1Dx and 1Dx2 owners- help

umphotography wrote in post #18852656
This appears to be what happened. I duplicated it last night when trying to figure out how it happened. I must have pushed that button by accident while i was turning the back wheel for adjusting the aperture when I was shooting.

Calling Canon Monday. according to what I have read, there may be a way to disable this

If you bump it, then it changes the CF card and not the C-fast. Thankfully, the C-fast had all the raws

OMG what a potential nightmare. been using 1Dx and 1Dx2 bodies since they came out...first time I have heard about this or experienced this

Why anyone would shoot a wedding with a non dual card camera without both cards recording full raw at the same time is mind boggling to me. I just got very lucky. The Small Jpeg files were 1.7-2.3 MB......too small.

I'm happy to see that this turned out to be your eventual issue. Would be scary if the body was doing this on it's own. I shoot a lot of pro sports and need the speed so sadly I can't have RAW's saved to both cards because it slows down the shooting speed. I learned about this too when I was shooting but lucky for me I was out testing a new lens at the time it happened. Would have been a disaster if it happened during a paid gig.....

snowblower wrote in post #18853826
I'm happy to see that this turned out to be your eventual issue. Would be scary if the body was doing this on it's own. I shoot a lot of pro sports and need the speed so sadly I can't have RAW's saved to both cards because it slows down the shooting speed. I learned about this too when I was shooting but lucky for me I was out testing a new lens at the time it happened. Would have been a disaster if it happened during a paid gig.....

Are you sure this is the case? I used to shoot RAW to one card and JPEG to the other but this drastically reduces the buffer depth because the camera is having to process the two streams differently. If you shoot RAW to both cards you get the full buffer depth and I have never noticed any reduction in frame rate. There are other settings (such as focus priority) that can reduce the frame rate, but (in my experience anyway) shooting RAW to both cards does not.

One word of caution though - I recently had a CFAST card failure and lost all the 50+ shots in the buffer. I checked with Canon and apparently this is just the way it is. If the camera can't write to a card it just hangs. It would be better if it just disabled the faulty card and continued with the working one.

[Edit] I just had a quick look at the manual. The frame rate is unaffected by the image size setting. The only thing the image size affects is the maximum burst (i.e. the buffer depth). For an unlimited maximum burst rate, shoot JPEG to both cards. RAW to both cards gives a 73 shot buffer (using a high speed CF card). Raw to one and large JPEG to the other reduces this to a 54 shot buffer.

Scott_online wrote in post #18853920
Are you sure this is the case? I used to shoot RAW to one card and JPEG to the other but this drastically reduces the buffer depth because the camera is having to process the two streams differently. If you shoot RAW to both cards you get the full buffer depth and I have never noticed any reduction in frame rate. There are other settings (such as focus priority) that can reduce the frame rate, but (in my experience anyway) shooting RAW to both cards does not.

One word of caution though - I recently had a CFAST card failure and lost all the 50+ shots in the buffer. I checked with Canon and apparently this is just the way it is. If the camera can't write to a card it just hangs. It would be better if it just disabled the faulty card and continued with the working one.

[Edit] I just had a quick look at the manual. The frame rate is unaffected by the image size setting. The only thing the image size affects is the maximum burst (i.e. the buffer depth). For an unlimited maximum burst rate, shoot JPEG to both cards. RAW to both cards gives a 73 shot buffer (using a high speed CF card). Raw to one and large JPEG to the other reduces this to a 54 shot buffer.

I get what you are saying but my claim is based on a “rate-in vs rate-out” issue and hitting the “buffer wall”. Canon doesn’t specify the buffer size of the Mark II but I was informed by someone at Canon Professional Services that the buffer size & write speed is the same for both card #1 (UDMA 7 Compact Flash) and card #2 (CFast 2.0). The problem lies with the cards themselves because the fastest Compact Flash card is approximately 160MB/sec. and the CFast card is up around 525MB/sec. Basically, the CFast card can handle 3.3 times the amount of data per second over the Compact Flash card. I perform a lot of continuous shooting (8-9 seconds) at shutter speeds between 1/1600 – 1/2500 and what I found when shooting to both cards the buffer will fill up and begin reducing the FPS so the camera can catch up on the file transfer. When I shoot to the CFast card independently I never hear it slow down. When I was shooting to both I found somewhere around 5-7 seconds the FPS would begin to slow. My only guess is the transfer speed of the camera is somewhat near the speed of the CFast card but much faster than the Compact Flash card. This is why I only use the one card (CFast) when I shoot fast action because the Compact Flash card can’t handle the transfer rate. BTW, The cards I was using when I experienced this issue was a Lexar 3500x 525MB/sec CFast card and a Sandisk Extreme PRO 160MB/sec UDMA Compact Flash card.

snowblower wrote in post #18854700
I get what you are saying but my claim is based on a “rate-in vs rate-out” issue and hitting the “buffer wall”. Canon doesn’t specify the buffer size of the Mark II but I was informed by someone at Canon Professional Services that the buffer size & write speed is the same for both card #1 (UDMA 7 Compact Flash) and card #2 (CFast 2.0). The problem lies with the cards themselves because the fastest Compact Flash card is approximately 160MB/sec. and the CFast card is up around 525MB/sec. Basically, the CFast card can handle 3.3 times the amount of data per second over the Compact Flash card. I perform a lot of continuous shooting (8-9 seconds) at shutter speeds between 1/1600 – 1/2500 and what I found when shooting to both cards the buffer will fill up and begin reducing the FPS so the camera can catch up on the file transfer. When I shoot to the CFast card independently I never hear it slow down. When I was shooting to both I found somewhere around 5-7 seconds the FPS would begin to slow. My only guess is the transfer speed of the camera is somewhat near the speed of the CFast card but much faster than the Compact Flash card. This is why I only use the one card (CFast) when I shoot fast action because the Compact Flash card can’t handle the transfer rate. BTW, The cards I was using when I experienced this issue was a Lexar 3500x 525MB/sec CFast card and a Sandisk Extreme PRO 160MB/sec UDMA Compact Flash card.

That makes sense. If you are shooting only to the CFast card, the maximum burst is 170 frames.

Do make sure you run the 'Sanitizer' app from Sandisk on your Sandisk CFast cards regularly. This performs a low-level format of the card. I've had 2 Sandisk CFasts lock up on me now. Sanitizer has recovered the cards but I lost the shots in the buffer at the time.

I got a detailed response when I asked about buffer for the 1DXII

https://photography-on-the.net …showthread.php?​p=18649334

graham121 wrote in post #18649822
In theory, yes RAW to CFast, JPG to CF does slow down the camera.... in reality --- not that you would notice.

Just ran a quick test @14fps indoors in artificial light.

RAW + Large JPG to CFast ...63 shots before hitting the buffer, ie 4.5 secs.

RAW to Cfast, Large Jpeg to ..... 132 shots before hitting the buffer, ie 9.5 secs.

RAW only to CF ..... 78 shots before hitting the buffer., ie 5.5 secs

RAW only to CFast .... gave up waiting for the buffer to fill.

So unless you are into really looooooonng bursts, for all intents and purposes there is no really noticeable slow down.

When the buffer did fill with the RAW + Large JPG to CFast, it really cleared quickly and the camera could carry on at around 8 fps, hitting the buffer when writing to the CF did slow things down more noticeably as the buffer cleared more slowly.

So in summary, the 1DX2 is a burst beast with the Cfast, and not too shabby at all with CF.

YMMV with different Cards, camera settings and environment.

Hope that helps.

With regards:
RAW to Cfast, Large Jpeg to ..... 132 shots before hitting the buffer, ie 9.5 secs
That should be RAW to CFast, JPEG to CF


I think it's obvious that small differences in actual cards used could make significant differences in performance experienced.

umphotography wrote in post #18853171
The way its programmed from the factory, you have to spin the back wheel and press button at same time to make the change occur.

No, that's not it. You actually first press the button, then rotate one of the two dials to do something. After that, you either press the button again to cancel it, or press some other button, or wait for it to time out.

Which probably makes it even more likely that you can change something by mistake. Not that I'm any professional (I do this for fun), but I've never pressed that button and changed anything by mistake. I've done some other stupid mistakes, but not that.

Wow, glad that I came across this thread. I shoot weddings and use both the X and X II and have never had this happen. But I'm glad that I now know what to watch out for. Thanks OP for sharing this with us.

When I read your first sentences I had a feeling it was something like you described.

It's similar to the reason my EOS R custom menu doesn't have the format card in the custom menu where it would easily be enacted by a couple of unintentional fumbles or touches.