90D RAW only burst count

Started 2 months ago | Questions thread
RogerZoul Senior Member • Posts: 2,385
Re: 90D RAW only burst count

DavidArmenPhoto wrote:

RogerZoul wrote:

DavidArmenPhoto wrote:

Also keep in mind that although you may see a certain number Of shots available in the OVF, the camera begins writing to the SD card from it’s buffer almost immediately after you start shooting.
So as you shoot, ur camera is also transferring the photos from the buffer to the SD card simultaneously. So even thought it might show 15, you will get much more than that if you use a high speed uhs-ii card because the buffer will unload data to the card at a faster rate, giving it more room for new photos coming in.

Edit: For example, I just tried a quick test to get an example for you. I shot a relatively dark simple scene Raw at iso100 1/250 f4 and the camera was giving a burst count of 24 in the OVF. I am using a UHS-I Sandisk Extreme Pro with a tested average write speed of 88MB/s. I put the camera on continuous high and didn’t let go of the shutter until the camera slowed down at which time I let go immediately. I got 35 shots from that burst with the photos averaging about 27MB each. I believe I will get a higher rate with a UHS-II card with write speeds over 200MB/s even though the camera will still likely show a burst rate of 24 or 25.

Funny you mentioned this particular example. i was getting pretty much exactly as you describe here with an a Sandisc Extreme Pro UHS-I card. Then, I tried two different UHS-II cards (a Prograde and a Lexar) and now i only get around 24 shots before buffering stops completely. Something is amiss! I’m taking actual shots, not some number showing in the viewfinder. Talk about a downgrade! Not what I was expecting.

This is indeed an interesting development.
Are the before and after photos of the exact same scene? Raw size matters tremendously by ISO and scene detail, so the way I think of my raw buffer is by size not by number of shots. You might get a 20MB raw from one simple dark scene and get a 40MB raw file from a landscape scene all with the same exact settings including same ISO. So you must count the number of shots and also the average size of those shots to truly understand Or realize the speed difference.
Before having any ultimate conclusions, I would suggest you set up a semi studio still life environment with consistent lighting and put the camera on a tripod on manual everything including manual white balance and manual focus, and take the first burst with the UHS-I and then take the second burst with the UHS-II card. And compare results. I find this a little difficult to believe if all three of your SD Cards and your camera are functioning properly as it is physically impossible for a card with double the write speed to perform worse.

If you still get the same results consistently, you Most likely have a hardware issue Because I can’t think of anything else off the top of my head. In this case, the very first thing I would do is perform speed tests on all my SD cards using a computer. Blackmagic has a really good Disk Speed Tester for this and I am sure A quick search will reveal many more. Perform these tests and find the actual write speed of all three of your SD cards. Both the Lexar and Prograde should easily outperform the Sandisk by at least 50%. If you do not consistently get at least 140MB/s write speeds with the speed test software, your UHS-II SD cards are at fault. If you do get higher speeds from the UHS-II cards as you should, then your camera is the problem. For the latter case, contact Canon support with a detailed email/phone call about your issue.

ps. If you decide to perform the speed test on a computer, ensure that your card reader supports full UHS-II speeds otherwise the UHS-II SD cards will perform just as any UHS-I card, voiding your entire test.

pps. I would not contact Canon support before doing all the SD card testing because they will initially almost certainly blame the SD cards and ask you to get new ones.

Ok, thanks for this. The before and after we’re totally different scenes and not connected at all. However, I did test all three cards in an actual outdoor shooting situation (different days and conditions) and I noticed the same behavior.  Still, I will do as you suggest anyway because it seems reasonable and I was not really trying to be scientific in method. I do have a prograde card reader which is much faster than my UHS-I reader.  I will report back in this thread with my observations, but it make take several days.

 RogerZoul's gear list:RogerZoul's gear list
Canon EOS 7D Mark II Canon EOS 5DS R Canon EOS 5D Mark IV Canon EOS 90D Canon EF 500mm f/4.0L IS II USM +33 more
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