Buffer Size difference with identical bodies?

Today I was shooting Motocross alongside a friend, I was using a 1DMKIV and a 1DMKIII, he was using a borrowed 1DMKIII. SInce Motocross is a fast paced sport the subject of the cameras buffer came up and I asked him if he knew how to tell how many shots are left in the buffer, to make a long story short we noticed that his MKIII ran up to 30, while both my cameras hovered at 24-26 max.

We then checked camera settings which were identical for both MKIIIs as well as swapping cards I could not get mine to go above 24 while the MKIV went to 26 max??

Firmware was the same, we just couldn't figure out what is going on.

does anyone have any idea or experienced this before?

Perhaps you were shooting at a higher ISO than him.

all camera settings were Identical we sat there and reviewed everything over the course of 5-10 minutes. we even swapped cards since we were both shooting Sandisk Extreme Pro, but I had a 32s and he 16s. So we swapped cards and no change, gotta pick CPS's brain soon.

hmm maybe one of the bodies has the long exposure noise reduction enabled

FuturamaJSP wrote in post #15936336
hmm maybe one of the bodies has the long exposure noise reduction enabled

We actually sat there and went thru every menu screen and every submenu all were identical and the 3 that weren't we switched with no difference, we were stumped..

Were you shooting the exact same scene with the exact same lens?

The reason I ask is that RAW (and JPEG) files are compressed... Images that contain more detail don't compress as well and have a larger file size. Images with less detail compress better and as such, are smaller. That's why if you look at the file sizes of your images, you'll see that they are all different.

This is also why the camera can't tell you exactly how many images you have left on the memory card. It can only provide an estimate.

I'm speculating that it's the compression that's causing the difference. The buffer holds a fixed number of megabytes. It doesn't care how many images there are. Once that megabyte pool is filled, the camera will stop recording.

What you'd need to do to confirm this is to add up the file sizes of all the images that were in the buffer for your camera and in the buffer of the other one. You might see that your 24-26 images contained just as many megabytes as the 30 images on your friend's camera.

Jim_T wrote in post #15936513
Were you shooting the exact same scene with the exact same lens?

The reason I ask is that RAW (and JPEG) files are compressed... Images that contain more detail don't compress as well and have a larger file size. Images with less detail compress better and as such, are smaller. That's why if you look at the file sizes of your images, you'll see that they are all different.

This is also why the camera can't tell you exactly how many images you have left on the memory card. It can only provide an estimate.

I'm speculating that it's the compression that's causing the difference. The buffer holds a fixed number of megabytes. It doesn't care how many images there are. Once that megabyte pool is filled, the camera will stop recording.

What you'd need to do to confirm this is to add up the file sizes of all the images that were in the buffer for your camera and in the buffer of the other one. You might see that your 24-26 images contained just as many megabytes as the 30 images on your friend's camera.

we were both using 70-200s we were looking at remaining images in buffer as displayed in the viewfinder, not remaining images on the cards.

When the buffer stops writing, it resets the counter to the maximum amount of images available to burst shoot, so both cameras were done shooting and processing files and still displayed different numbers.

I know that Canon specifies around 26 frames on the 1DMKIII but I was getting 24 he was getting 30??? He had a bigger buffer available than my 1DMKIV, i'm Starting to think it had something to do internally with his camera.

At lowest iso and darker imsges. is possible to shoot more buffer.
I tested my t2i shooting dark images at 100 iso with jpg.
It burst at the same speed never stop , unless I released the shutter. Haha.

If you both shot off a burst of out of focus, wide-open, even gray card shots - to get the detail out and compressibility high and the same between cameras, you would minimize or eliminate the real possibility of differences in subject matter affecting the prediction by the system.

AJSJones wrote in post #15936770
If you both shot off a burst of out of focus, wide-open, even gray card shots - to get the detail out and compressibility high and the same between cameras, you would minimize or eliminate the real possibility of differences in subject matter affecting the prediction by the system.

A good idea.

It could be that your images were sharp and well-focused, resulting in lots of detail that would be difficult to compress. Whereas your friend may have been shooting blurry images with little detail.

What about image res?
Raw, Sm, Med, Lge Jpeg

Guys I'm not speaking about photos taken, I'm talking about the size of a "clean" buffer before you start to take photos you look in the viewfinder and it shows the amount of shots available for burst shooting.

We looked at everything, I have spoken to another 1DMK3-4 owners and they all report buffer size around 26, It has to be something with his camera. I was hoping someone had seen this in past I wouldn't mind an extra 4-6 shots in the buffer.

MajesticMomentsPhoto wrote in post #15937465
Guys I'm not speaking about photos taken, I'm talking about the size of a "clean" buffer before you start to take photos you look in the viewfinder and it shows the amount of shots available for burst shooting.

Hmmmm, the only thing I've seen that changes that number is the ISO.

hollis_f wrote in post #15937472
Hmmmm, the only thing I've seen that changes that number is the ISO.

yes, we saw that. I was higher and my buffer was 24. So I lowered to match his but It only raised my buffer to 25. His was constantly at 30.

He was consistently @ 30.

How about this? https://photography-on-the.net/forum/showthre​ad.php?t=773505