Do we really need Sandisk Extereme Pro 95mbps read & 90mbps write speed?

Started Dec 26, 2013 | Discussions thread
Michel J Veteran Member • Posts: 4,009
Re: Do we really need Sandisk Extereme Pro 95mbps read & 90mbps write speed?
2

Ricky85 wrote:

Vikas Rana wrote:

nyoneway wrote:

Given that you have a A58, you will not be able to take advantage of the extra speed. Go with the cheaper one.

I've tested A58 burst rate with Tamron 17-50 here and I got 6fps in 1st second and 3fps onwards...

I've seen threads of A58 & A77 burst rate. After disabling distortion correction both the camera slows down after 1st second:

A58 can shoots 3 fps that means 8 x 3 = 24mbps

A77 can shoot 4 fps that means 10 x 4 = 40mbps

I don't get the same result as you with the A77.

I used a 32GB Sony SDHC UHS-1 Class 10, with 40MB/s write, and 94MB/s read,

I used the chronograph of an iPad3.

I shot xFine .JPEG

I make 12 shots the first second and 2 more shots until the buffer was full with a continuous burst flow.

The first shot was started up as the T = "0".

So it was 288 MB in 1,2 second, but hey, it's all the in-camera buffer who does that job (because it's much more faster than the write time of the memory card!).

If I'm not wrong, that tell to me we don't need the 90mbps write speed of the Sandisk Extereme Pro, to achieve the "12fps continuous shooting with autofocus" promised by Sony (but if we do only one burst session, because as you noticed after one second, the buffer is totally filled). We need it if we wants/needs less latency. But since we have to wait until the camera finish to write on the memory card to starting a new burst flow, we well know the existence of this latency and we don't care as much if it's a 90mbps or not, because it's not a continuous flow and we keep in mind that we have to wait already!

There after, if we expect waiting 3,2 sec instead 7,2, (depending on the performances we look for) it's a question of personnal appreciation and needs...

I tried doing sequences of 14 shots and waiting for a lag of about 4 seconds, but it wasn't sufficient to empty the buffer with the Sony (I don't have the SanDisk).

Then I tried sequences of 14 shots and a lag of about 10 seconds, that works but I can repeat only 3 times x 14 shots. More than that, it begins to be eratic. So, maybe I need to try sequences of 12 shots only and waiting about 10 seconds. But it's difficult to quantify precisely the burst flow VS lag time, because that makes the shooting session very fast. Does a 90 MB/s could help here? I really don't know, but I think yes. Unfortunately I'm unable to test that right now.

In the other hand, if we makes short sequences of 3 or 4 shots between sessions and wait a tad 'till the next new burst of 3 or 4 shots (as usually we must do so out of a test session), that works perfectly well, and we feel no latency between burst session with the Sony card.

Yes Vikas, truly speaking we do not need that Sandisk Extereme pro anymore. I cannot expect A77 to write images at more than 45mbps.

It's not when you shot what is important. The question is about the along of the latency between two burst sessions, I guess.

The final conclusion is Sony 32GB will give you the same performance of Sandisk 90mbps on any Sony DSLR/SLT

Right now I have no idea, but I think it's not. Need to confirm this point.

Regards,

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Michel J
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