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specious_reasons
Joined: 24 Feb 2009
Posts: 99
Location: Woodridge, IL
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 Posted: Sun Apr 08, 2012 7:19 am Post subject: Is there a better way to show motion? |
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I took a long exposure of this vorticella in darkfield to try to show the swirling eddies it creates. I set the ISO to the lowest I could, and set a long exposure time.
I didn't find a very good sweet spot between long enough to catch the motion and overexposing the background. Obviously stationary debris created huge light bubbles even on this relatively short exposure.
I'm wondering if a better choice would have been multiple shorter exposures either focus stacked or combined in some other way.
Any thoughts? |
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Craig Gerard
Site Admin
Joined: 01 May 2010
Posts: 2627
Location: Australia
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| Posted: Sun Apr 08, 2012 7:20 pm Post subject: |
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One suggestion when attempting to capture motion without blowing highlights, is to use a neutral density filter; but it may no be applicable in this micro situation.
Craig
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To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!" |
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rjlittlefield
Site Admin
Joined: 01 Aug 2006
Posts: 12696
Location: Richland, Washington State, USA
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| Posted: Sun Apr 08, 2012 10:12 pm Post subject: Re: Is there a better way to show motion? |
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| specious_reasons wrote: | | I'm wondering if a better choice would have been multiple shorter exposures either focus stacked or combined in some other way. |
Yes, this does sound like a better approach. Zerene Stacker PMax might do a good job, or Photoshop with blend mode set to Lighten. I've seen both those approaches used for creating star trails and combining lightning bolts without blowing out constantly illuminated areas. If your camera will record video, you might consider extracting frames from that to combine. Those would be lower quality images, but would give you the option of getting frames that were quite close together in time.
--Rik |
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specious_reasons
Joined: 24 Feb 2009
Posts: 99
Location: Woodridge, IL
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| Posted: Mon Apr 09, 2012 1:44 pm Post subject: Re: Is there a better way to show motion? |
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| rjlittlefield wrote: | | specious_reasons wrote: | | I'm wondering if a better choice would have been multiple shorter exposures either focus stacked or combined in some other way. |
Yes, this does sound like a better approach. Zerene Stacker PMax might do a good job, or Photoshop with blend mode set to Lighten. I've seen both those approaches used for creating star trails and combining lightning bolts without blowing out constantly illuminated areas. If your camera will record video, you might consider extracting frames from that to combine. Those would be lower quality images, but would give you the option of getting frames that were quite close together in time.
--Rik |
I don't have the full Photoshop, but I'll find the equivalent in GIMP or Elements. I wouldn't have thought of Lighten, though, I would have tried to use transparency. Thanks.
| Craig Gerard wrote: |
One suggestion when attempting to capture motion without blowing highlights, is to use a neutral density filter; but it may no be applicable in this micro situation. |
Yes, unfortunately, the debris was small and dimly lit. Reducing the amount of light probably would have avoided overexposure, but it might have not captured what I was trying for. Well, it can't hurt to try.  My light source is adjustable, I think I can get away with just turning down the brightness. |
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johnsankey
Joined: 02 Mar 2012
Posts: 18
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| Posted: Mon Apr 09, 2012 3:39 pm Post subject: try the startrails program |
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| There's a free program called startrails that is designed to do the job. I've used it to get two hour trails even in a city environment where the maximum time exposure was 15s to avoid background light wiping out the stars. |
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specious_reasons
Joined: 24 Feb 2009
Posts: 99
Location: Woodridge, IL
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| Posted: Mon Apr 09, 2012 4:36 pm Post subject: |
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This might also be another opportunity to write another GIMP script.
(or just use one from the GIMP registry: http://registry.gimp.org/node/25638) |
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specious_reasons
Joined: 24 Feb 2009
Posts: 99
Location: Woodridge, IL
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| Posted: Wed Apr 11, 2012 2:44 pm Post subject: |
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This was a new try. This is using "Lighten only" and masking out parts of the frames where the vorticella had moved. Unfortunately, I had a hard time finding any vorticella and didn't have a very shot here:
I'll post the results of a PMAX focus stack when I get one. |
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specious_reasons
Joined: 24 Feb 2009
Posts: 99
Location: Woodridge, IL
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| Posted: Wed Apr 11, 2012 3:05 pm Post subject: |
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Zerene Stacker - only the frames where the Vorticella didn't move.
I adjusted the color curve. Not too bad. |
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