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Fast low-resolution burst/continuous mode

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Offline cyril42e

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  • SD1000/Ixus70 1.02a
    • CR-TEKnologies
Re: Fast low-resolution burst/continuous mode
« Reply #10 on: 07 / July / 2008, 17:59:06 »
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Uhm, for what is worth... on my A720, if I set the "digital teleconverter" on, and keep a resolution of 1600x1200 or lower, burst mode becomes faster: some 1.5 fps rather than the usual 1.3 or so.

Yes, the digital teleconverter speeds continuous mode up from 1.5fps to 2fps on sd1000 (digital 1.9x, 1600x1200).

But no noticeable difference between 7MP super fine (~3MB files) and 2MP normal (~300KB files), always 1.5fps. That's strange because writing 3MB on the SD card at 20MB/s takes ~0.15s, which is the difference between 1.5fps and 2fps (0.65s to 0.5s), withnotstanding jpeg processing which should be faster too. So why isn't there any change in speed ?

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Offline dzsemx

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  • [SX40HS][A650][A630]
Re: Fast low-resolution burst/continuous mode
« Reply #11 on: 07 / July / 2008, 18:20:29 »
just a notice:
on a650 iso3200 scene mode uses preview / live view data for taking picture
i can't shoot normal raw in this mode, i can't see too much valid data in this mode
seee image
made with raw develop using normal auto mode
and  i didn't notice speedup when using teleconverter
« Last Edit: 07 / July / 2008, 18:25:01 by dzsemx »

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Offline cyril42e

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  • SD1000/Ixus70 1.02a
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Re: Fast low-resolution burst/continuous mode
« Reply #12 on: 07 / July / 2008, 18:27:47 »
on a650 iso3200 scene mode uses preview / live view data for taking picture
How can you get 1600x1200 resolution with live view?

I think the viewport resolution is lower than VGA, and video mode is VGA at 30fps...

and  i didn't notice speedup when using teleconverter
did you reduce resolution to 1600x1200 too?

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Offline fudgey

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Re: Fast low-resolution burst/continuous mode
« Reply #13 on: 08 / July / 2008, 13:21:19 »
Oh, nice find. Indeed, on a570is too the digital teleconverter speeds things up. When Tv or NR from high ISO doesn't slow shooting down, I get 2.0 fps at 1,9x digizoom (equals to 1600 pix width source image as seen from property #92) and 1600x1200 output jpg.

640x480 seems work at the same or almost the same speed even though the camera has to scale down the image(?). Scaling up to 2048x1536 slows it down significantly.

Digital tele 1,5x gives 2048 pixels wide source image, shooting to 2048x1536 from it gives a burst rate of 1.9 fps.
Shooting to 1600x1200 is slower, about 1.8 fps. This must be due to scaling... scaling the smaller 1600x1200 to 640x480 is so much faster that I couldn't measure it on this quick test.

Without digital tele I got 1.6 fps at full 3072x2304 resolution and 1,55 fps at 1600x1200.

I shot superfine quality to a Sandisk Ultra II 1G card, no RAW obviously, in M mode at Tv=1/1000s and ISO80.

(I measured the time it took for 50 shots for these figures, not very accurately)


 

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