Filters in front of lamp housing

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F4
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Joined: Sun Feb 12, 2017 5:18 pm

Filters in front of lamp housing

Post by F4 »

Image

This was shot using an Optiphot microscope with the original lamphousing, not the LED version. I noticed that the background is kind of an off-white yellow-ish color, and it does not convert to white very well even when resetting the white balance point in post-production.

Does anyone know if this can be fixed using the NCB10 filter, seen on this page? https://lavinia.as.arizona.edu/~mtuell/ ... lters.html

When it comes to filters being placed right in front of the lamphousing - there are none that came with my microscope. Are there any filters actually worth getting that would make a significant difference to the appearance of what you are lighting up? An ND filter seems like it would be pointless, as you can always use more light (not less), but what about some sort of polarizing filter, interference, diffusion, or heat absorbent filter, as listed on that page? What is a "GIF" filter and an "L" filter? Are any of these useful for placing in front of the lamphouse? Does anyone have any example pictures?

The microscope did come with the slide-in metal plate with the two small circular holes, although I haven't got a chance to look in the manual yet to look up what they are - I know one of them is a polarizing filter.

Pau
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Post by Pau »

You can use a light blue conversion filter, there are tons of models (the NCB seems one of them), usually new microscopes with incandescent/halogen lamps come with that kind of filter.
Be aware that if you change the illumination intensity of the lamp the color temperature also changes, here ND filters can be useful to set the lamp at high power (higher color temp) without burning your eyes

With digital cameras the easier and most accurate solution is to do a custom white balance without subject in the field or to shoot raw and adjust the WB in post processing (my personal option). Even so, a light blue filter is always desirable also for visual work.

GIF Green Interference Filter is a high quality green filter useful to take B&W pictures because it eliminates blue and red light and so it improves the sharpness with objectives not well color corrected like achromats. Usually it comes with phase contrast equipment.
No idea about what a L filter could be.
Pau

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