Is there a better way to show motion?

[specious_reasons]

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?

[Craig Gerard]

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

[rjlittlefield]

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

[specious_reasons]

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.

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.

[johnsankey]

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.

[specious_reasons]

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)

[specious_reasons]

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.

[specious_reasons]

Zerene Stacker - only the frames where the Vorticella didn't move.


I adjusted the color curve. Not too bad.