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Gear Talk => Technical Support => Topic started by: phoizen on May 25, 2013, 02:43:05 AM

Title: 5dm3 - FPS Drops when battery below 50%
Post by: phoizen on May 25, 2013, 02:43:05 AM
Hello to anyone reading. Long time reader first time poster! Managed to find every answer I ever needed by searching. However, this problem I could not find a specific answer to. If it has been posted before could someone please refer a link for me?

Problem: When my battery level drops below 50% the 5dM3 FPS rate drops to about half as fast. I have the shooting mode on High Speed Continuous. Have tested 4 different battery's, tried it with and without the grip, and also tested on my second 5dm3 body. Results are the same across the board. Even with the grip and two battery's inserted, when BOTH battery's fall below 50% the FPS will drop.

Anyone have any clue on why? Swear it wasn't doing this the first 5 months I've shot with it. Any help would be greatly appreciated! Thanks.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: M.ST on May 25, 2013, 03:26:24 AM
The FPS drops before the battery is below 50 %.

I reported this problem in November 2011 to Canon.

You can nothing do against it.

The main problem is that Canon use the old battery from the Mark II and 7D in the Mark III and dont bring a new more powerfull battery on the market.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Skulker on May 25, 2013, 04:33:06 AM
When a battery goes flat it has less power, so it is reasonable to expect things to slow down. To maintain the same speed on less voltage you would need more current, that could give serious problems. Sounds like a safety feature to me. Bigger batteries would mean a heavier camera.

There are 2 obvious solutions. 1 get a grip with second battery or get spares. Seems you have done both. If you really need the speed for so many shots and can't change batteries then you could up grade your camera. A 1Dx would be my choice.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: sanj on May 25, 2013, 07:22:22 AM
I have not noticed this problem. Hmmmm.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: phoizen on May 25, 2013, 01:54:49 PM
Thanks for the input! I see I'm not alone.

I have tried brand new battery's and still same issue. However I seriously do not recall this occurring during the first few months of use. I wonder, would it help to use the AA pack in the grip?

Mostly on the wedding scene, so it's nice to run the battery's down over a couple days shooting. Otherwise you start with good FPS, then halfway through the shoot it drops. =/

Going to update firmware and give the AA cradle a shot. See whats what.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Skulker on May 25, 2013, 06:08:26 PM
Thanks for the input! I see I'm not alone.

I have tried brand new battery's and still same issue. However I seriously do not recall this occurring during the first few months of use.

so it's nice to run the battery's down over a couple days shooting.


Try reading the manual you may find that the "issue" is perfectly normal. If you don't find that then try reading page 113  :-[   If you had something like a remote control car would you really complain about an "issue" if it ran slower when the batteries were flat?

As you didn't notice this normal behavior for the first few months it sounds like its not really such a problem.

Why on earth is it "nice to run the battery's down over a couple of days"? Are you trying to make the "issue" worse?
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Camerajah on May 25, 2013, 07:59:15 PM
the manual says to charge the battery the day before or on the day of usage.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: can0nfan2379 on May 25, 2013, 08:13:11 PM
As Skulker mentioned, this is perfectly normal for the 5D3.

Just as a side note though, I never recalled my 7D ever slowing down even with 10-20% battery left.

Does anyone know -- is it the fact that the mirror is simply larger (being full frame as opposed to crop) and there is more mass to move with insufficient voltage/current accounting for the slowdown? Just curious.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: TAF on May 25, 2013, 08:34:55 PM

Mostly on the wedding scene, so it's nice to run the battery's down over a couple days shooting. Otherwise you start with good FPS, then halfway through the shoot it drops. =/


Why do you think it is nice to run the batteries down?  It isn't.  Li-Ion batteries are better off being used partially and then recharged.  These aren't the olden days of NiCd's.

See Table 2 at:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries (http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries)

Sounds to me like you just need to keep some spare charged batteries on hand, and swap them out when you notice the speed drop.

I'll have to try and see if I have the same experience - I normally never let my batteries fall below 50% so as to maximize lifetime and to ensure that UI never run out of power at an inopertune moment, so it will be a new experience.

Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: fegari on May 25, 2013, 08:55:08 PM
I do not know what kind of energy the Grip's battery provide but maybe if someone reading this post has the following battery and can comment on the OP's discovery?

http://www.ebay.com/itm/For-Canon-LP-E6-EOS-60D-60Da-5D-Mark-III-Digital-LPE6-Battery-Pack-7-4V-2800mAh-/261220655933?pt=Batteries_Chargers&hash=item3cd1f6e33d (http://www.ebay.com/itm/For-Canon-LP-E6-EOS-60D-60Da-5D-Mark-III-Digital-LPE6-Battery-Pack-7-4V-2800mAh-/261220655933?pt=Batteries_Chargers&hash=item3cd1f6e33d)

Seems they have far more charge (2800 mAh) vs the original Canon LP-E6 (1800 mAh) so I would assume more punch => the latest the mentioned "phenomenon" would appear non?

On my side I'm curious to reproduce it. I haven't noticed on my 5DIII so will keep en eye next time
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: celltech on May 25, 2013, 09:33:25 PM
I had it happen before when using non-Canon batteries, even though the "reported" battery level was fine.  Can't say I have it happen with OEM batteries in either the bare camera or with a grip, but I usually am above 50% for a shoot.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: tpatana on May 25, 2013, 09:56:44 PM
When a battery goes flat it has less power, so it is reasonable to expect things to slow down. To maintain the same speed on less voltage you would need more current, that could give serious problems. Sounds like a safety feature to me. Bigger batteries would mean a heavier camera.

I don't buy that explanation. I mean, if the battery is flat, yes, but 50% is still plenty of power.

I don't say the phenomenon don't exist, because that I can believe. But it being direct affect from the battery level, I wouldn't think so. I've worked plenty on the cell phone designs, and the batteries we have usually work around same characteristics, ~1500-2000 mAh Li-ions. Cell phones are 3.7V, and 5D3 at 7.2V, but that's just because they use 2 cells in series.

Until about <25% of the capacity, the voltage level still stays considerably high, and there's no big voltage dip due to bigger current draws either. And cell phones draw >1A when they get power hungry. I don't know the 5D3 power draw when everything is active (taking photo, DIGIC crunching data as fast as possible, memory cards writing, mirror and shutter going, etc.) but I'd be surprised if the peaks are more than 0.2A (not including the LCD operation, that could take 0.1-0.2A alone). (if someone knows real current draws, please enlighten me).

Assuming that's true, which I don't know, the battery level could go down to <10% and still the voltage dips, caused by the current draw, would be minimal.

I haven't seen the schematics for Canon, but I'd be also really surprised if they don't have a regulator at the input. In my world that would be just poor design. If they do have regulator, it would eliminate the actual battery voltage completely at the camera end, and until battery is really down to <1%, the camera would receive proper voltage/current. Again, if someone knows the design or has the schematics, I'd be happy to learn the details.

I have the 5D3 with grip, and 2 Canon batteries. Occasionally I'm down to ~50% on long day, but I don't remember seeing this phenomenon, then again, I wasn't looking for it. Next time I'll try and see.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Dylan777 on May 25, 2013, 11:51:53 PM
I start loosing frame rate when battery @ quarter left.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: tpatana on May 26, 2013, 01:01:59 AM
Can someone confirm how it behaves with AAA-batteries on a grip?

This is strange indeed.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Skulker on May 26, 2013, 03:30:55 AM
When a battery goes flat it has less power, so it is reasonable to expect things to slow down. To maintain the same speed on less voltage you would need more current, that could give serious problems. Sounds like a safety feature to me. Bigger batteries would mean a heavier camera.

I don't buy that explanation. I mean, if the battery is flat, yes, but 50% is still plenty of power.

I don't say the phenomenon don't exist, because that I can believe. But it being direct affect from the battery level, I wouldn't think so. I've worked plenty on the cell phone designs, and the batteries we have usually work around same characteristics, ~1500-2000 mAh Li-ions. Cell phones are 3.7V, and 5D3 at 7.2V, but that's just because they use 2 cells in series.

Until about <25% of the capacity, the voltage level still stays considerably high, and there's no big voltage dip due to bigger current draws either. And cell phones draw >1A when they get power hungry. I don't know the 5D3 power draw when everything is active (taking photo, DIGIC crunching data as fast as possible, memory cards writing, mirror and shutter going, etc.) but I'd be surprised if the peaks are more than 0.2A (not including the LCD operation, that could take 0.1-0.2A alone). (if someone knows real current draws, please enlighten me).

Assuming that's true, which I don't know, the battery level could go down to <10% and still the voltage dips, caused by the current draw, would be minimal.

I haven't seen the schematics for Canon, but I'd be also really surprised if they don't have a regulator at the input. In my world that would be just poor design. If they do have regulator, it would eliminate the actual battery voltage completely at the camera end, and until battery is really down to <1%, the camera would receive proper voltage/current. Again, if someone knows the design or has the schematics, I'd be happy to learn the details.

I have the 5D3 with grip, and 2 Canon batteries. Occasionally I'm down to ~50% on long day, but I don't remember seeing this phenomenon, then again, I wasn't looking for it. Next time I'll try and see.

Isn't it funny how when someone is trying to make a point they only partly understand that they come out with a long post. ;D

Maybe you should explain to the Canon engineers why they were wrong to expect this, I'm sure they would benefit from your knowledge. (while your at it you might like to get this format programmers to add a "Sarcasm" emoticon for me)
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: tpatana on May 26, 2013, 04:22:00 AM
Isn't it funny how when someone is trying to make a point they only partly understand that they come out with a long post. ;D

Maybe you should explain to the Canon engineers why they were wrong to expect this, I'm sure they would benefit from your knowledge. (while your at it you might like to get this format programmers to add a "Sarcasm" emoticon for me)

I'm a physicist working on cell phone field, so it's my nature trying to dig the root cause for what's happening inside the devices. Battery being at 50% shouldn't be causing anything unless the design is really bad. So it makes me wonder why that could happen, and with the current draws of a camera it makes me wonder even more. But I don't know cameras good enough, so that's why I was hoping if someone else could fill in the information I don't know about.

And I'd be happy to work for Canon, that'd combine both my expertise and the hobby I love.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Skulker on May 26, 2013, 04:35:20 AM
Isn't it funny how when someone is trying to make a point they only partly understand that they come out with a long post. ;D

Maybe you should explain to the Canon engineers why they were wrong to expect this, I'm sure they would benefit from your knowledge. (while your at it you might like to get this format programmers to add a "Sarcasm" emoticon for me)

I'm a physicist working on cell phone field, so it's my nature trying to dig the root cause for what's happening inside the devices. Battery being at 50% shouldn't be causing anything unless the design is really bad. So it makes me wonder why that could happen, and with the current draws of a camera it makes me wonder even more. But I don't know cameras good enough, so that's why I was hoping if someone else could fill in the information I don't know about.

And I'd be happy to work for Canon, that'd combine both my expertise and the hobby I love.

Since you know so much more than them and no doubt would help prevent them producing "design that is really bad" they should be really appreciative that you would be prepared to give them the benefit for your extensive skill set.

The bit that really surprises me is that with this vast knowledge base why you "wonder" and then "wonder more" when you already know it all.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: tpatana on May 26, 2013, 05:40:19 AM
Isn't it funny how when someone is trying to make a point they only partly understand that they come out with a long post. ;D

Maybe you should explain to the Canon engineers why they were wrong to expect this, I'm sure they would benefit from your knowledge. (while your at it you might like to get this format programmers to add a "Sarcasm" emoticon for me)

I'm a physicist working on cell phone field, so it's my nature trying to dig the root cause for what's happening inside the devices. Battery being at 50% shouldn't be causing anything unless the design is really bad. So it makes me wonder why that could happen, and with the current draws of a camera it makes me wonder even more. But I don't know cameras good enough, so that's why I was hoping if someone else could fill in the information I don't know about.

And I'd be happy to work for Canon, that'd combine both my expertise and the hobby I love.

Since you know so much more than them and no doubt would help prevent them producing "design that is really bad" they should be really appreciative that you would be prepared to give them the benefit for your extensive skill set.

The bit that really surprises me is that with this vast knowledge base why you "wonder" and then "wonder more" when you already know it all.

Huh, what? You got upset because I said I didn't believe your guess?

I was just telling my knowledge about how batteries work on cell phones, and tried to compare how it should be in cameras if the design was done as I think it should be done, and was asking if someone knows more details. No reason to get upset, at no point I even said I know how it is, I was just making guesses and assumptions how it might be.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: RGF on May 26, 2013, 06:19:10 AM
Never noticed this, i'll check my 5D3 to see how noticeable it is.   I seldom do large bursts with the 5D3 except for HDR -which is why I may have not noticed it
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Timothy_Bruce on May 26, 2013, 06:26:35 AM
Does someone have a 5D3 with BG and can test if it slows down with alkalines or NI-MH accus inside the BG ?
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Brymills on May 26, 2013, 08:52:49 AM
I wonder how the new firmware affects this when using 3rd party batteries?  From reports I've read elsewhere the battery always reports 100% when using non Canon batteries regardless of the actual charge level.  Sounds like 3rd party batteries could be the way forward!  ;D
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Skulker on May 26, 2013, 02:47:51 PM

Huh, what? You got upset because I said I didn't believe your guess?

I was just telling my knowledge about how batteries work on cell phones, and tried to compare how it should be in cameras if the design was done as I think it should be done, and was asking if someone knows more details. No reason to get upset, at no point I even said I know how it is, I was just making guesses and assumptions how it might be.

I'm not upset, notice the smiley face? that's a bit of a clue that I was laughing.

I didn't make a guess, I said read the manual, were the behaviour is explained to be normal and expected.

You did say that the design was bad thus clearly implying that you knew better. Then you tried to justify what even you called "guesses and assumptions", you tried to say how knowledgeable you are. In my experience people who really know what they are talking about would want a lot more detail before condemning the design as "bad."
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Skulker on May 26, 2013, 02:48:56 PM
I wonder how the new firmware affects this when using 3rd party batteries?  From reports I've read elsewhere the battery always reports 100% when using non Canon batteries regardless of the actual charge level.  Sounds like 3rd party batteries could be the way forward!  ;D

Good point  8)
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: phoizen on May 28, 2013, 01:43:24 AM
Tested on my friends 5dMark3 yesterday with my 49% drained battery, and the FPS was normal and fast. Showed no drop even when we let the battery drain down to 15%. Going to run a shoot tomorrow with the AA battery pack and some eneloops.

Thanks for the info about letting the battery's drain! Totally did not know that.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Hobby Shooter on May 28, 2013, 02:36:39 AM
When a battery goes flat it has less power, so it is reasonable to expect things to slow down. To maintain the same speed on less voltage you would need more current, that could give serious problems. Sounds like a safety feature to me. Bigger batteries would mean a heavier camera.

I don't buy that explanation. I mean, if the battery is flat, yes, but 50% is still plenty of power.

I don't say the phenomenon don't exist, because that I can believe. But it being direct affect from the battery level, I wouldn't think so. I've worked plenty on the cell phone designs, and the batteries we have usually work around same characteristics, ~1500-2000 mAh Li-ions. Cell phones are 3.7V, and 5D3 at 7.2V, but that's just because they use 2 cells in series.

Until about <25% of the capacity, the voltage level still stays considerably high, and there's no big voltage dip due to bigger current draws either. And cell phones draw >1A when they get power hungry. I don't know the 5D3 power draw when everything is active (taking photo, DIGIC crunching data as fast as possible, memory cards writing, mirror and shutter going, etc.) but I'd be surprised if the peaks are more than 0.2A (not including the LCD operation, that could take 0.1-0.2A alone). (if someone knows real current draws, please enlighten me).

Assuming that's true, which I don't know, the battery level could go down to <10% and still the voltage dips, caused by the current draw, would be minimal.

I haven't seen the schematics for Canon, but I'd be also really surprised if they don't have a regulator at the input. In my world that would be just poor design. If they do have regulator, it would eliminate the actual battery voltage completely at the camera end, and until battery is really down to <1%, the camera would receive proper voltage/current. Again, if someone knows the design or has the schematics, I'd be happy to learn the details.

I have the 5D3 with grip, and 2 Canon batteries. Occasionally I'm down to ~50% on long day, but I don't remember seeing this phenomenon, then again, I wasn't looking for it. Next time I'll try and see.

Isn't it funny how when someone is trying to make a point they only partly understand that they come out with a long post. ;D

Maybe you should explain to the Canon engineers why they were wrong to expect this, I'm sure they would benefit from your knowledge. (while your at it you might like to get this format programmers to add a "Sarcasm" emoticon for me)
Some of us on this forum don't have English as a second language, I am sure it's fun for you to joke about it. For some of us we end up using more words to try to explain our point. Feel free to laugh at it though.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Skulker on May 28, 2013, 06:54:34 PM

Some of us on this forum don't have English as a second language, I am sure it's fun for you to joke about it. For some of us we end up using more words to try to explain our point. Feel free to laugh at it though.

The funny bit is not the poor language skills. You have made a nice attempt at diversion by implying that I am being nasty. For your information I am quiet dyslexic and would never mock someones attempts to communicate. I don't think anything I have said can be reasonably interpreted as mocking anyone's language skills.

FYI I find it strange and amusing that people get into such convoluted attempts to justify what amounts to guess work. The OP posed a question about reduced performance on reduced battery charge. While saying that he could not find any information about this issue. Yet it is in the manual that this will happen, then people start saying how bad it is and others try to say it should be better.  Why on earth would someone ask if there is any information available and then ignore the information available?. If someone claims to be an expert why would they ignore the information available and start making guesses and assumptions? That's what I find funny.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: tpatana on May 28, 2013, 07:04:13 PM

Some of us on this forum don't have English as a second language, I am sure it's fun for you to joke about it. For some of us we end up using more words to try to explain our point. Feel free to laugh at it though.

The funny bit is not the poor language skills. You have made a nice attempt at diversion by implying that I am being nasty. For your information I am quiet dyslexic and would never mock someones attempts to communicate. I don't think anything I have said can be reasonably interpreted as mocking anyone's language skills.

FYI I find it strange and amusing that people get into such convoluted attempts to justify what amounts to guess work. The OP posed a question about reduced performance on reduced battery charge. While saying that he could not find any information about this issue. Yet it is in the manual that this will happen, then people start saying how bad it is and others try to say it should be better.  Why on earth would someone ask if there is any information available and then ignore the information available?. If someone claims to be an expert why would they ignore the information available and start making guesses and assumptions? That's what I find funny.

If you cared to read my full post instead of choking on the first sentence where I said I didn't buy your explanation, maybe you would have understood the point I was trying to make.

I wasn't saying that the slowing doesn't happen, I was just trying to figure out what is happening inside the camera to cause it. And I was saying that in cell phone world not using a regulator would be bad (actually impossible) design, and I was wondering if camera could work without one.

So you though it'd be funny to make sarcastic remark that if I'm so clever I should go help Canon design better cameras. Real funny.

Actually English is my second language, Swedish third, German fourth and Japanese fifth. Also took some studies in other languages, (in descending order of skills) Korean, Spanish, Chinese and French.

So sometimes I need to write it bit longer so I don't get misunderstood. But still I can't help it if someone deliberately skips the points I make and hangs on to the few sentences they wanted to misunderstand.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: RustyTheGeek on May 28, 2013, 07:42:56 PM
I wonder how the new firmware affects this when using 3rd party batteries?  From reports I've read elsewhere the battery always reports 100% when using non Canon batteries regardless of the actual charge level.  Sounds like 3rd party batteries could be the way forward!  ;D

After I applied the latest April firmware update, the 5D3 now behaves just like the 6D.  (Canon Battery Haters - "No battery info for YOU!")  In other words, it chastises you when you power on the camera about the battery not being Genuine OEM and then doesn't report any info about the battery except that it's there.  So I guess we will have to wait a little while for all the 3rd Party battery makers to hack their battery firmwares to fool the newer cameras.  Ugh.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: luciolepri on May 28, 2013, 09:48:52 PM
Since the batteries are lithium, they should keep their voltage at 50% charge, so I don't get it too why the camera shouldn't work at its best in that condition. In fact, I have one original and three third party batteries and so far I never noticed any frame rate drop, nor I've ever heard my colleagues talking about this issue. The weird thing is that the "issue" is reported in the manual and so it is not an issue, but the normal behaviour of the camera. A behaviour that my camera doesn't respect... odd.
With my third party batteries, my MKIII works just fine, it shows a message the first time I turn it on, saying that the battery can't be recognized, but after that it's just like using the original batteries. Except that the original batteries last less.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: phoizen on May 28, 2013, 10:25:26 PM
Just wanted to report. Used one body today with standard eneloop AA batteries at a 50% overall charge. Shot for 5 hours and battery level dropped to 20%, however FPS did not drop in performance.

Not sure what the manual says about that one.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: Skulker on May 29, 2013, 02:31:12 AM

If you cared to read my full post instead of choking on the first sentence where I said I didn't buy your explanation, maybe you would have understood the point I was trying to make.

I wasn't saying that the slowing doesn't happen, I was just trying to figure out what is happening inside the camera to cause it. And I was saying that in cell phone world not using a regulator would be bad (actually impossible) design, and I was wondering if camera could work without one.

So you though it'd be funny to make sarcastic remark that if I'm so clever I should go help Canon design better cameras. Real funny.

Actually English is my second language, Swedish third, German fourth and Japanese fifth. Also took some studies in other languages, (in descending order of skills) Korean, Spanish, Chinese and French.

So sometimes I need to write it bit longer so I don't get misunderstood. But still I can't help it if someone deliberately skips the points I make and hangs on to the few sentences they wanted to misunderstand.

Thanks for another explanation and there was me with no idea that I was choking on your wise words. It's very good of you to help me. Also thanks for telling me that you never said what I never said that you said. I'm sure you were not trying to put words in my mouth.

Also thanks for explaining that English is your second language, that's pretty obvious. But I only mentioned it to point out it was irrelevant in reply to someone else, I never commented on your language skills. But it is so interesting to find you are a skilled multi linguist as well as a talented engineer.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: luciolepri on May 29, 2013, 08:54:48 AM
Not sure what the manual says about that one.

Don't know it myself, I just trust what others wrote....
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: dlleno on May 29, 2013, 10:07:53 AM
I think you guys are missing the point trying to explain this in terms of energy available from the battery.  The battery has enough available energy -- this is happening  because the firmware is forcing a lower fps.  I suppose this is an attempt to conserve energy I don't know, but I doubt this has been programmed because of insufficient power to move the mirror and activate the shutter. 

btw the manual can be found here:
  http://www.usa.canon.com/cusa/consumer/products/cameras/slr_cameras/eos_5d_mark_iii#BrochuresAndManuals (http://www.usa.canon.com/cusa/consumer/products/cameras/slr_cameras/eos_5d_mark_iii#BrochuresAndManuals)

top of page 114, at the end of the "selecting the drive mode" section:  "When the battery level is low, the continuous shooting speed may become slightly lower"
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: luciolepri on May 29, 2013, 10:58:40 AM
"When the battery level is low, the continuous shooting speed may become slightly lower"

This makes perfect sense, to me. That's why I don't think that an evident frame drop when the battery is only at 50% should be considered "normal". On the other hand, I'd consider "normal" if the frame rate slighlty drops when the battery is at 10%. Maybe it also depens on the lens used, if it has IS or not and things like that.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: dlleno on May 29, 2013, 11:05:36 AM
"When the battery level is low, the continuous shooting speed may become slightly lower"

This makes perfect sense, to me. That's why I don't think that an evident frame drop when the battery is only at 50% should be considered "normal". On the other hand, I'd consider "normal" if the frame rate slighlty drops when the battery is at 10%. Maybe it also depens on the lens used, if it has IS or not and things like that.

True -- my opinion here is that reason this is happening is because  the firmware decision-making could be complex,. considering other factors besides the exact level of charge reported by the battery which, by the way, can be different for after-market batteries.  Also, I think the manual is poorly written and may not be trusted to describe what is actually happening... :D
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: East Wind Photography on May 29, 2013, 11:47:39 AM
Postulating just for thoughts on how battery voltage can affect drive speed...and without knowing all of the facts this may or not be a possibility....

The battery is tied directly to the lens AF motor.  depending on the lens used may put more of a load on the battery and affect the AF speed of the lens.  If you have your camera firmware to 1st and 2nd shot focus priority, you could get yourself into a situation where slow AF can also slow your drive speed.

If you can reproduce the problem, please go into firmware and set 1st and 2nd shot priority to shutter priority and see if the speed picks up.  If so then you can say that AF speed may be the likely culprit. 


Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: dlleno on May 29, 2013, 12:03:38 PM
Postulating just for thoughts on how battery voltage can affect drive speed...and without knowing all of the facts this may or not be a possibility....

The battery is tied directly to the lens AF motor.  depending on the lens used may put more of a load on the battery and affect the AF speed of the lens.  If you have your camera firmware to 1st and 2nd shot focus priority, you could get yourself into a situation where slow AF can also slow your drive speed.

If you can reproduce the problem, please go into firmware and set 1st and 2nd shot priority to shutter priority and see if the speed picks up.  If so then you can say that AF speed may be the likely culprit.

or turn AF switch (on the lens) off.  The battery also powers IS, so turn that off as well.  Li batteries have very low internal resistance, so I really don't think this (by itself) is enough to explain the marked decrease in burst speed.  All these factors may be consistent with what I believe to be an unfortunately vague statement in the manual, i.e. if this was about battery behavior you might see 5.5fps instead of 6, which would occur at low battery levels, but it would not occur magically at 49%. 

I still think we have to think of this in terms of firmware behavior, not battery behavior.  The firmware's objective appears to be conservation of energy and prioritization of certain features like AF and IS ,which is may deem more important than burst speed. 

Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: East Wind Photography on May 29, 2013, 12:24:48 PM
I dont agree with it being a firmware issue as I have used my 5DIII with and without a grip and run the batteries down to where the icon blinks and all functions stop.  I've never had it slow down in drive mode except when the camera has focus priority set or if one of the CPU intensive functions are enabled such as HTP or high ISO noise reduction.

I am more inclined to think that the problem is tied either to bad or slow AF motor and/or settings within the firmware to prioritize focus before taking the shot...not a defect but how the camera is supposed to work in those situations.

However re-creating the problem and disabling all of the firmware priority and software functions can help do determine if it's firmware or not.


Postulating just for thoughts on how battery voltage can affect drive speed...and without knowing all of the facts this may or not be a possibility....

The battery is tied directly to the lens AF motor.  depending on the lens used may put more of a load on the battery and affect the AF speed of the lens.  If you have your camera firmware to 1st and 2nd shot focus priority, you could get yourself into a situation where slow AF can also slow your drive speed.

If you can reproduce the problem, please go into firmware and set 1st and 2nd shot priority to shutter priority and see if the speed picks up.  If so then you can say that AF speed may be the likely culprit.

or turn AF switch (on the lens) off.  The battery also powers IS, so turn that off as well.  Li batteries have very low internal resistance, so I really don't think this (by itself) is enough to explain the marked decrease in burst speed.  All these factors may be consistent with what I believe to be an unfortunately vague statement in the manual, i.e. if this was about battery behavior you might see 5.5fps instead of 6, which would occur at low battery levels, but it would not occur magically at 49%. 

I still think we have to think of this in terms of firmware behavior, not battery behavior.  The firmware's objective appears to be conservation of energy and prioritization of certain features like AF and IS ,which is may deem more important than burst speed.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: dlleno on May 29, 2013, 12:58:36 PM
hmm.... ok good point East Wind and also very different than what the OP mentions and different from what has been reported out on the canon forum.  assume from your description that you using 100% genuine Canon batts too. 

part of the problem here is that Canon is woefully unclear as to the precise expected  behavior. that said, something is causing some cameras to magically change burst behavior at 49% battery level.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: tpatana on May 29, 2013, 01:11:12 PM
Can someone who sees the slow down happening, confirm if they are using OEM or 3rd party batteries? Like me and couple others mentioned, the battery voltage level doesn't drop much until the battery is really close to 0%, the 50% mark shouldn't be any reasonable limit to start slowing down stuff. Also power(/current) delivery stays good until almost drained empty. That's why it would make sense it's FW decision to start slowing down, instead of the battery directly causing it. But if not everyone sees it, I wonder if there's other factors affecting the speed.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: East Wind Photography on May 29, 2013, 02:19:33 PM
Yes I always use genuine Canon batteries as I get more shots per charge using them as well as longer general life expectancy.  In the long run it's less expensive...but that's not relevant to this discussion. 

Most definitely though a non-canon battery could directly affect AF speed as the lenses pull their power for AF directly from the battery.  Any anomaly there would slow down drive speed IF 1st and/or 2nd shot priority is set to AF.

Now not to say that there is some other issue, I just brought it up as it's a common condition most people set and forget.

hmm.... ok good point East Wind and also very different than what the OP mentions and different from what has been reported out on the canon forum.  assume from your description that you using 100% genuine Canon batts too. 

part of the problem here is that Canon is woefully unclear as to the precise expected  behavior. that said, something is causing some cameras to magically change burst behavior at 49% battery level.
Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: phoizen on May 29, 2013, 03:46:36 PM
Not sure what the manual says about that one.

Don't know it myself, I just trust what others wrote....

Actually more often than not, the manual doesn't give you the best explanation. I think this issue has pretty much proven that so. But thanks for that helpful tidbit.

I only use Canon batteries and it's happening to me. My testing over the past few days has shown that the problem is inconsistent using different camera bodies, and AA batteries in the grip. Regardless of that, if the manual states an fps drop is normal with low battery charge...they consider 49% to be low? That's odd.

Title: Re: 5dm3 - FPS Drops when battery below 50%
Post by: dlleno on May 29, 2013, 04:01:15 PM
Not sure what the manual says about that one.

Don't know it myself, I just trust what others wrote....

Actually more often than not, the manual doesn't give you the best explanation. I think this issue has pretty much proven that so. But thanks for that helpful tidbit.

I only use Canon batteries and it's happening to me. My testing over the past few days has shown that the problem is inconsistent using different camera bodies, and AA batteries in the grip. Regardless of that, if the manual states an fps drop is normal with low battery charge...they consider 49% to be low? That's odd.

There appears to be at least two problem descriptions being articulated. First,  the magic 49% onset of burst speed degredation has to be firmware related.  unless someone can convince me that the battery's internal resistance suddenly jumps over a cliff at that point.  to the extent that firmware is involved, and makes decisions based on the charge level reported by the battery, then yes I  believe the use of third party batteries should be part of the discussion.  In any case, it appears that firmware is making priority decisions based on a number of factors not altogether known, causing behavior that is hard to understand. 

the other problem discription is a more physically explainable scenario where things slow down when the battery gets tired under heavy demand.   This fits more consistently with the manuals horribly vauge disclaimer that keeps Canon from holding themselves responsible to clearly state the expected behavior.