MicrobeHunter.com Microscopy Forum

Hey folks! I put together a little video comparison between some different levels of objective correction so that people can get a good sense of what to expect between them as far as microbe hunting goes!

I know some of you are optical wizards and I assure you I'm aware of at least some of the many, many nuances left out of this video, but I had to keep the length somewhat reasonable and the content digestible! That said, if you have critiques, additional info, or ideas for future videos, please leave a comment below...

Appreciate your clear explanation and illustration of the differences. It's a question that's frequently asked. Thanks for taking the time to create and share this.

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+1 for Pete’s comments
This short video explains a lot, very effectively.

I was a little surprised that the intro had no ‘titles’ … Thirty seconds [even with good music] is a long time to wait … but the explanations were refreshingly clear when they came.

I would recommend it as ‘essential viewing’ for any newcomer; and as an enjoyable aide memoire for the experienced.

Nicely done !

MichaelG.

MichaelG. wrote: ↑

Tue Nov 30, 2021 9:36 am

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+1 for Pete’s comments
This short video explains a lot, very effectively.

I was a little surprised that the intro had no ‘titles’ … Thirty seconds [even with good music] is a long time to wait … but the explanations were refreshingly clear when they came.

I would recommend it as ‘essential viewing’ for any newcomer; and as an enjoyable aide memoire for the experienced.

Nicely done !

MichaelG.

PeteM wrote: ↑

Tue Nov 30, 2021 6:05 am

Appreciate your clear explanation and illustration of the differences. It's a question that's frequently asked. Thanks for taking the time to create and share this.

Appreciate the feedback, guys!

Michael, thanks for your insights! I agree the intros for my longer videos feel a little unfinished right now. I'm still trying to find my particular style and I'm totally new to video production so in the meantime I'm just starting my longer videos with music over clips from recent footage I've captured. It's hard enough work getting the actual meaty content done! I think I want to keep doing these sorts of intros in some way, but it would definitely be a good idea to remind the viewer that they are indeed watching the video they clicked on and not just some clipshow.

Thank you, this was an amazing video.

I totally agree with you that the defocused image looks much more pleasant on the apo objective. When you switched to the 10 x apo I was surprised by the increased resolution and the improved color rendition (I don't know is this concept applies), but I think the higher NA explains, at least partially, those changes, right?

Javier wrote: ↑

Wed Dec 01, 2021 12:03 am

Thank you, this was an amazing video.

I totally agree with you that the defocused image looks much more pleasant on the apo objective. When you switched to the 10 x apo I was surprised by the increased resolution and the improved color rendition (I don't know is this concept applies), but I think the higher NA explains, at least partially, those changes, right?

Thanks Javier!

Yes I would personally argue that increased numerical aperture is hands-down the most important and noticeable characteristic of a higher quality lens. I believe that making a lens apochromatic necessarily comes with an increase in NA, so you'll always see that. I think the main thing with colors that you notice globally when switching lenses is that, because this is a thick specimen, parts of the image are always slightly out of focus one way or the other. That means you'll always have some of that longitudinal (axial) chromatic aberration which causes the green/purple fringing. When you go to the apo lens, you don't get that any more so even if stuff's not WAY out of focus, it just looks more accurate globally. There's another youtube channel I'm a big fan of (redlettermedia) that has a phrase I love: "You might not have noticed that, but your brain did." I think that applies here as well. Even if it's hard to pin down the exact differences, the image just feels so much clearer and accurate.

By the way, I did make another super quick video showing the difference between numerical aperture differences at the same magnification:

Thanks for the info and the new video!

Javier wrote: ↑

Sun Dec 05, 2021 12:09 pm

Thanks for the info and the new video!

+1

Both of the videos are great. Like the way how you explain related to real samples everybody can refer to in practise.

What a great addition to the "microscopy community" you're becoming, Jason. That's a wonderfully concise and clear video.

Worth mentioning is that there is such a thing as the Superachromat! 4 colors in perfect alignment. Zeiss did a few of those for photography but I don't think anybody is making them anymore. There is also the possibility of creating what I guess would be a superb-superacrhomat and let's call the next an uber-superb-superachromat with five and six colors in perfect alignment. These would be sooooooo expensive with such a infinitesimal miniscule performance gain that there isn't even a point to try making one.

In microscopy they're typically called a super apochromat (nobody wants "achromat" on their high end optics), but it isn't consistent. Thorlabs sells "super apochromats", olympus has their plan super apos (now superceded by plan X apos), nikon has their "VC" line (violet corrected), etc. High end apos these days are probably not just corrected for three wavelengths to start with anyway. Once you get outside of the typical range of corrections you're usually going into specialty stuff which might be pitched differently for that reason.

don1357 wrote: ↑

Wed Dec 08, 2021 6:34 pm

Worth mentioning is that there is such a thing as the Superachromat! 4 colors in perfect alignment. Zeiss did a few of those for photography but I don't think anybody is making them anymore.

Yeah there's a footnote in Inoue's "Video Microscopy" (1986) in the aberrations section:

According to a recent Zeiss catalog, modern plan apochromats are corrected for four wavelengths in the dark blue, blue, green, and red for spherical aberration, and for more than four wavelengths for chromatic aberration, in addition to providing a flat field of view. Also modern fluorite objectives are corrected for blue, green, and red for spherical aberration, and for more than three wavelengths for chromatic aberration.

Not sure if he's talking specifically longitudinal chromatic aberration there or what. When you get into the weeds I think the only valid answer is you have to test and characterize each objective individually and compare it to others. Inoue himself was very fond of the plan-apo objectives since he would just use non-linear filters to pull additional contrast out of them.