Partial blue filter = 3d image?

[Shivs]

I accidentally noticed today that putting my blue filter partially on adds a depth to the image, is this a known technique? What causes this phenomenon?

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[Shivs]

just a correction on this, it appears the ring around the filter holder is partially obscuring the light path. Still not sure what this is caused by.

[MicroBob]

You created some kind of oblique lighting.

[dtsh]

I am guessing it's much the same effect as I've noticed where reducing the light intensity or closing the condenser iris sharpens contrast.

[Shivs]

I made a quick video to show this better. its pretty neat

http://office.shivs.org:5080/3.mp4

[Sir]

Shivs, what you're describing is called "oblique Illumination." Since your microscope contains a filter holder, you can create oblique filters fairly easily to consistently reproduce this effect at varying magnifications.

Here's some more information on how oblique illumination works:
https://www.microscopyu.com/techniques/ ... lumination

and a link on how to create these filters
https://www.microbehunter.com/oblique-illumination/

[Shivs]

Shivs, what you're describing is called "oblique Illumination." Since your microscope contains a filter holder, you can create oblique filters fairly easily to consistently reproduce this effect at varying magnifications.

Here's some more information on how oblique illumination works:
https://www.microscopyu.com/techniques/ ... lumination

and a link on how to create these filters
https://www.microbehunter.com/oblique-illumination/

Thanks! I made a quick filter and filmed some. Most of my samples died so all I have are these colpoda right now..
http://office.shivs.org:5080/oblique.mp4

[Greg Howald]

Check the height of the condenser, the opening of the diaphragm and make sure the filter holder is completely closed. This should help to eliminate accidental oblique lighting. Then make some filters and do it on purpose. Have fun
Greg