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09-26-2008, 07:40 AM   #16
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okay. I got the picture. Thanks so much for the information.

I guess it is not such a wise idea to try to use the burst mode for action shots, in view of all the limitations.

09-26-2008, 10:09 AM   #17
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QuoteOriginally posted by WMBP Quote
Well, I'm not sure what's going on with shutter speed. Obviously it can't be slower than 1/21th sec because the camera's taking 21 shots a second (or whatever it is). So if you needed a 1/20th sec exposure, well, I'm guessing that would get shortened automatically. But if a 1/500th sec shutter is adequate, I'm not sure whether the feature is giving you that (21 times a second) or not. I will say that, in my test shots, exposure seemed to be decent.l
Shutter speed doesn't enter into it because the shutter never moves. In burst shooting the shutter stays open for as long as you hold it open. The 21fps is applied electronically.
09-26-2008, 10:58 AM   #18
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QuoteOriginally posted by audiobomber Quote
Shutter speed doesn't enter into it because the shutter never moves. In burst shooting the shutter stays open for as long as you hold it open. The 21fps is applied electronically.
I was thinking of "shutter speed" in a sort of general way, not thinking of the mechanical shutter specifically. I would note that the images you capture on the K20D in burst mode DO have a shutter-speed value in the EXIF, and more than that, the value seems to matter. I just took a couple of quick tests. Setting the shutter to 1/300th and using burst shooting in full manual, I took some shots that were badly overexposed. Switching to P mode and letting the camera determine the exposure settings, the shutter speed was recorded as 1/400th sec and the images were decently exposed. So it SEEMS to me that the camera isn't just chopping the "open shutter time" into segments each of which is 1/21th sec long, but it may also be turning the sensor on and off within those segments, so long as the desired shutter speed is shorter (faster) than 1/21th sec.

But I really don't know....

Will
09-26-2008, 11:29 AM   #19
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Rfortson, golf swing was good use of 21 burst. Works well. Amazing how far something can move between shots at 21 fps.
Gooshin, nice videos. She is cute! Dogs are funny. Good use of music with K9s.

thanks
barondla

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09-26-2008, 01:24 PM   #20
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QuoteOriginally posted by audiobomber Quote
Shutter speed doesn't enter into it because the shutter never moves. In burst shooting the shutter stays open for as long as you hold it open. The 21fps is applied electronically.
I'm pretty sure "shutter speed" (used loosely) is relevant, though it's obviously an electronic equivalent, and not the mechanical shutter. Still it's clear from my pictures that the shutter speed is more than 21fps or the entire picture would be a blur. The 21fps is the sampling rate, and the shutter speed is the duration of each frame, so both values are needed, it seems to me. I need to go back and look if all the various settings are available in burst mode, and if they make a difference. I wish I'd done it at the golf course (that was my annual trip to the course) because a faster shutter speed would've stopped the club head, which is really what I wanted. I'd like to try 1/2000s or something like that.

As an aside, I've often wondered if P&S digital cameras even have a shutter, and if so, why? Since the sensor is just sampled, and you can set the sampling rate and duration, it seems to me that a shutter is redundant.
09-26-2008, 01:27 PM   #21
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not mine, but an IMO cool example of what you can do with the burst mode:

burst-sequence.gif (image)

from: chasing light...: Pentax K20d mini review
01-27-2009, 10:25 AM   #22
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First real HD clip (sort of)! I made-it! It's perfect, wo rolling shutter.
Must have xvid for example installed.
1. One burst or more but consecutive, wo gaps in numbering in a separate folder (or rename and recount with Total commander, Multirename tool, deleting initial numbering, or vdub show only first frame ).
2. Transform in BMP (works too direct from jpeg but with aliasing artefacts like in a computer game).
3. Open first bmp from serie from virtualdub.
4. Set fps at 15 or 20.
5. Set xvid compression at let's say 5.
6. Save as avi!
Result is a short HD clip in 1536/1024 resolution. At 268 frames joined result like 12secs and 3.8 MB of high quality movie. Must have enough light for at least 1/30 per frame, used iso 800, f4.5, 1/30, kit.
I put this first on my romanian forum, softpedia, with the same name silverflower in K20D topic.

Last edited by silverflower; 01-27-2009 at 11:44 AM.
01-27-2009, 08:51 PM   #23
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QuoteOriginally posted by silverflower Quote
First real HD clip (sort of)! I made-it! It's perfect, wo rolling shutter.
Must have xvid for example installed.
1. One burst or more but consecutive, wo gaps in numbering in a separate folder (or rename and recount with Total commander, Multirename tool, deleting initial numbering, or vdub show only first frame ).
2. Transform in BMP (works too direct from jpeg but with aliasing artefacts like in a computer game).
3. Open first bmp from serie from virtualdub.
4. Set fps at 15 or 20.
5. Set xvid compression at let's say 5.
6. Save as avi!
Result is a short HD clip in 1536/1024 resolution. At 268 frames joined result like 12secs and 3.8 MB of high quality movie. Must have enough light for at least 1/30 per frame, used iso 800, f4.5, 1/30, kit.
I put this first on my romanian forum, softpedia, with the same name silverflower in K20D topic.
Cool stuff.

Just a reminder that any of these settings which usually mean diving into one or more menus to engage are good candidates for a User setting. Then you just flick the dial to User and you are in the mode. I use mine for bracketing but you could easily do burst mode with this as well. I often wish there were more than one User setting.

Jack

01-27-2009, 09:53 PM   #24
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- It's nothing specific except enough shutter speed, that was the settings in that moment for usual pictures. I must repeat that on good light to check for rolling shutter with a fast enough panning; other than that 20-21 fps is not enough speed and on fast movement, the sensation is like an action computer game with not enough fast video card. Maybe I'll try to interpolate in vdub or other program for an 40 (42) fps, or put an motion filter. Testing underway!
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01-27-2009, 11:25 PM   #25
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I took two sequences of my kids jumping into a swimming pool & the resulting splash using 21fps burst mode. Compared to SD DV, the results are clearer (higher res & better lens). I did not find 21fps jerky.

I then took the sequence into Sony Vegas Pro (a video editor) and made a slide show sequence where each picture was held for 5 frames @ 25fps (PAL - i.e. for 200ms/shot). This is a 4.2x slowdown i.e. 21/25 * 5.

Dan.
01-28-2009, 12:45 AM   #26
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I apoligize for being too enthusiastic

I run some tests today and it have jelly - rolling shutter effect at fast moves. Previous first bursts was not intended to be made test movies and I moved slow the camera. One burst seem that have 117 frames (maybe is linked to content?). Good part is that we have control of image on back LCD. Horrible weather though...
silverflower

Last edited by silverflower; 01-28-2009 at 11:04 PM. Reason: not enough space
01-28-2009, 03:09 AM   #27
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Hey silverflower,

jZip says the .rar archives are corrupted.
01-28-2009, 03:51 AM   #28
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Hi,

I played with this feature when the K20D came out. I summarized my findings in the following threads:

- https://www.pentaxforums.com/forums/post-your-photos/21913-fireengine-k20d-movie-full-hd.html
- https://www.pentaxforums.com/forums/pentax-dslr-discussion/21941-k20d-burst-m...esolution.html

Contained therein are:

- Tipps and tricks, esp. about how to reduce the block artifacts and purple fringing found in the 21fps mode.
- MP4 sample movie: http://www.livis.de/download/pub/fireengine1080p24.mp4
- Sampe still image:
[IMGWIDELEFT]http://www.livis.de/download/pub/fireengine.jpg[/IMGWIDELEFT]


One thing to keep in mind is that the focus needs to be preset. This limits the set of possible subjects to static or wide angle ones. The fire engine subject is of the wide angle type.
01-28-2009, 04:28 AM   #29
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QuoteOriginally posted by ftpaddict Quote
Hey silverflower,

jZip says the .rar archives are corrupted.
- They are not corrupted. If your browser save them like zip, rename after that in RAR, and use a new version of winrar.

@falconeye
- I didn't know of your accomplishment. Like I said, first I had heavy aliasings too. By converting first in BMP jaggies dissapear completely, wo any filtering or resize.

Later edit:
I was wrong; the movie made from jpegs had applied some deinterlace filters in vdub that exacerbate aliasing artefacts. A small aliasing artefacts remains in any case, you are perfectly right to concentrate on them, but your method is a little complicated.

Last edited by silverflower; 01-28-2009 at 07:08 AM.
01-28-2009, 10:30 AM   #30
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QuoteOriginally posted by silverflower Quote
A small aliasing artefacts remains in any case, you are perfectly right to concentrate on them, but your method is a little complicated.
The small "aliasing" artifacts are there because the 21 fps images only have half the resolution Pentax marketing says. They are doubled in horizontal size. My method just undoes this doubling. I cannot think of any method simpler than this...

If Pentax already doesn't provide a firmware fix for this, at least, they could include an after-fix in PhotoLab (incl. one for the fringing as well). But they don't.
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