Zitat:
Zitat von WB-Joe
Hm, scheinbar geht der RIV da die Rechenleistung aus.
Bin gespannt wie sich da die A1 benimmt.
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Im Fred Miranda gabs da schon ne Tabelle/Berechnung dazu...
https://www.fredmiranda.com/forum/topic/1685546/
Zitat:
The A9 it is rated at 240 images at 20fps. If you hold down the shutter until the buffer fills you find there are ~205 frames in the buffer (hard to get exactly but a bit over 200). That means about 35 have already been written to the card by the time the buffer filled. The file size is ~23-24MB/frame, so 35*23.5MB were written in 240/20 seconds, which is ~69MB/sec. That is about half the rated speed of the camera writing onto the card. That means while the buffer is filling, speed writing to the card is cut in half.
I tried to test this on my A7S3 but could not get the buffer to fill. I was writing 25MB files to the card at 10 fps and the buffer never seemed to have any files when I released the button. The writing speed to the card was about >250MB/sec which is near the rated speed of the card (300MB/sec). That would seem to indicate that the new dual processor electronics can match the writing speed of the UHS-II cards. Can it match the rated write speed of the cf express A? We will have to wait to see.
If we assume the A1 writes at full card speed while the buffer is filling and after it is filled, and we assume the 155 frames is for the CF Express, and the file size is 44MB, then:
- it takes 155/30 = 5.17 sec to fill the buffer
- as the buffer is filling, files are being written to the card at a rate of 700/44 = 15.9 files/sec
- that means a net of 30-15.9 = 14.1 files/sec are accumulating in the buffer
- during that time 14.1*5.17 = 73 files have accumulated in the buffer
- the buffer is 44*73 = 3200 MB
- it will take and additional 3200/700 = 4.6 sec to clear the buffer.
That is the same as you calculated.
For the UHS-II:
- as the buffer is filling, files are being written to the card at a rate of 300/44 = 6.8 files/sec
- that means a net of 30-6.8 = 23.2 files/sec are accumulating in the buffer
- it will take 3200/(23.2*44) = 3.13 sec to fill the buffer
- during the 3.13 seconds, 30*3.13 = 93 frames will be captured before the buffer fills.
- it will take an additional 3200/300 = 10.7 sec to clear the buffer.
Additional conclusion:
- at 16.9 frames/sec the buffer will never fill with a CF Express type A card.
- at 6.8 frames/sec the buffer will never fill with a UHS-II card.
You can easily make adjustments to the assumptions to make alternative calculations. We will need to await more information to make better calculations.
BTW, I make a lot of errors, so check everything.
Dave
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Die neue Generation (ab A7sIII) scheint 200-250MB/s zu schreiben.
