Wikipedia:Featured picture candidates/Oxalis triangularis photonasty

Oxalis triangularis photonasty (video) edit

Voting period is over. Please don't add any new votes. Voting period ends on 21 Jun 2010 at 14:47:34 (UTC)

Original - Oxalis triangularis (also known as the love plant or purple shamrock) is a classic example of a plant which responds with movement to an external stimulus. The leaves open and close in response to varying light levels with the result that they are open during during the day and close at night. This is true movement (i.e. not growth) and is non-directional with respect to the stimulus, making it an example of nastic movement towards light, a process known as photonasty. This video was produced with one image captured every 30 seconds for about one and a half hours, played back at 25 frames per second; ~750x actual speed. The exposure time was progressively increased through the video so the drop in ambient light levels are not seen.
Alternative - Modified version to include a representation of the lowering light levels.
Reason
This is a high quality video example of an unusual natural phenomenon; plant movement (more specifically a nastic movement in response to light called photonasty).
Articles in which this image appears
nastic movement

Oxalis triangularis

FP category for this image
Wikipedia:Featured pictures/Plants/Others
Creator
Richard Wheeler (Zephyris)
  • Support as nominator --- Zephyris Talk 14:47, 12 June 2010 (UTC)[reply]
  • Support Original This I can support, educational and 720p. — raeky (talk | edits) 16:32, 12 June 2010 (UTC)[reply]
  • Comment: I've tweaking the caption a little bit, I hope you don't mind. J Milburn (talk) 18:52, 12 June 2010 (UTC)[reply]
Fair enough, it reads much better. - Zephyris Talk 19:20, 12 June 2010 (UTC)[reply]
  • Comment: In some ways, it's a shame that the light levels don't change in the video- we kind of miss the point of the movement. J Milburn (talk) 18:54, 12 June 2010 (UTC)[reply]
It is a nightmare to try and capture the images allowing a decrease in light levels, there is such a huge intensity change that you will crash very quickly from overexposed to underexposed. The maths to correct image brightness according to f/exposure/speed is fairly simple though and corrected brightness could be back calculated if there is interest... - Zephyris Talk 19:20, 12 June 2010 (UTC)[reply]
I'd like to see that, even if it has to be tweaked slightly to make things still visible, it would add value as an alternative, if nothing else.
I have made and uploaded a version with darkening. Note this darkening is "fake", it is approximately 1/4 the actual lowering in light levels over this time period. - Zephyris Talk 23:52, 16 June 2010 (UTC)[reply]

Promoted File:Oxalis Triangularis Photonasty Timelapse.ogv --Makeemlighter (talk) 01:10, 22 June 2010 (UTC)[reply]