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JPEG for time-lapse with DSLR


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#1 Bernhard Zitz

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Posted 24 January 2008 - 05:11 PM

A question to people doing time-lapse or stop motion on DSLR.

I know that JPEG isn't the best choice for the job, but I get a usable amount of frames on a 1giga-card. Today I did time-lapse with the best JPEG-option 2secs between the shots, light situation didn't change between.

In the result I have some single frames that pop out a little darker from the rest. I know that JPEG will compress each frame individually, but two frames that are almost the same shouldn't be that different? Or is it the cameras interpretation of the raw data that varies?

Otherwise it's the mechanics of the camera or the iris of the lens.

Any advise or experience?

Is there a free tool to stitch RAW-frames together? What are Pro Stopmmotionguys using?

cheers, Bernhard
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#2 Simon Miya

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Posted 24 January 2008 - 05:13 PM

Are you shooting in full manual mode? Shooting in any auto or program modes will result in frames with differing exposure.

Edited by Simon Miya, 24 January 2008 - 05:16 PM.

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#3 Bernhard Zitz

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Posted 24 January 2008 - 05:25 PM

Are you shooting in full manual mode? Shooting in any auto or program modes will result in frames with differing exposure.

full manual
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#4 Daniel Sheehy

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Posted 24 January 2008 - 06:30 PM

A question to people doing time-lapse or stop motion on DSLR.

I know that JPEG isn't the best choice for the job, but I get a usable amount of frames on a 1giga-card. Today I did time-lapse with the best JPEG-option 2secs between the shots, light situation didn't change between.

In the result I have some single frames that pop out a little darker from the rest. I know that JPEG will compress each frame individually, but two frames that are almost the same shouldn't be that different? Or is it the cameras interpretation of the raw data that varies?

Otherwise it's the mechanics of the camera or the iris of the lens.

It's probably a result of minor variations when the lens stops down to the shooting aperture which result in variations in brightness and flicker in the finished sequence.
Try using a couple of different lenses. Another option is to use a manual lens.

The other option is your lighting source might have been flickering..?

These guys seem to have made an exhaustive investigation of the issue.
http://www.gbtimelap...pseFlicker.aspx
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#5 Bernhard Zitz

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Posted 25 January 2008 - 04:32 AM

The other option is your lighting source might have been flickering..?


The light source was fine, sun with plain blue sky, 2 secs between the shots.

I think it's the iris (F stop) like mentioned in the link. My problem looks like the split image. Thanks for the link.

I'll try a manual lens or the Autolens fully open or fully closed.

cheers, Bernhard
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#6 Phil Rhodes

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Posted 25 January 2008 - 07:17 AM

Hi,

I've shot a bit of timelapse on a Canon EOS-300D and didn't have any problems. I'm not sure whether the iris servos are actually in the camera or the lens, and even then, whether the precision of any mechanical linkage involved is a factor, but it never even occurred to me that there'd be a problem - and there wasn't. I was using the 60mm macro prime EF-S lens.

Phil
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#7 Simon Miya

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Posted 25 January 2008 - 05:54 PM

I think it's the iris (F stop) like mentioned in the link.


It might be illuminating to check the the EXIF tags of the offending frames, to see if they differ from the good frames.
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#8 Daniel Sheehy

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Posted 25 January 2008 - 09:58 PM

The light source was fine, sun with plain blue sky, 2 secs between the shots.

The guys on that site also noted that they particularly notice flicker in sequences with large expanses of blue sky...

Phil: If the issue is the lens iris servo, it would make sense then that some lenses perform better than others.
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#9 Bernhard Zitz

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Posted 27 January 2008 - 05:16 AM

I did some tests on blue sky in best JPEG:


Manual lens 1/400 f:16 iso:100 , zero flicker.

Manual lens 1/4000 f:4 iso:100 , minor flicker.

Autolens 1/400 f:22 iso:200, major flicker.

Autolens 1/4000 fully open (2.8) iso:100, minor flicker.



A manual lens at normal shutter speeds seems ok. At high shutter speeds (1/4000) the camera seems to be less accurate and you get flicker even with a manual lens or the autolens fully open.

Another thing is that the f stops don't correspond from one lens to another and not even on the same lens from one f stop to another, that's strange but has nothing to do with the flicker problem.
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