What on earth is going on? (A bit of an emergency)

C.Fn III.2 has four settings for each combination of:

AF Priority vs Drive Priority
and
Tracking Priority vs Drive Speed Priority

It is the latter pair that can affect your burst rate. If you have it set to Tracking Priority (settings 0 or 3) then shots after the first one will be taken only when the subject should be in focus. In Drive Speed Priority it will always shoot at the maximum possible burst rate regardless of whether anything is in focus or not.

When using Servo AF, the camera has to carry out at least one focusing operation between each shot. Otherwise it would not track focus, which is exactly what Servo AF is all about.
Now it shouldn't be too much of a surprise that to do the metering, evaluation and focus drive of the lens takes at least some time, even if the camera is quick.
Compare that to using manual focus, where none of these events, i.e. metering focus situation, evaluation and lens drive has to occur.

Which do you think take longest, do something or do nothing?

Now the 7D is designed in such a way, that in good conditions it has enough capability to actually execute all the AF related tasks in between two shots, even in high speed continuous. But this takes that the subject has a reasonable contrast somewhere, that the lighting is such that this contrast is bright enough and that you, the photographer, manages to keep an active AF point on the target. If any of these conditions fail, then the camera operation will slow down. If you have it set to AF priority, which is the default, it will slow down more than if set at drive priority. In the second case, the risk you get an image out of focus increases instead. Sometimes a slightly dizzy image is better than no image at all. That's up to you to decide, hence the setting.

Note that under good conditions, you can't test the difference between AF and drive priority. Under good conditions, there is none, since then the camera is capable of doing everything it should even during the short time frame allocated to AF in drive priority, so there is no difference to see.

Noteworthy is also that for the camera to be able to measure focus, it needs a contrast. If the camera is shaking a lot, the contrast gets blurred on the AF sensor, and then evaluation is everything from slower to impossible. Using IS for action photo is kind of a double-edged sword. Although it sometimes ends up with lagging behind your intentional camera movement, and therefore causes blur instead of reducing it, if you take the picture when the camera is catching up with your movements, IS stabilizes not only the picture, but also the viewfinder. And since the AF sensor sees the same thing as you see, it also stabilizes the contrasts presented to the AF sensor. Which makes AF calculations faster, which in turn may keep drive speed up.
Now I notice that your lens doesn't have IS, so if it has any effect on your images, it's slowing down AF in that case. Since I've never seen you work, I can't tell if this is really something that happens, but when you know this, you have to make your own judgement about that.

Another issue is of course how many AF points you use, and to which degree you make them stay on target. I can't judge that either.

Finally, it's true that in really low light, the continuous drive speed of the 7D goes down to about four frames/s. But this is in such low light that in most cases you'll loose drive speed due to slow shutter speeds anyway. Count on that you have to use 1/500 s or faster for the camera to do its best.

hollis_f wrote in post #12147871
If you have it set to Tracking Priority (settings 0 or 3) then shots after the first one will be taken only when the subject should be in focus. In Drive Speed Priority it will always shoot at the maximum possible burst rate regardless of whether anything is in focus or not.

Almost right.
In AF priority, the camera will allocate more time for AF measurement/calculatio​ns between the shots, if it has to. In good conditions, there will be no difference, since then it's capable of doing this at full speed.
But even in AF priority, it extends the time to allow several attempts (Canon doesn't say how many), but not indefinitely. If a few attempts still doesn't lead to the camera knowing where the focus should be, it will fire anyway, and you'll get a picture with whatever focus happened to be.

In drive priority, the camera only does one attempt to measure and calculate focus position. Under difficult conditions, this will take longer time, so drive speed may still slow down somewhat, albeit less than in AF priority. Risk for an out of focus image increases.

In good light, with good contrast, there is no difference, since even in AF priority, the camera continues if one attempt at measuring and calculating was sufficient, so then there is no slowdown in any of the cases.

I never use "machine-gun mode", but I would suspect that having the camera's exposure mode dial set to anything but "M" would tend to slow down the burst rate just like forcing the camera to autofocus would. In addition, if you need to use 1/120 or 1/60 shutter speed to get around gas-discharge lighting issues, that would probably slow down the maximum burst rate.

M doesn't make any difference at all. The camera performs exposure metering in the same way regardless of which mode you use. In M it's just for you to have something to compare with, but that doesn't matter. The workload is the same, and it's neglectible compared to the AF and other stuff. Just make sure the shutter speed is above 1/250 s, preferably at 1/500 s or shorter.

As I stated above, if you give the camera good AF conditions, there is no slowdown due to servo AF. It has enough power to handle that.

Unrelated but GO BU (my alma mater)!!!

Good luck with your pics Monday.

Chances are good you're not nearly as stupid as me, but TWICE shooting with the 7D I thought I was shooting in continuous high-speed mode, but in reality, only shooting in continuous! Palm - face!

It happens!

Hope some of your shots of the tourney games came out well. Would like to see some after you process them.

dave

An interesting thread. Are you using single-spot focus? Would multi-spot focus increase the calculation time enough to affect the burst timing?

It can go either way. Obviously, more points means more things for the camera to evaluate, but more points also increases the chance that at least one of them has a good contrast to work with.
So it varies from case to case. Good contrast is easy to compute things from, so that's fast, but if all of them has crappy contrast, it will take longer for the camera to give up.

There's of course a reason that when using Servo AF with all points active, the 45 point 1D Mark IV reduces the number of actually used points to 19, which happens to be the same as the 7D has. But the 1D Mark IV then has at a few that aren't cross type, so the workload there is slightly less. On the other hand, the continuous drive speed is a bit higher, so perhaps that evens out.

Keyan wrote in post #12148484
Unrelated but GO BU (my alma mater)!!!

Good luck with your pics Monday.

HEY! I was just gonna post that no matter what happens, the OP'd better get mah Dawgs in focus!

Class of '86, here.

apersson850 wrote in post #12147872
When using Servo AF, the camera has to carry out at least one focusing operation between each shot. Otherwise it would not track focus, which is exactly what Servo AF is all about.
Now it shouldn't be too much of a surprise that to do the metering, evaluation and focus drive of the lens takes at least some time, even if the camera is quick.
Compare that to using manual focus, where none of these events, i.e. metering focus situation, evaluation and lens drive has to occur.

Which do you think take longest, do something or do nothing?

Now the 7D is designed in such a way, that in good conditions it has enough capability to actually execute all the AF related tasks in between two shots, even in high speed continuous. But this takes that the subject has a reasonable contrast somewhere, that the lighting is such that this contrast is bright enough and that you, the photographer, manages to keep an active AF point on the target. If any of these conditions fail, then the camera operation will slow down. If you have it set to AF priority, which is the default, it will slow down more than if set at drive priority. In the second case, the risk you get an image out of focus increases instead. Sometimes a slightly dizzy image is better than no image at all. That's up to you to decide, hence the setting.

Note that under good conditions, you can't test the difference between AF and drive priority. Under good conditions, there is none, since then the camera is capable of doing everything it should even during the short time frame allocated to AF in drive priority, so there is no difference to see.

Noteworthy is also that for the camera to be able to measure focus, it needs a contrast. If the camera is shaking a lot, the contrast gets blurred on the AF sensor, and then evaluation is everything from slower to impossible. Using IS for action photo is kind of a double-edged sword. Although it sometimes ends up with lagging behind your intentional camera movement, and therefore causes blur instead of reducing it, if you take the picture when the camera is catching up with your movements, IS stabilizes not only the picture, but also the viewfinder. And since the AF sensor sees the same thing as you see, it also stabilizes the contrasts presented to the AF sensor. Which makes AF calculations faster, which in turn may keep drive speed up.
Now I notice that your lens doesn't have IS, so if it has any effect on your images, it's slowing down AF in that case. Since I've never seen you work, I can't tell if this is really something that happens, but when you know this, you have to make your own judgement about that.

Another issue is of course how many AF points you use, and to which degree you make them stay on target. I can't judge that either.

Finally, it's true that in really low light, the continuous drive speed of the 7D goes down to about four frames/s. But this is in such low light that in most cases you'll loose drive speed due to slow shutter speeds anyway. Count on that you have to use 1/500 s or faster for the camera to do its best.

Thank you for the explanation. It seemed as if I was losing FPS due to the lens re-focusing on subjects at different distances. I wish it would pull focus faster.

snyderman wrote in post #12148613
Chances are good you're not nearly as stupid as me, but TWICE shooting with the 7D I thought I was shooting in continuous high-speed mode, but in reality, only shooting in continuous! Palm - face!

It happens!

Hope some of your shots of the tourney games came out well. Would like to see some after you process them.

dave

Yeah, high speed all the way, I double checked. If it weren't for the grip you sold me, this task would have been a real pain!

bubbygator wrote in post #12148811
An interesting thread. Are you using single-spot focus? Would multi-spot focus increase the calculation time enough to affect the burst timing?

I'm using single spot with expansion.

I don't know about the Transcend 400X card that OP is using.... I'm guessing it's UDMA, and probably fast enough....

But recently I happened across another brand of memory card that claimed 300X or 400X (45MB/sec or 60MB/sec) and UDMA... But turned out that was the card's read speed, not it's write speed, which was actually more like 80X or 100x, 15MB/sec. I passed, even though the price was good!

Also be sure you haven't accidentally selected Spot Focus mode on 7D. That't the higher accuracy AF mode that shows the small box inside the larger box on the AF sensor display in the viewfinder. Spot Focus is definitely slower.

And be sure you haven't accidentally selected AI Focus instead of AI Servo. That's also slower.

If either of the above is set and CFn III-2 is set to 0, then the camera will prioritize accurate focus over drive speed, so often will slow down bursts. Set this CFn to 1 and the first shot is focus priority, but all the subsequent shots in a burst are drive speed priority. Set it to 2 and all shots are drive speed priority. In option 3, the first shot is given drive speed (release) priority over focus accuracy, but all subsequent burst shots are given focus accuracy priority.

So, in a sense you have to choose between focus accuracy and max drive speed. Personally I'd go with focus accuracy... But I try to avoid a lot of high speed bursts anyway... That makes for a whole lot more images to edit, and I think in most situations I get as good or better results carefully timing single shots and not relying on "spray and pray".

CFn II-2 High ISO Noise Reduction set to 2. "strong" will reduce the number of images that can be buffered a lot, so will slow down long bursts a lot whenever the buffer is full.

CFn IV-3 Add Image Verification Data might slow things down a little if enabled.

I think some other things that can slow bursts, in addition to what's been noted by others, are Auto Lighting Optimizer (enable/disable in Menu) and Highlight Tone Priority (enable/disable in CFn. II-3).

I think it's most accurate to focus with a single point (combined with Back Button Focusing)... Don't use expansion points and leave it to the camera to choose. By using BBF, my shot is in focus and I'm already tracking the subject before I press the shutter button to take a shot.

As for metering and re-metering between shots, particularly if working indoors in a well lit, evenly lit arena, simply switch to M and lock in your ISO, shutter speed and aperture. If the lighting is reasonably even, there's no need for auto exposure modes making constant adjustments. This should help avoid any possible slowdowns for metering.

I think there might be a minimum shutter speed, too. I just don't recall what it is for max burst speed. Maybe 1/250? I think in the EXIF I saw you were using Av mode... are you sure the shutter speeds were high enough? Using M and setting everything in advance, there's no chance of too low a shutter speed being selected. Or use Tv and set it yourself (but then you have to hope that too large an aperture isn't used, resulting in too shallow Depth of Field).

Yes, on the court I tried to keep it above 1/500, 1/400 at the minimum. Sometimes the subjects would move so fast than there was minor motion blur at 1/800.

Everything was disabled. High ISO noise reduction, auto lighting optimizer and highlight tone priority. I don't really believe in those features anyway.

amfoto1 wrote in post #12150198
I don't know about the Transcend 400X card that OP is using.... I'm guessing it's UDMA, and probably fast enough....

Doesn't really matter as burst speed is independent of card speed until the buffer is filled.

newton wrote in post #12150418
High ISO noise reduction, auto lighting optimizer and highlight tone priority. I don't really believe in those features anyway.

Doesn't matter. Most of these things don't affect high speed shooting, although many seem to believe so.

Also, the categorical advise not to use expansion points can be both good or bad, as I told you earlier.
Now you indicated that the camera frequently focused on other things than the main target. What setting did you have for C.Fn III-1? Thinking about it, list the settings for number 2, 3 and 4 in that group too.
Then please post some pictures, so we can see what it looks like when you are shooting. Our advice is less accurate if they don't fit your situation.