Pentax *istD can't exploit fast cards such as Lexar WA cards

Archived from groups: rec.photo.digital (More info?)

I raised this subject in a thread "Pentax *istD & Lexar WA technology -
any experience?". (No responses!) I wondered why my Pentax was only
writing to a Lexar 80x WA card at 2MB per second, although the card
supports 12MB per second even without Write Acceleration technology,
and should be up to 23% faster with WA technology.

I have had a long on-line dialogue with Lexar support, and a
substantial telephone conversation with a Lexar technician. The
conclusion appears to be that the Pentax *istD is incapable of writing
to ANY card much better than 2MB per second, whatever the speed of the
card or the acceleration technology supposedly used.

This suggests that if you want faster write speed than 2MB per second,
don't buy a Pentax *istD. And if you have a Pentax *istD, you may see
no performance advantage from a card that is significantly faster than
2MB per second. The bottleneck appears to be in the Pentax, not in the
card. And that applies to Sandisk Ultra II cards too.

In the Lexar labs, their bus analyser shows that the Pentax does indeed
use the WA standard. But it takes 5.7 seconds to transfer 14MB, even
without the extra overheads that the Pentax needs to store a Raw file.
Lexar's tests of the Pentax writing to a Sandisk Ultra II card was 6
seconds, very little difference. The 7 seconds I was seeing for a 13MB
file included overheads that their bus analyser wasn't looking at. All
these figures are probably reasonably consistent.

Lexar promote the fact that the Pentax *istD supports WA technology.
But the slowest Lexar card with WA technology is far faster than the
Pentax can handle even WITHOUT WA technology! It may be that WA
technology in the Pentax *istD is totally irrelevant, used for mutual
Pentax/Lexar promotion, not for photographer benefit.

--
Barry Pearson
www.barry.pearson.name/photography

Archived from groups: rec.photo.digital (More info?)

> Barry Pearson writes ...
>
>I wondered why my Pentax was only writing to a Lexar 80x WA
>card at 2MB per second, although the card supports 12MB per
>second

This sounds about right, the Canon 10D only does about 1.4 MB/sec with
that card, the Canon 20D about 5.7 MB/sec (from Galbraith's tests).

Archived from groups: rec.photo.digital (More info?)

It is like CD-Rs. The speed is determined by the divice that writes, until
you each the maximum writable speed of the media. I buy CD-Rs that are
capable of being written by my fastestburner, which is somewhere around 40x,
but use the same CDs in my older 24x and 8x writers too.

--
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"Barry Pearson" <news@childsupportanalysis.co.uk> wrote in message
news:1113414978.279387.177930@z14g2000cwz.googlegroups.com...
> I raised this subject in a thread "Pentax *istD & Lexar WA technology -
> any experience?". (No responses!) I wondered why my Pentax was only
> writing to a Lexar 80x WA card at 2MB per second, although the card
> supports 12MB per second even without Write Acceleration technology,
> and should be up to 23% faster with WA technology.
>
> I have had a long on-line dialogue with Lexar support, and a
> substantial telephone conversation with a Lexar technician. The
> conclusion appears to be that the Pentax *istD is incapable of writing
> to ANY card much better than 2MB per second, whatever the speed of the
> card or the acceleration technology supposedly used.
>
> This suggests that if you want faster write speed than 2MB per second,
> don't buy a Pentax *istD. And if you have a Pentax *istD, you may see
> no performance advantage from a card that is significantly faster than
> 2MB per second. The bottleneck appears to be in the Pentax, not in the
> card. And that applies to Sandisk Ultra II cards too.
>
> In the Lexar labs, their bus analyser shows that the Pentax does indeed
> use the WA standard. But it takes 5.7 seconds to transfer 14MB, even
> without the extra overheads that the Pentax needs to store a Raw file.
> Lexar's tests of the Pentax writing to a Sandisk Ultra II card was 6
> seconds, very little difference. The 7 seconds I was seeing for a 13MB
> file included overheads that their bus analyser wasn't looking at. All
> these figures are probably reasonably consistent.
>
> Lexar promote the fact that the Pentax *istD supports WA technology.
> But the slowest Lexar card with WA technology is far faster than the
> Pentax can handle even WITHOUT WA technology! It may be that WA
> technology in the Pentax *istD is totally irrelevant, used for mutual
> Pentax/Lexar promotion, not for photographer benefit.
>
> --
> Barry Pearson
> www.barry.pearson.name/photography
>

Archived from groups: rec.photo.digital (More info?)

Chris Brown wrote:
> In article <1113427188.541334.81240@l41g2000cwc.googlegroups.com>,
> Bill Hilton <bhilton665@aol.com> wrote:
> >> Barry Pearson writes ...
> >>
> >>I wondered why my Pentax was only writing to a Lexar 80x WA
> >>card at 2MB per second, although the card supports 12MB per
> >>second
> >
> >This sounds about right, the Canon 10D only does about 1.4 MB/sec
with
> >that card, the Canon 20D about 5.7 MB/sec (from Galbraith's tests).
>
> This seems to be a really big issue for some people. One can't help
but
> think that if they wanted to shoot continuous video, they'd be better
off
> with a video camera. That way, they get to record their continuous
stream of
> pictures, and don't have to put up with the mirror flapping about
between
> frames.

I was talking about shooting Raw photographs, not video. The Pentax
*istD appears to be limited to taking about 13 Raw photographs within
the first 60 seconds of switching it on, even with the fastest cards.
Or one Raw photograph every 7 seconds if sustained over minutes. That
is quite slow when shooting people or animals in motion.

--
Barry Pearson
www.barry.pearson.name/photogr­aphy