Citation de: MouLaG Ôfr le 29 Octobre 2010 à 13:21:17


 et augmentera de 8 à 20 le nombre d'images RAW que le K-5 est capable de prendre en continu

I discussed the raw buffer properties with Gordon at DPR.

Here is my latest assessment after taking the firmware announcement into account:

Re: K-5 RAM size - big enough for a 20 frame buffer (RAW): Pentax SLR Talk Forum: Digital Photography Review

And this is what I said:

    yes,

    the new Pentax announcement indicates that Gordon's assumption was correct (full raw frames in the buffer) and that now they move to a scheme like I hinted at (compressed files in the buffer). 20 compressed RAWs are 400 MB, so, the minimum memory needed would be 512 MB much like Gordon assumed.

    If the memory was 1024 MB in the first place, it is unlikely that the initial write buffer was crippled to 8 frames (256MB or 1/4 of memory) only.
    If it is 512MB, then the available memory for processing (256MB initially) would now be lower (112MB) and I don't think they have been that radical in redoing their algorithms.

    Therefore, I think that the memory is 512MB and the write buffer (256MB) is now used for compressed RAWs yielding 13 RAWs, not 20. If 20 isn't an error in translation (like 20% better), then they may additionally offer a 12Bit option which is also known as level compression, a rather common option elsewhere. 20 requires to store 17 (3 can be written to SD) or 15MB per RAW, corresponding to 13.7 MB for a K-7 RAW taking the #pixels into account. That's a familiar size indeed

    So, that's my new guess indeed:

    1. 512MB overall memory, 256MB reserved as write buffer (WB) to SD

    2. FW 1.0: Partioned into 32MB 16Bit memory frames -> 8 RAWs in WB


    3. FW x.x (Nov):

        * Compressed 14Bit raw files -> 15 RAWs (13 in WB, 2 written)
        * Compressed 12Bit raw files -> 20 RAWs (17 in WB, 3 written)

    So, if the announcement is accurate, it implies (if my reasoning isn't flawed) that they add a 12Bit option too. It would be strange if they would only enable it in burst mode, so yeah, we may see a general level compression option (aka 12 Bit).
    The good thing is Pentax is listening
    The bad part is that they didn't use state-of-the-art coding in the first place

Yes, the buffer size would shrink at higher ISO. But maybe only roughly proportionally to the size increase of 12Bit raw files.

Citation de: Axxl le 29 Octobre 2010 à 20:47:28

on avait pas sdxc, on avai pas le controleur sd qui le permet

Citation de: Pixel le 29 Octobre 2010 à 21:13:21

à ce prix pour les cartes, t'as intérêt à les surveiller  

http://img263.imageshack.us/img263/92/sshot271.jpg

Contents of updating :

1. Increases the number of continuous shot at RAW and RAW+ mode.
*Setting condition: RAW(PEF)/ISO100, Increases the number of continuous shot from maximum approx. 8 frames to approx. 20 frames.

2. Improved stability for general performance.

Release date : Middle of November

Citation de: MouLaG Ôfr le 02 Novembre 2010 à 12:57:47

Mais aussi, cette amélioration ne serait que à ISO 100 et pas autrement, à vérifier ce qu'ils vont nous sortir  ...