7D fast burst in MF but slows considerably in AF

so i searched for threads concerning how the 7D doesnt get the full 8fps advertised and even the last soccer game i shot using direct sunlight i was getting like 2fps in AF servo mode. all my settings were pretty much default: single center AF spot focus, AF servo, evaluative metering

now when i set my camera to MF why am i getting like 3 times the fps in continuous. just testing it out in my room on bottles on my desk. in MF im getting probably like 6 maybe. i would like to get at least 6 fps while using auto focus shooting sports. if i cant get the full 8 it wont kill me but it stinks not taking full advantage of what im supposed to get

AI servo mode needs time to "hunt" for the moving target? Manual focus will fire regardless. I'm just guessing.

i guess i need to test it outside in the sun maybe it is servo. because in single shot focus it shoots pretty fast. dont have a stop watch to test.

i guess my question is whether its possible to get 8fps in servo since 8fps would be used for sports when servo is also being used. i would assume this for most situations

See the warning box on the bottom of page 93 in the 7D manual. It says that in AI Servo certain lens and subject combinations will cause the fps decrease. It doesn't really explain why but I'm sure it has to do with acquiring focus and if certain in-camera processing options are enabled.

I was trying to take a pic of a friend's dog catching a ball a while ago, and was using the canon 50mm f/1.4 because it was indoors (light was decent).

Burst was slow because of AF and trying to quickly follow (panning) the dog. I thought it was the low light burst issue, but it turned out it was simply the AF not being quick enough to focus.

That said, what lens were you using? Does your lens have USM or equivalent?

yea i am using USM lenses. and was testing on a sigma 30 which has their USM equivalent

even my 50 1.8 got fast fps shooting basketball in servo. its been a while since i shot fast burst

i guess even then, the type of USM in the lens does matter.

The 50mm f/1.4 that I have doesn't have Ring USM, which I believe is better than the micro USM the 50 has.
My 70-300 IS also has USM, but again, doesn't have Ring USM, which means it's a little slow to focus (feels a lot slower than my 15-85) and has no full time manual.

I don't really know much about the sigma...

the sigma is pretty quick to focus unless super low light which is pretty much all lenses have trouble in really low light

Brian, I don't have a 7D, don't ask me about a Holiday Express, but I do have a 1DMk3. And, since the 7D has adopted an advanced AF system with similarities to the 1D3 AF, there are some things that you want/need to get familiar with.

These things are settings that determine how the AI Servo AF will function. In other words, as you have seen, AI Servo AF does slow down the fps of continuous shooting, this is normal, but you can actually use settings in your camera that can moderate that behavior.

So, these settings are in the Custom Functions. At this point it could be appropriate to ask "have you read the dang manual?". I ask not to make you feel silly, but to alert you to the fact that manuals give you important, needed information, and especially a camera like the 7D with complexities that go beyond those of more "familiar" features will have info covering those complexities. But also, maybe you have read the manual and are familiar with these things and I'm wasting my breath.

Well, in a nutshell, you need to take the time to go over the camera settings for C.Fn III. You can find these described starting on page 209 in your camera manual. There are quite a few settings, and I won't take the time to spell them out and repeat the descriptions from the manual. If you read those descriptions you should be able to see how they can matter, and how for some scenarios one setting would be more useful than another.

Read over this section carefully, heck read it over a couple times carefully until you get a good "overview" of things, then it is time to grab your camera. Choose a setting at a time and use it while doing some shots. Then choose a combination of two or more settings and play with them.

Really, they will make a difference! My 1D3 has a max spped of 10 fps, but honestly I set my max to 6, which is great for almost any use I need it for. Occasionally I up it, but not very often.

And, in AI Servo AF, I don't see a slowdown from that setting, and that body is set to AI Servo pretty much all the time, and the lens/TC combo I mostly use on it is not what you would consider the "fastest" for AF. Of course if I just use the 70-200 f/2.8 IS, which I prefer for sports, the AF is both snappy and responsive and accurate and so, if anything, the fps would show some improvement, but really not much that I can tell.

So, do your homework and then get to shooting and get back to us with your results!!!

Check your manual, find the part about shutter priority vs. Focus priority and set as you prefer.

i have played with the settings. i think it was the result of the battery being at half charge. apparently when the battery isnt fully charged that affects fps. although it was at like 40% which is still plenty of juice imo

Um,no. The only time I ever saw that impact was batteries just about to die entirely.

The amount of light, haze, contrast, and the quality of the lens are more likely to impact FPS IMO.

idk but i just finished charging my batteries and now my fps is back to normal at probably like 7 fps

Brian_R wrote in post #13038353
idk but i just finished charging my batteries and now my fps is back to normal at probably like 7 fps

Well, there you go! You did better than all of us combined!

Since the 7D does manage to reach 8 frames/s on the relatively small battery it has, it also makes it vulnerable to battery discharge, when it comes to maintaining the frame rate.
If you use a battery grip with two batteries inside, it works better. The camera still runs from one battery at a time, but it alternates between them, using the one that's best at the moment. While doing that, the other one rests, which means you'll for a longer time have a battery at hand that can provide enough power to achieve the full frame rate.