90D has no high-precision centre AF like 7D MK2?

Started 6 months ago | Discussions thread
Andy01 Senior Member • Posts: 2,990
Re: 90D has no high-precision centre AF like 7D MK2?

Andreas Berglund wrote:

Not sure I understand this. at 10 fps, if the buffer is 30 frames, it should do 3 seconds? or thereabouts?

I looked up the buffer on Canon USA its 25 RAW and 39 in C-RAW (https://www.usa.canon.com/internet/portal/us/home/products/details/cameras/eos-dslr-and-mirrorless-cameras/dslr/eos-90d-body )

That's about 4 seconds in my math....

BTW I shoot both Canon and Nikon, My D500 has 200 in RAW buffer, and that's what I'm comparing against not the 7DMKII, a very old design by now.


While the camera is shooting the first 3 seconds of images, it is simultaneously writing the data to the UHS-II SD card at a rate of about 5 fps, so in 3 seconds you have already written about 15 of the 30 shots to card, which frees up space to write another 15, and so on.

I do not think that the camera writes nothing to card until the buffer fills, and then starts writing, but I am happy to be corrected. In my experience, as soon as it has something to write to card, it does. Unless of course Canon has already taken this into account when they do there buffer test, but I don't think so.

That is why cameras can shoot longer bursts with faster cards.

I don't think any "prosumer" body is going to have a similar buffer size to a top-line pro grade body. TBH, I am not sure why given the current price of storage - realistically they could fit 8Gb of buffer memory (perhaps 200 RAW images) for a couple of dollars, but none of them seem to want to do that. 10-15 years ago, that 8Gb was worth something, but not currently.


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