What are your techniques in reducing chromatic aberration when imaging?

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Sir
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What are your techniques in reducing chromatic aberration when imaging?

#1 Post by Sir » Sat May 15, 2021 5:23 am

One thing I'm trying to improve is reducing chromatic aberration in my images, so I'd love to hear how everyone else deals with it.

- What steps do you take before taking a photo to reduce chromatic aberration?
- Are there any particular camera settings that help?
- How do you edit afterwards?

Thanks!

BramHuntingNematodes
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Re: What are your techniques in reducing chromatic aberration when imaging?

#2 Post by BramHuntingNematodes » Sat May 15, 2021 5:27 am

Use a good green filter then make the image black and white. An LED that narrowly emits light could presumably have even better effect.
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mrsonchus
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Re: What are your techniques in reducing chromatic aberration when imaging?

#3 Post by mrsonchus » Sat May 15, 2021 8:58 am

Yes, the green filter helps for certain, I use that technique quite a lot with high-dry objectives. Also keep the subject in the center of the field as much as possible, although you probably do this already quite naturally.
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Scarodactyl
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Re: What are your techniques in reducing chromatic aberration when imaging?

#4 Post by Scarodactyl » Sat May 15, 2021 6:09 pm

Generally chromatic aberrations are a setup issue rather than a technique issue. If you're seeing them really badly in your camera, especially if it's much worae than through the eyepieces, it may indicate the optical setup connecting the camera to the microscope has an issue, but we'd need more details to know.
Last edited by Scarodactyl on Sat May 15, 2021 10:51 pm, edited 1 time in total.

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Wes
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Re: What are your techniques in reducing chromatic aberration when imaging?

#5 Post by Wes » Sat May 15, 2021 6:27 pm

Sir wrote:
Sat May 15, 2021 5:23 am
- How do you edit afterwards?
Reduce color noise in photoshop works well.
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BramHuntingNematodes
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Re: What are your techniques in reducing chromatic aberration when imaging?

#6 Post by BramHuntingNematodes » Sat May 15, 2021 10:04 pm

Oh yeah, and I left this off because i thought it was too facile but is still a good method: use objectives with better color corrections.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Sir
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Re: What are your techniques in reducing chromatic aberration when imaging?

#7 Post by Sir » Sun May 16, 2021 4:12 pm

Wes wrote:
Sat May 15, 2021 6:27 pm

Reduce color noise in photoshop works well.
Just gave this a try, exactly the kinda tip I was looking for. Thanks a lot!

I'll also give some black and white images a shot with a green filter, as others have suggested.

Sir
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Re: What are your techniques in reducing chromatic aberration when imaging?

#8 Post by Sir » Mon May 31, 2021 11:50 am

BramHuntingNematodes wrote:
Sat May 15, 2021 5:27 am
Use a good green filter then make the image black and white. An LED that narrowly emits light could presumably have even better effect.
mrsonchus wrote:
Sat May 15, 2021 8:58 am
Yes, the green filter helps for certain, I use that technique quite a lot with high-dry objectives. Also keep the subject in the center of the field as much as possible, although you probably do this already quite naturally.
This was excellent advice! Posting my findings here in case it helps someone else in the future. Here's a comparison of a green filter vs no filter, converted to black and white. The green filter really seems to help with the contrast without the need of editing. Images are unedited other than the black and white filter. I did however have to slow down the shutter speed after adding the green filter, due to the reduced brightness.

(Note: The image is animated, it may take a moment to load)

Image

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mrsonchus
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Re: What are your techniques in reducing chromatic aberration when imaging?

#9 Post by mrsonchus » Mon May 31, 2021 2:30 pm

Great result - oh and I really like the animation - very useful here.
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DonSchaeffer
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Re: What are your techniques in reducing chromatic aberration when imaging?

#10 Post by DonSchaeffer » Mon May 31, 2021 6:30 pm

Interference patterns are part of what makes microscopes work. Chromatic abberation is part of the pattern of interference patterns. You may not be able to fully eliminate this kind of aberration in a compound microscope.

apochronaut
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Re: What are your techniques in reducing chromatic aberration when imaging?

#11 Post by apochronaut » Mon May 31, 2021 11:20 pm

What a peculiar thread.
You didn't indicate what you mean by image, sir but I am assuming you mean , captured image. Cameras tend to collect ca, like a mop gathers dust, so if you are using quite average achromats, then your tools of choice are digital.
You also didn't indicate whether you wanted a colour rendition of what you are looking at but since you seem happy with the results of green filtration, you might consider monochromatic light, too.
With white light the quality of the condenser has a small effect on ca, gaining momentum off axis, so attending to acquiring an achromat aplanat condenser is of some importance.

However, the most important tool available to the microscopist is patience. Patience to wait to acquire highly corrected optics, in this case. You will need little silicon wizardry after that. I see them regularly for sale at ridiculously low prices. 150.00 for a 4,000.00 objective is a common occurence. Entire sets of 160mm apochromats for 3 or 400 dollars. If you are terrified of buying a used microscope or used parts and or at the mercy of some altar of excellence as some of the "experts" on this forum are , then that is your folly and you will be destined to struggle with crappy equipment within your budget , prone to ca. It's pretty simple really. Look outside the box and you will most likely hit a home run.

EYE C U
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Re: What are your techniques in reducing chromatic aberration when imaging?

#12 Post by EYE C U » Tue Jun 01, 2021 2:08 am

lightroom

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