Am I asking too much of a 50d plus 70-200 f/2.8

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Archive 2009 · Am I asking too much of a 50d plus 70-200 f/2.8

volyrat
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p.2 #1 · Am I asking too much of a 50d plus 70-200 f/2.8

The DOF calculator does take into account that it is a 1.6 crop camera. Still says I've got 2 feet of DOF @ f/2.8.

walter23 wrote:
volyrat wrote:

The DOF calculator that I use says at 50 ft, 200mm, 1.6 crop and f/2.8, I should have about 2 feet of DOF- 1' in front and 1' behind.

With 2 feet of DOF, do you think that's the problem?

DOF calculations assume a standard print size. If you look at the standard web-sized version (your first image), she is sharp - within the DOF, albeit at the front edge of it (so not as razor sharp as she would look if she were truly in-focus). It's only when you start looking at magnified crops that you see where focus falls off. If you're going to be scrutinizing at 100%, you need to adjust your DOF calculation to account for the increased magnification.

Nov 08, 2009 at 03:57 AM

RobertLynn
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p.2 #2 · Am I asking too much of a 50d plus 70-200 f/2.8

in "theory" you have 2 feet of DoF at f/2.8. In practicality you have less. What I mean by that is, some falls in front of the point of focus, and some falls behind. Now that's saying that the things will be "reasonably" in focus, save the focus point. Obviously, the point of critical focus is going to be the sharpest.

I don't have a 50D, but I do have a 40D. I would think that in websize images, the combo would be sharper, because of the added benefit of down-rezzing the photo.

The first thing I would do is test the camera in a controlled environment. Tripod, timer release, high contrast area to lock focus and I'd do repeated focus on the subject and focus on something else then bring back focus to the subject.

Take several exposures, and do the typical processing youw ould do. Now I understand that processing different types of photos requires different types of sharpening.

I take a lot of portrait photos with my 70-200, and have done some sports with it. It focuses quickly. I get misses and I get hits.

Your shutter speed looks quick enough to freeze motion, and the grass looks sharp. So now the question is, is the AF just not keeping up, and this is just a case of the Servo being a little bit of a punk.

Nov 08, 2009 at 04:20 AM

Dawei Ye
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p.2 #3 · Am I asking too much of a 50d plus 70-200 f/2.8

I agree with Robert that this is possibly an AI Servo focus issue

RichardLavigne wrote:
As others have said... you have plenty of room in terms of shutter speed, so you could shoot that at ISO 400, 1/800 and f/5.6 have still stop all of that motion with a sharper image... why does it HAVE to be shot at f/2.8?
I really disagree here

Firstly, lack of DOF?

Surely DOF cannot be the scapegoat in this case for the softness. I'm just starting sports photography myself and I use a 200L at f/2, and this is more than enough DOF to get everything I need in focus... Somehow I don't think f/2.8 is "thin" or the culprit for these issues. Even my 85 @ f/1.2 has enough DOF to get a person in focus for sports

And stop down? Most sports photographers use these lenses wide open...the times I used this lens I never went below f/3.2

f/2.8 also gives you better subject isolation - and part of the reason why this lens is used for portraits and sports. Using f/4 or f/5.6 won't be able to replace that increased background blur.

And as the OP identified himself, what about when he needs the speed of f/2.8? And what would have been the point of getting this lens over the f/4 version if it is to be used at f/4 or f/5.6?

It's totally unreasonable to expect the OP to have to stop down this $1600 L lens which performs excellently wide open for many, many, many photographers.

Nov 08, 2009 at 04:38 AM

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p.2 #4 · Am I asking too much of a 50d plus 70-200 f/2.8

I guess the old adage, "F8 and be there" ain't so righteous anymore.

My thought is the OP wants a solution for tomorrow's shoot, so stopping down is one way of increasing the odds of a sharp capture. When he has the time, he can either buy a new camera or get his calibrated. Meanwhile, shooting at F2.8 is producing soft images and will continue to do so no matter how many times he dials in F2.8 or rationalizes the righteousness of how an L lens should perform wide open.

Nov 08, 2009 at 05:05 AM

Dawei Ye
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p.2 #5 · Am I asking too much of a 50d plus 70-200 f/2.8

+1 Yeah definitely I agree 100% with you, in the circumstances, if f/2.8 is clearly not working, unfortunately having to stop down to get the shot at the expense of other tradeoff factors would be the logical thing to do

Nov 08, 2009 at 05:14 AM

dehowie
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p.2 #6 · Am I asking too much of a 50d plus 70-200 f/2.8

Personally if using a 50D id be zooming out a little and using centre point on her face or numbers on the shirt whatever gave the best target.
A 1 series would struggle at 2.8 on an all blue uniform.
Sorry but AF is not a laser beam of death it has limitations and you must learn to work within and around those limitations.
The single biggest one is lack of tracking ability against low contrast objects and to then back it up with the narrowest depth of field from the lens and you are on hazardous ground.
I'd be saying even if your camera was working 100% properley(and it may well be) it would be struggling with this combination of factors to give you large numbers of sharp images given the criteria you are asking it to perform in.

Nov 08, 2009 at 01:06 PM

volyrat
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p.2 #7 · Am I asking too much of a 50d plus 70-200 f/2.8

I understand that DOF is in front and behind the target, with a little bit more than 50% of the DOF in front of the target.

I've tested it in a controlled environment and as I said in the original post, sent it to canon where they adjusted the focus on the lens and the body and cleaned everything. I'm assuming Canon's ability to test this is better than mine.

Thanks for the response.

RobertLynn wrote:
in "theory" you have 2 feet of DoF at f/2.8. In practicality you have less. What I mean by that is, some falls in front of the point of focus, and some falls behind. Now that's saying that the things will be "reasonably" in focus, save the focus point. Obviously, the point of critical focus is going to be the sharpest.

I don't have a 50D, but I do have a 40D. I would think that in websize images, the combo would be sharper, because of the added benefit of down-rezzing the photo.

The first thing I would do is test the camera in a controlled environment. Tripod, timer release, high contrast area to lock focus and I'd do repeated focus on the subject and focus on something else then bring back focus to the subject.

Take several exposures, and do the typical processing youw ould do. Now I understand that processing different types of photos requires different types of sharpening.

I take a lot of portrait photos with my 70-200, and have done some sports with it. It focuses quickly. I get misses and I get hits.

Your shutter speed looks quick enough to freeze motion, and the grass looks sharp. So now the question is, is the AF just not keeping up, and this is just a case of the Servo being a little bit of a punk.

Nov 08, 2009 at 01:07 PM

volyrat
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p.2 #8 · Am I asking too much of a 50d plus 70-200 f/2.8

Actually, I was asking if I was expecting too much from this body / lens combo. Should captures of moving targets be sharp, with the lens wide open, as long as I have good tracking with the focus point (and I already adjusted shooting by selecting only the center point), adequate light, and a shutter speed that's adequate to freeze the action.

I'll shoot 2 more games today, but with a 1.4 TC (70-200 is my longest lens). Because of the TC, I stop down anyway to make up for it's "weakness". I'll also use a monopod, because now I've got a 280 f/4 and it's a little overcast today - shutter speed will be hard to come by and I don't want camera shake playing a role.

Gochugogi wrote:
I guess the old adage, "F8 and be there" ain't so righteous anymore.

My thought is the OP wants a solution for tomorrow's shoot, so stopping down is one way of increasing the odds of a sharp capture. When he has the time, he can either buy a new camera or get his calibrated. Meanwhile, shooting at F2.8 is producing soft images and will continue to do so no matter how many times he dials in F2.8 or rationalizes the righteousness of how an L lens should perform wide open.

Nov 08, 2009 at 01:13 PM

WebDog
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p.2 #9 · Am I asking too much of a 50d plus 70-200 f/2.8

I still think you might have some back focus issues, try some controlled tests and adjust your camera MA (micro adjustment) to see if that helps. The drawback on having to resort to MA is it might vary over the zoom range. But it would certainly help you to track down your problems and prove that it can ge sharp pictures

Nov 08, 2009 at 01:18 PM

patriot
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p.2 #10 · Am I asking too much of a 50d plus 70-200 f/2.8

Looking at the one image you posted, would have to agree with others here that the focus does seem to be just behind your daughter's feet. Canon should have calibrated to factory specs when you sent everything back. That lens will be a little soft at either end, wide open. That said, and as someone else pointed out, you may want to consider MA wide open at 200mm if that's where you shoot a lot.

You've also got your daughter running towards you. You said you were in al servo. Target moving directly away or towards you is, I believe, most difficult for Al servo, which is better with targets moving sideways. And clothing is not always high contrast, even if there are numbers, like on her shirt. Soccer shirts are often shiny, therefor reflective, which can appear as lower contract to the AF, especially compared to sharp contrast like the grass. One suggestion to try: using Al Focus, have your daughter run towards you at the same speed. The AF may be able to do a better job with the subject running directly towards in Al Focus.

For dance, like Nutcracker, she is more likely to be moving side to side. My daughter does a lot of dance and theater. Look for the stationary moments in the scene she is in when you can. If there is lighting, you may be able to get faster shutter speeds in better lighted scenes. I mostly use Al Focus in dance.

Is that "Franklin" as in Mass?

volyrat wrote:
Dave - thanks for the response.

Agreed that I could close down the aperture in this circumstance, but what happens in 4 weeks when I'm taking shots of her in a moderately lit auditorium as she dances in the Nutcracker? I'll be at 1600 or 3200 and still only get 1/500 or so - at best.

Second, I struggle with saying grass is sharp or not sharp - I'm looking for logos, letters or something else. I've looked at the 400 or so captures from today and the focus just isn't consistent. Even 3-4 frames into a burst, when all have 9+ spotting of the focus point, I get front, back and non focus. The only thing I don't get is sharp.

And re: Micro Adjust etc - I'd be OK with this if I hadn't spent 3 weeks trying it myself, then finally sending to Canon to let them figure it out, and having them send it back in this condition. Just not acceptible.

davenfl wrote:
I share your frustration and the frustration of anyone who has focus issues with their equipment. First lets talk about your exposure setup. Per the EXIF your shooting at 200mm wide open , 2.8. That is not providing you with any margin for error at all. In these lighting conditions you could well afford to drop your ISO from 200 to 100 and shoot AV with a maximum aperture of f5.6 or less, you will still have plenty of shutter speed to stop this motion and hopefully you will end up with a bunch of shots are f4 or f8 which will give you some depth of field. I copied your full size jpeg into CS4 and took a hard look at it. A line of grass just behind her feet is clearly in focus so you need to spend some time with a static set of objects on which you can get some microadjustment done. If you shoot a lot at 200mm then MA the lens there. MA and zooms don't necessarily mix well because the focus will shift as you change the focal length but with a 70-200 and smaller f-stops you should be alright. I wish I was there to help you but it is going to be ok, really. Some exposure work, some MA, and some patience and it will work.

Dave

Nov 08, 2009 at 02:04 PM

msalvetti
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p.2 #11 · Am I asking too much of a 50d plus 70-200 f/2.8

volyrat wrote:
Actually, I was asking if I was expecting too much from this body / lens combo. Should captures of moving targets be sharp, with the lens wide open, as long as I have good tracking with the focus point (and I already adjusted shooting by selecting only the center point), adequate light, and a shutter speed that's adequate to freeze the action.

Valid advice about stopping down to help aside and getting directly at the issue, that body/lens combo should definitely be able to produce sharp images at f/2.8 in AI Servo. I mean, she's a young soccer player dribbling a ball - we're not talking Usain Bolt.

Maybe expecting all shots in a burst to be sharp is too much, but none out of 6, in bright sun, something is wrong. I agree it could be the uniform.

As a point of reference, my 40D can hit about 2 or 3 out of 6 when focusing on a streaking hockey player at ISO3200 with a 70-200 f/2.8 lens. If the 40D can do that in low light, the 50D should be able to do better much better, especially in sunshine.

Try shooting some of the opposing team (to try and eliminate uniform as the cause). If things don't improve, then it may be something about your technique.

Also, don't assume that because Canon had the camera and lens together they were able to fix it. It may need to go back again....

Mark

Nov 08, 2009 at 03:44 PM

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p.2 #12 · Am I asking too much of a 50d plus 70-200 f/2.8

I don't know much about this so ignore me if I am talking rubbish - but it seems to me to be a very low contrast area to be focussing on in the first place.

Nov 08, 2009 at 04:23 PM

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p.2 #13 · Am I asking too much of a 50d plus 70-200 f/2.8

Well, I think the problem might be shooting bursts with AI focus. I'm sure your AF could manage this just fine without that additional complication.

I think AI focus anticipates the focus by measuring subject speed and then updating focus based on that speed. Soccer players don't necessarily maintain a constant velocity; you might just be asking too much of your equipment here. Maybe she gave a burst of speed before you shot and tricked the AI? All I'm saying is that maybe you should figure out the limitations of your equipment and try to work around them.

volyrat wrote:
Agreed that a 1d series should be better, but it's not like Canon positions this as a camera without any capability for sports. I'm not trying to catch a hummingbird zipping across the yard at dusk. If the camera isn't capable, then Canon should position it as "entry level". On the contrary, Canon positions it as "the next best thing" - at least they did before the 7d.

And how would I anticipate focus when taking a burst of 5 - 10 shots using AI Servo focus? This isn't meant to be a wise guy question - if there really is something that I can do here, I'd be happy to.

walter23 wrote:
Maybe if you expect sports-capable AF performance you should shell out the money for the sports-capable AF camera, the 1D-series one. I wouldn't blame the lens. It's clearly misfocused behind her (look at the grass in the full image). If you aren't going to buy a camera with the specifications for what you're trying to do, I'd suggest you learn to anticipate focus, or otherwise modify your technique (stopping down, for example).

volyrat wrote:
So what happens in circumstances where I need f/2.8 to achieve SS?

I've heard this suggestion before, and while it would likely improve the sharpness, I'm one who thinks that if a lens is F/2.8 and has the L label, it should actually work at f/2.8.

Gochugogi wrote:
If it was me, I'd shoot at F4 or F5.6 for increased DOF. In this light you still have plenty of headroom for a fast shutter speed.

Edited on Nov 08, 2009 at 06:40 PM · View previous versions

Nov 08, 2009 at 06:28 PM

walter23
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p.2 #14 · Am I asking too much of a 50d plus 70-200 f/2.8

I think you misunderstand what I mean, I wasn't talking about "crop factor". DOF is not an all-or-nothing thing; it deends on print size, because there really is only one distance where things are truly sharp at any magnification. At other distances, whether or not it is sharp depends on how closely you are looking. If you print a slightly blurry image to a 2x3" print size, or look at it on your small camera's LCD, you won't see the blur, thus everything is "in the DOF". But suddenly if you look at an 8x10" print, or "100% view" on the monitor, the blur shows up and it's magically "out of the DOF".

DOF calculators assumes a standard *print* size, which is what I'm talking about here. If you look at the original image (not the full size one, just the resized one) it looks reasonably sharp. It would look sharper if she were actually in true focus, but she's still within DOF, though just at the edge of it because you can start to pick up some softness (e.g. in her leg).

DOF doesn't mean *in focus*, it means *looks sharp at standard print size*. Thus DOF calculators really should include print size & viewing distance in their calculations. Instead they usually just assume 8x10 print at arms length, or something like that, which falls apart if you're zooming in to 100% on your monitor.

volyrat wrote:
The DOF calculator does take into account that it is a 1.6 crop camera. Still says I've got 2 feet of DOF @ f/2.8.

walter23 wrote:
volyrat wrote:

The DOF calculator that I use says at 50 ft, 200mm, 1.6 crop and f/2.8, I should have about 2 feet of DOF- 1' in front and 1' behind.

With 2 feet of DOF, do you think that's the problem?

DOF calculations assume a standard print size. If you look at the standard web-sized version (your first image), she is sharp - within the DOF, albeit at the front edge of it (so not as razor sharp as she would look if she were truly in-focus). It's only when you start looking at magnified crops that you see where focus falls off. If you're going to be scrutinizing at 100%, you need to adjust your DOF calculation to account for the increased magnification.

Edited on Nov 08, 2009 at 06:45 PM · View previous versions

Nov 08, 2009 at 06:36 PM

Fat Dave
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p.2 #15 · Am I asking too much of a 50d plus 70-200 f/2.8

It should be significantly sharper, even at f/2.8. I shot the 70-200 2.8 IS with the 50D for many months, often wide open, and I know this combo can accurately track and sharply focus at 2.8 in most circumstances.

I agree with the comments of others above - the camera may have been struggling to focus on the low-contrast navy uniform in the shadow. I think if you focus on the high-contrast jersey, you'll get much better results. Zoom out a bit and crop subsequently if that will provide you with the framing that you want.

Nov 08, 2009 at 06:42 PM

volyrat
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p.2 #16 · Am I asking too much of a 50d plus 70-200 f/2.8

This one does look like the grass behind her feet could be in focus - like I said I never really trust grass because it is tough to discern sharp from not sharp.

Re: moving toward vs. sideways - I hadn't heard that, but will do some research. Thanks.

Re: low contrast - the example I showed was in the all blue area, but I've got the same problem when focused on the letters (white on blue) and one that's even got the little white logo right above the letters dead center in the focus point. It's small but with the letters right below it and her face right above it, I'd think there was enough contrast there.

This will be my 6th year of Nutcracker, so for better or worse I know exactly where she'll be and when. But yes, picking times when they pause is better. They are in the same auditorium all of the time so I also know where the brighter parts of the stage are.

And it is Franklin MA - been here for about 12 years.

patriot wrote:
Looking at the one image you posted, would have to agree with others here that the focus does seem to be just behind your daughter's feet. Canon should have calibrated to factory specs when you sent everything back. That lens will be a little soft at either end, wide open. That said, and as someone else pointed out, you may want to consider MA wide open at 200mm if that's where you shoot a lot.

You've also got your daughter running towards you. You said you were in al servo. Target moving directly away or towards you is, I believe, most difficult for Al servo, which is better with targets moving sideways. And clothing is not always high contrast, even if there are numbers, like on her shirt. Soccer shirts are often shiny, therefor reflective, which can appear as lower contract to the AF, especially compared to sharp contrast like the grass. One suggestion to try: using Al Focus, have your daughter run towards you at the same speed. The AF may be able to do a better job with the subject running directly towards in Al Focus.

For dance, like Nutcracker, she is more likely to be moving side to side. My daughter does a lot of dance and theater. Look for the stationary moments in the scene she is in when you can. If there is lighting, you may be able to get faster shutter speeds in better lighted scenes. I mostly use Al Focus in dance.

Is that "Franklin" as in Mass?

volyrat wrote:
Dave - thanks for the response.

Agreed that I could close down the aperture in this circumstance, but what happens in 4 weeks when I'm taking shots of her in a moderately lit auditorium as she dances in the Nutcracker? I'll be at 1600 or 3200 and still only get 1/500 or so - at best.

Second, I struggle with saying grass is sharp or not sharp - I'm looking for logos, letters or something else. I've looked at the 400 or so captures from today and the focus just isn't consistent. Even 3-4 frames into a burst, when all have 9+ spotting of the focus point, I get front, back and non focus. The only thing I don't get is sharp.

And re: Micro Adjust etc - I'd be OK with this if I hadn't spent 3 weeks trying it myself, then finally sending to Canon to let them figure it out, and having them send it back in this condition. Just not acceptible.

davenfl wrote:
I share your frustration and the frustration of anyone who has focus issues with their equipment. First lets talk about your exposure setup. Per the EXIF your shooting at 200mm wide open , 2.8. That is not providing you with any margin for error at all. In these lighting conditions you could well afford to drop your ISO from 200 to 100 and shoot AV with a maximum aperture of f5.6 or less, you will still have plenty of shutter speed to stop this motion and hopefully you will end up with a bunch of shots are f4 or f8 which will give you some depth of field. I copied your full size jpeg into CS4 and took a hard look at it. A line of grass just behind her feet is clearly in focus so you need to spend some time with a static set of objects on which you can get some microadjustment done. If you shoot a lot at 200mm then MA the lens there. MA and zooms don't necessarily mix well because the focus will shift as you change the focal length but with a 70-200 and smaller f-stops you should be alright. I wish I was there to help you but it is going to be ok, really. Some exposure work, some MA, and some patience and it will work.

Dave

Nov 08, 2009 at 07:29 PM

patriot
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p.2 #17 · Am I asking too much of a 50d plus 70-200 f/2.8

FSPA? If so, I might be there. I have the same lens as well as a 50D if you want to try a another lens.

volyrat wrote:
This one does look like the grass behind her feet could be in focus - like I said I never really trust grass because it is tough to discern sharp from not sharp.

Re: moving toward vs. sideways - I hadn't heard that, but will do some research. Thanks.

Re: low contrast - the example I showed was in the all blue area, but I've got the same problem when focused on the letters (white on blue) and one that's even got the little white logo right above the letters dead center in the focus point. It's small but with the letters right below it and her face right above it, I'd think there was enough contrast there.

This will be my 6th year of Nutcracker, so for better or worse I know exactly where she'll be and when. But yes, picking times when they pause is better. They are in the same auditorium all of the time so I also know where the brighter parts of the stage are.

And it is Franklin MA - been here for about 12 years.

patriot wrote:
Looking at the one image you posted, would have to agree with others here that the focus does seem to be just behind your daughter's feet. Canon should have calibrated to factory specs when you sent everything back. That lens will be a little soft at either end, wide open. That said, and as someone else pointed out, you may want to consider MA wide open at 200mm if that's where you shoot a lot.

You've also got your daughter running towards you. You said you were in al servo. Target moving directly away or towards you is, I believe, most difficult for Al servo, which is better with targets moving sideways. And clothing is not always high contrast, even if there are numbers, like on her shirt. Soccer shirts are often shiny, therefor reflective, which can appear as lower contract to the AF, especially compared to sharp contrast like the grass. One suggestion to try: using Al Focus, have your daughter run towards you at the same speed. The AF may be able to do a better job with the subject running directly towards in Al Focus.

For dance, like Nutcracker, she is more likely to be moving side to side. My daughter does a lot of dance and theater. Look for the stationary moments in the scene she is in when you can. If there is lighting, you may be able to get faster shutter speeds in better lighted scenes. I mostly use Al Focus in dance.

Is that "Franklin" as in Mass?

volyrat wrote:
Dave - thanks for the response.

Agreed that I could close down the aperture in this circumstance, but what happens in 4 weeks when I'm taking shots of her in a moderately lit auditorium as she dances in the Nutcracker? I'll be at 1600 or 3200 and still only get 1/500 or so - at best.

Second, I struggle with saying grass is sharp or not sharp - I'm looking for logos, letters or something else. I've looked at the 400 or so captures from today and the focus just isn't consistent. Even 3-4 frames into a burst, when all have 9+ spotting of the focus point, I get front, back and non focus. The only thing I don't get is sharp.

And re: Micro Adjust etc - I'd be OK with this if I hadn't spent 3 weeks trying it myself, then finally sending to Canon to let them figure it out, and having them send it back in this condition. Just not acceptible.

davenfl wrote:
I share your frustration and the frustration of anyone who has focus issues with their equipment. First lets talk about your exposure setup. Per the EXIF your shooting at 200mm wide open , 2.8. That is not providing you with any margin for error at all. In these lighting conditions you could well afford to drop your ISO from 200 to 100 and shoot AV with a maximum aperture of f5.6 or less, you will still have plenty of shutter speed to stop this motion and hopefully you will end up with a bunch of shots are f4 or f8 which will give you some depth of field. I copied your full size jpeg into CS4 and took a hard look at it. A line of grass just behind her feet is clearly in focus so you need to spend some time with a static set of objects on which you can get some microadjustment done. If you shoot a lot at 200mm then MA the lens there. MA and zooms don't necessarily mix well because the focus will shift as you change the focal length but with a 70-200 and smaller f-stops you should be alright. I wish I was there to help you but it is going to be ok, really. Some exposure work, some MA, and some patience and it will work.

Dave

Nov 08, 2009 at 07:50 PM

Bearmann
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p.2 #18 · Am I asking too much of a 50d plus 70-200 f/2.8

I think the combo needs to go back to Canon for another look. That being said, didn't I read somewhere that the Canon cameras (perhaps not the pro series) don't continue to focus in burst mode? I think it only focuses on the first frame of the burst, not the subsequent ones. So if the subject is moving toward the center of the DOF, then all is good, but if the subject is moving away from the center of the DOF, the each additional shot will be worse. It might be worth a try to take it out of burst mode and see what you get.

Barry

Nov 08, 2009 at 08:07 PM

Andrew Reid
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p.2 #19 · Am I asking too much of a 50d plus 70-200 f/2.8

Bearmann wrote:
That being said, didn't I read somewhere that the Canon cameras (perhaps not the pro series) don't continue to focus in burst mode? I think it only focuses on the first frame of the burst, not the subsequent ones.
Barry

That's true for 'One-Shot' auto-focus, but not for 'AI-Servo' where the camera tracks (tries to predict focus) and adjusts the focus between shots.

Nov 08, 2009 at 09:23 PM

walter23
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p.2 #20 · Am I asking too much of a 50d plus 70-200 f/2.8

Andrew Reid wrote:
That's true for 'One-Shot' auto-focus, but not for 'AI-Servo' where the camera tracks (tries to predict focus) and adjusts the focus between shots.

The key words there are "tries to predict focus".

Prediction is prone to error. You'd probably get best results with AI-Servo on something like a racecar moving towards you at fairly uniform speed.

Nov 08, 2009 at 09:28 PM

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p.2 #21 · Am I asking too much of a 50d plus 70-200 f/2.8

walter23 wrote:
Andrew Reid wrote:
That's true for 'One-Shot' auto-focus, but not for 'AI-Servo' where the camera tracks (tries to predict focus) and adjusts the focus between shots.

The key words there are "tries to predict focus".

Prediction is prone to error. You'd probably get best results with AI-Servo on something like a racecar moving towards you at fairly uniform speed.

Indeed. I tried AI Servo with my 5D on dogs that were moving around a little, but not a lot and the camera managed to back and front focus quite frequently.

Nov 08, 2009 at 10:16 PM

DrScott
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p.2 #22 · Am I asking too much of a 50d plus 70-200 f/2.8

More random thoughts from someone who really doesn't know anything: I believe I read somewhere - possible on these forums - that cameras and lenses sent to Canon will be calibrated back to "within range" rather than calibrated to each other. So even after getting them back from Canon there might still be some work to be done with MA to achieve the best focus.

Best of luck getting it sorted.

S.

Nov 08, 2009 at 10:47 PM

volyrat
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p.2 #23 · Am I asking too much of a 50d plus 70-200 f/2.8

Yes on FSPA - my oldest is a Maid, Big Mouse and Polychennel (sp?).

My little one (in the original picture) was supposed to be an Angel but rehearsal time conflicted with Saturday game time, so she opted for soccer.

I'll send you a PM, as I'm sure I've just completely confused 99.9% of the FM readers...

patriot wrote:
FSPA? If so, I might be there. I have the same lens as well as a 50D if you want to try a another lens.

volyrat wrote:
This one does look like the grass behind her feet could be in focus - like I said I never really trust grass because it is tough to discern sharp from not sharp.

Re: moving toward vs. sideways - I hadn't heard that, but will do some research. Thanks.

Re: low contrast - the example I showed was in the all blue area, but I've got the same problem when focused on the letters (white on blue) and one that's even got the little white logo right above the letters dead center in the focus point. It's small but with the letters right below it and her face right above it, I'd think there was enough contrast there.

This will be my 6th year of Nutcracker, so for better or worse I know exactly where she'll be and when. But yes, picking times when they pause is better. They are in the same auditorium all of the time so I also know where the brighter parts of the stage are.

And it is Franklin MA - been here for about 12 years.

patriot wrote:
Looking at the one image you posted, would have to agree with others here that the focus does seem to be just behind your daughter's feet. Canon should have calibrated to factory specs when you sent everything back. That lens will be a little soft at either end, wide open. That said, and as someone else pointed out, you may want to consider MA wide open at 200mm if that's where you shoot a lot.

You've also got your daughter running towards you. You said you were in al servo. Target moving directly away or towards you is, I believe, most difficult for Al servo, which is better with targets moving sideways. And clothing is not always high contrast, even if there are numbers, like on her shirt. Soccer shirts are often shiny, therefor reflective, which can appear as lower contract to the AF, especially compared to sharp contrast like the grass. One suggestion to try: using Al Focus, have your daughter run towards you at the same speed. The AF may be able to do a better job with the subject running directly towards in Al Focus.

For dance, like Nutcracker, she is more likely to be moving side to side. My daughter does a lot of dance and theater. Look for the stationary moments in the scene she is in when you can. If there is lighting, you may be able to get faster shutter speeds in better lighted scenes. I mostly use Al Focus in dance.

Is that "Franklin" as in Mass?

volyrat wrote:
Dave - thanks for the response.

Agreed that I could close down the aperture in this circumstance, but what happens in 4 weeks when I'm taking shots of her in a moderately lit auditorium as she dances in the Nutcracker? I'll be at 1600 or 3200 and still only get 1/500 or so - at best.

Second, I struggle with saying grass is sharp or not sharp - I'm looking for logos, letters or something else. I've looked at the 400 or so captures from today and the focus just isn't consistent. Even 3-4 frames into a burst, when all have 9+ spotting of the focus point, I get front, back and non focus. The only thing I don't get is sharp.

And re: Micro Adjust etc - I'd be OK with this if I hadn't spent 3 weeks trying it myself, then finally sending to Canon to let them figure it out, and having them send it back in this condition. Just not acceptible.

davenfl wrote:
I share your frustration and the frustration of anyone who has focus issues with their equipment. First lets talk about your exposure setup. Per the EXIF your shooting at 200mm wide open , 2.8. That is not providing you with any margin for error at all. In these lighting conditions you could well afford to drop your ISO from 200 to 100 and shoot AV with a maximum aperture of f5.6 or less, you will still have plenty of shutter speed to stop this motion and hopefully you will end up with a bunch of shots are f4 or f8 which will give you some depth of field. I copied your full size jpeg into CS4 and took a hard look at it. A line of grass just behind her feet is clearly in focus so you need to spend some time with a static set of objects on which you can get some microadjustment done. If you shoot a lot at 200mm then MA the lens there. MA and zooms don't necessarily mix well because the focus will shift as you change the focal length but with a 70-200 and smaller f-stops you should be alright. I wish I was there to help you but it is going to be ok, really. Some exposure work, some MA, and some patience and it will work.

Dave

Nov 09, 2009 at 01:56 AM

volyrat
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p.2 #24 · Am I asking too much of a 50d plus 70-200 f/2.8

I'm having a bit of a battle with Canon right now regarding sending it in again. Basically I got the "just stop it down, it will be fine" email. If that's the case, I'll sell the 2.8 and go back to an f/4.

I tried low burst today (rather than H burst) and we'll see how that worked out.

BTW, today was the example of why I want f/2.8 to work. A 3:15p game time - golden hour light but at f/5.6 (had a 1.4 tc plus stopped down) at ISO 1600 I got shutter speeds of 1/800. Sometimes fast enough, but barely on the edge. At f/2.8, I would've had excellent lighting at the correct shutter speeds and a decent ISO.

The last paragraph isn't specific to your post but many others suggesting "stopping down" as an alternative.

Bearmann wrote:
I think the combo needs to go back to Canon for another look. That being said, didn't I read somewhere that the Canon cameras (perhaps not the pro series) don't continue to focus in burst mode? I think it only focuses on the first frame of the burst, not the subsequent ones. So if the subject is moving toward the center of the DOF, then all is good, but if the subject is moving away from the center of the DOF, the each additional shot will be worse. It might be worth a try to take it out of burst mode and see what you get.

Barry

Nov 09, 2009 at 02:07 AM

volyrat
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p.2 #25 · Am I asking too much of a 50d plus 70-200 f/2.8

Maybe true on calibration. Long ago, I did send a 17-40 f/4 and Rebel XT to canon and got great results after their calibration. Maybe my expectations are high, but in that instance it really worked well.

thanks for the message.

DrScott wrote:
More random thoughts from someone who really doesn't know anything: I believe I read somewhere - possible on these forums - that cameras and lenses sent to Canon will be calibrated back to "within range" rather than calibrated to each other. So even after getting them back from Canon there might still be some work to be done with MA to achieve the best focus.

Best of luck getting it sorted.

S.

Nov 09, 2009 at 02:11 AM


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