like that.They are good and only because they're yours do you notice all the imperfections.I can never look at enough cool bike shots.Keep sending them!

[another view]

Great post. I've been working on this more lately with my Fuji S2 (not a sports camera!) which is built on a Nikon N80. I have a problem with moving subjects - I also don't get the focus area I think I'm getting and my success rate is pretty low too. I'm only using the center focus area (cross sensor) which is most reliable, but not perfect. Didn't have much problem with my Nikon F100, and now that I've learned more about it I'm going to try that one again with sports of some sort.

I'm not looking for an excuse to buy a D2H (or D2X when it comes out) but it's got me thinking...

John, what do you do to try to improve your odds with the 10D? Any suggestions? I know Sebastian says he has better luck with his 10D than he did with the Nikon D100 (also Nikon N80 body) so I can use any tricks I can get!

[Sebastian]

Great post. I've been working on this more lately with my Fuji S2 (not a sports camera!) which is built on a Nikon N80. I have a problem with moving subjects - I also don't get the focus area I think I'm getting and my success rate is pretty low too. I'm only using the center focus area (cross sensor) which is most reliable, but not perfect. Didn't have much problem with my Nikon F100, and now that I've learned more about it I'm going to try that one again with sports of some sort.

I'm not looking for an excuse to buy a D2H (or D2X when it comes out) but it's got me thinking...

John, what do you do to try to improve your odds with the 10D? Any suggestions? I know Sebastian says he has better luck with his 10D than he did with the Nikon D100 (also Nikon N80 body) so I can use any tricks I can get!

Not John, but I'll try. The D100 was coupled with rather slow lenses. I think the main reason I am getting better luck now is because of the much faster USM on my 70-200. The center focus point is always the way to go. Problem with the 10D is the sensors are MUCH larger than the indicators, and when the subject is small in the frame the area of focus becomes sort of a crap shoot.

The Nikons based on the N80 have nice tight focus sensors, I think your rpoblem is that the two-ring 80-200, as fast as it is, still can't keep up. Try the F100, it did much better for me than the D100/N80.

[Photo-John]

John, what do you do to try to improve your odds with the 10D? Any suggestions? I know Sebastian says he has better luck with his 10D than he did with the Nikon D100 (also Nikon N80 body) so I can use any tricks I can get!

Are you prefocusing? I have accpeted the fact that I can almost only prefocus for sports photos with the 10D. The AF is actually pretty fast. It's the accuracy that's a problem. I can't focus on anything very small, and if I'm at all unsure, I stop down to pad my depth-of-field. I also zoom in and focus closer, when possible. Like Sebastian said, precise focusing with the 10D and a small area is pretty much a crapshoot. And the odds aren't so good.

When in doubt, prefocus and time your shot carefully. That's the sure thing.

[another view]

Are you prefocusing? I have accpeted the fact that I can almost only prefocus for sports photos with the 10D. The AF is actually pretty fast. It's the accuracy that's a problem. I can't focus on anything very small, and if I'm at all unsure, I stop down to pad my depth-of-field. I also zoom in and focus closer, when possible. Like Sebastian said, precise focusing with the 10D and a small area is pretty much a crapshoot. And the odds aren't so good.

When in doubt, prefocus and time your shot carefully. That's the sure thing.

Thanks - no, I'm not prefocusing. I'll have to try that because what you both describe is exactly what's happening. Closing down a stop or two usually helps, but I like wide apertures in a lot of cases and sometimes need them for good shutter speeds.

[Shabok]

Are you prefocusing? I have accpeted the fact that I can almost only prefocus for sports photos with the 10D. The AF is actually pretty fast. It's the accuracy that's a problem.

Yes the 10D's AF is actually pretty fast and I get almost as many keepers with it as with the 1D MarkII. Here are a few pictures shot last year with the 10D using the AI Servo focusing mode, all were shot wide open (f/2.8) unless noted :














(shot at f/4)



Hope I'm not posting too many pics, in which case I'll replace them by links

[Photo-John]

That's good to know. I have had a hard time trusting AI Servo with the 10D. Your photos giv me faith. Of course, you do have to fill the frame as much as possible to ensure focus, though. I love the tiny focus points on my 1D!