Cyanobacteria (video < 1 min)

[gekko]

Cyanobacteria (Peranema, etc., can also be seen at the beginning of the video). Source: bird's bath; objectives: 10x, 20x, 40x; illumination: DIC; camera: Olympus E-P1. I may have posted this on the old forum, but I could not verify that (apologies if you are seeing for the 2nd time). [75RR: here I do not see the banding I sometimes get, but perhaps you could comment if you do see it-- many thanks].


(Please click on vimeo to watch it full size in HD)
 

[75RR]

Nice video. No banding that I could see! Love the DIC clarity and detail.

[Crater Eddie]

Very nice video, thanks for posting it. No banding visible from here.
I was looking at some of this Saturday, it always surprises me that these fellows are motile.
CE

[mrsonchus]

No banding for me - plays perfectly with the (built-in) Chrome flash player. Fantastic video. Stunning clarity.

[rnabholz]

Hi Gekko,

May I suggest YouTube as a host for your videos?

Nine times out of ten I access this board from Android based devices, a phone and tablet, and these videos don't play on them, even using Flash friendly browsers like Dolphin.

YouTube is free and as the world largest video site, compatable with every device out there. For what it is worth.

I will check it out on the old windows laptop later in any event. ;^)

Rod

[gekko]

75RR, CE, mrsonchus, and Rod,
Thank you all very much for your kind words, and for the assurance of "no banding". CE, yes I find it amazing not only that they move, but the "elegance" with which they move.
Rod, I apologize for the video being in a format that is not easy for you to view (that may be the same reason that Manfred could not view it). Thank for your encouragement to use Youtube. I have resisted doing so because I do not wish to subscribe to Google (or Yahoo for that matter), which is why I use vimeo.

Banding:
Here are links to a couple of videos that do show banding:
https://vimeo.com/119194479 (first few seconds)
https://vimeo.com/117649566 (about 10 seconds into the video, I believe I have posted this video to the forum earlier)
 

[75RR]

Saw your banding - as you say - first few seconds in the first video and at around 10sec into the second.

Unusual banding, it does not flow as I would expect it to.

This is a test I made on a torch I was hoping to adapt to my microscope as a light source.
This small torch not only has a zoom function (wide to narrow beam) that diffuses the intensity of the light, a sort of mechanical dimmer, but also has several power outputs: 100% - 75% - 50% and 25%.

Video starts at 100 next is 75, then 50 and then 25 and back to 100.



Watched both of your videos till the end - hope that is not illegal. ;)

[rnabholz]

Banding:
Here are links to a couple of videos that do show banding:
https://vimeo.com/119194479 (first few seconds)
https://vimeo.com/117649566 (about 10 seconds into the video, I believe I have posted this video to the forum earlier)
 

Well now, if I click on the links above I am able to see the videos. Perhaps the issue is with the inline viewer link?

Both are excellent by the way. Very cool.

Rod

[gekko]

Watched both of your videos till the end - hope that is not illegal.

You'll be hearing from my attorney .
Your bars move because the flicker frequency is not an exact multiple of the camera's frame rate (or vice versa) and it appears to vary with the power setting of the flashlight. In my videos, the flicker frequency is 120 Hz, and the camera frame rate is 30 fps or very close to that. If it had been 29 or 31 fps, then I would expect the bars to move upwards or downwards. I think one can use the analogy of a strobe light aimed at a rotating fan; as you vary the frequency of the strobe, the blades may appear to slow down, stop (when the strobe frequency is an exact multiple of the blade 'rotation'), then reverse direction. If you use a battery-operated flashllght that uses a tungsten bulb instead of an LED, then, as you would expect, you will not see bars in your video.

[gekko]

Well now, if I click on the links above I am able to see the videos. Perhaps the issue is with the inline viewer link?
Both are excellent by the way. Very cool.
Rod

I don't understand what may be happening. I'm glad you could see the videos in the link, and many thanks for your kind comment. Were you also able to see the original cyanobacteria video? If not, I would find that rather odd, although I don't really understand the computer aspect of this.
Thanks again!

[vasselle]

Bonjour Gekko
Très belle vidéo
Cordialement seb