EOS 5D mark III FPS drop

[jmyoungs30]

Hey all, 

I am having an issue with my 5D Mark III. When my batteries get down to 50%, my high-speed burst mode goes from 6FPS down to about 3FPS and will not exceed that until I put new batteries in. It's not like the batteries are dead as the camera clearly indicates that they have 50% of their life remaining. Buddy of mine thinks it's a battery efficiency problem, or he also thinks that it may be doing that because of a camera setting that requires is to drop in speed to maintain battery life. Checked the manual and the camera settings, No indication on why it's doing this. Any input is welcome. 

It's weird because it works just fine otherwise, but as soon as it hits exactly 50%, it drops instantly. I am using a battery grip with 2 batteries installed, so if anything it should help the camera out I would think. 

[Waddizzle]

Try a fresh set of genuine Canon batteries.  The behavior could just very well be by design, to preserve battery life.

I also suggest removing the grip, just to see if the problem persists without it.  I am not sure how much difference it would make, though.  Based on my observations, battery grips seem to alternate between the batteries, which causes them to discharge at close to the same rate.  The camera is only using one battery at all times, grip or no grip.

[wq9nsc]

As batteries age, one of the characteristics that changes most it the ability to sustain proper voltage under a sustained load.  As your burst rate goes up, the battery voltage is sagging under load and when that happens the frame rate will drop.  You will need a new set of batteries AND you will also find that some of the third party replacements from the start don't have the sustained current capability of the Canon cells and will show this reduced frame rate more quickly.

I use the older Canon ACK-E4 AC adapter pack with both my 1DX and 1DX Mark II bodies and when using the older adapter to power the Mark II it drops the maximum frame rate from 14 down to 8 FPS which is basically what is happening when your older batteries hit their current/voltage "knee" in your 5D3.

Rodger

[RobertTheFat]

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@wq9nsc wrote:

As batteries age, one of the characteristics that changes most it the ability to sustain proper voltage under a sustained load.  As your burst rate goes up, the battery voltage is sagging under load and when that happens the frame rate will drop.  You will need a new set of batteries AND you will also find that some of the third party replacements from the start don't have the sustained current capability of the Canon cells and will show this reduced frame rate more quickly.

I use the older Canon ACK-E4 AC adapter pack with both my 1DX and 1DX Mark II bodies and when using the older adapter to power the Mark II it drops the maximum frame rate from 14 down to 8 FPS which is basically what is happening when your older batteries hit their current/voltage "knee" in your 5D3.

Rodger

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So what's the underlying theory? That the older adapter, like the Brand X batteries, lacks the current capacity to supply the power necessary to sustain the higher frame rate?

[wq9nsc]

RobertTheFat wrote:

"So what's the underlying theory? That the older adapter, like the Brand X batteries, lacks the current capacity to supply the power necessary to sustain the higher frame rate?"

Bob,

That is correct.  As batteries age, their ability to deliver high current decreases while internal resistance increases causing a voltage drop. As the voltage drops processors will go from their full speed capability to a slower speed just as current pad and notebook computers will reduce CPU voltage to prolong battery life during light processor load conditions.  At some point this rapid change from normal to greatly reduced voltage can cause camera errors.

At one point I bought a pair of aftermarket batteries for my 1D Mark II and sustained bursts in high speed mode would frequently cause the camera to lock up requiring battery removal to restart it. You could see the battery level drop from full to near depleted during a burst and then it would climb back up after the burst mode.  I replaced these with a pair of real Canon batteries and the problem went away.  I later measured the Canon vs aftermarket under heavy load and the voltage drop was much greater under sustained load with the after market batteries.  These same batteries worked fine in single shot mode or for short bursts.

You will see the same issue happening when batteries get very cold which can cause a huge drop in performance as I found out Thursday during the "perfect storm".  My daughter's soccer conditioning ended early and just as I went to open the garage door for the detached garage I use for my 4WD pickup the power failed.  I never bothered (foolishly) putting a separate door for that garage and when the power failed I had to crawl through a window to manually release the garage door opener. I briefly set my iPhone down on the driveway so it wouldn't fall out during my spiderman through the window imitation and it went from 40% to no usable charge during the 5 minutes it took as the iPhone sat out in -4F conditions.  Lesson learned and I installed a locking cable release for that garage so that a power failure won't be a problem again.  The Corvette and rear wheel drive Cadillac were in the other garage but neither would work well on ice intermixed with deep snow drifts. At that point a slow camera would have seemed like a very minor issue.

Rodger

[jmyoungs30]

Here's the thing. I have this exact issue with 1-year-old canon batteries and brand new third party batteries. It's not like it's restricted to one thing. I have never tried it without the grip and I will probably, just to try and rule everything out. 

[kvbarkley]

What does the buffer indicator in the viewfinder say?

[ebiggs1]

"I am using a battery grip with 2 batteries installed, so if anything it should help the camera out I would think."

First thought is, are you using a Canon brand grip and Canon brand batteries?  If no, that is the problem.  Put a real Canon battery in the camera without the grip installed and try it.

Make sure your charger is working and it is a real Canon brand, too.