Comparison of AmScope's Plan & Non-Plan Objectives

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Sir
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Comparison of AmScope's Plan & Non-Plan Objectives

#1 Post by Sir » Fri Jul 10, 2020 8:55 am

EDIT: Please note that my initial post was NOT CORRECT - Please see my updated post below that shows a more realistic comparison between the objectives.

I own an AmScope T490B - Which comes with 4x, 10x, 40x, and 100x (oil) Non-Plan objectives (160mm). I figured I should upgrade to their Plan objectives, and wanted to do a comparison in case anyone else was also looking to buy the same objectives. I took pictures of a printed image with a coverglass (I don't have a reliable test slide yet) and found that there is hardly any difference between the objectives at lower magnifications. The 40x was the only objective that had some notable difference.

In my opinion, buying the 20x and 60x alone are worth it, but I probably wouldn't recommend upgrading to the Plan objectives with AmScope. You are welcome to look through the full album of images here and comparison below to see if you can notice much of a difference.

Please keep in mind that this was just a quick comparison and is just reflective of my own observations. I'm assuming my results would not be the same with some of the big 4 objectives, but I'm curious to hear other people's experiences.

Image
Last edited by Sir on Sat Jul 11, 2020 11:28 am, edited 1 time in total.

Hobbyst46
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#2 Post by Hobbyst46 » Fri Jul 10, 2020 11:13 am

Sir wrote:
Fri Jul 10, 2020 8:55 am
I own an AmScope T490B - Which comes with 4x, 10x, 40x, and 100x (oil) Non-Plan objectives (160mm). I figured I should upgrade to their Plan objectives, and wanted to do a comparison in case anyone else was also looking to buy the same objectives. I took pictures of a printed image with a coverglass (I don't have a reliable test slide yet) and found that there is hardly any difference between the objectives at lower magnifications. The 40x was the only objective that had some notable difference.
This comparison is very important and potentially of benefit to many.
I copied the picture to Irfanview and zoomed in. IMHO, there is no significant difference in planarity between the plan and non-plan, including the 4X, 10X and 40X.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

perrywespa
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#3 Post by perrywespa » Fri Jul 10, 2020 11:31 am

Thanks so much for doing this. I've been considering changing the objectives on my Seiler Westlab II to the Amscope Plan lenses and now I think I'll just replace my 100X oil, which I rarely use, with a 20X plan.
Perry
Seiler Westlab II, B&L Dynazoom, B&L Dynoptic, Vintage Leitz.

MicroBob
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#4 Post by MicroBob » Fri Jul 10, 2020 11:34 am

The term "PLAN" should ideally be accompanied by the size of the planar image. Over a field of 10mm many achromats are fairly plan, over e.g. 25mm not so.
Do you know how big the field is that your camera captures?
Did you cover the paper with water or oil and a cover slip?

I'm sure your comparison is valuable since many people are interested in buying Amscope microscopes.

Bob

Sir
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#5 Post by Sir » Fri Jul 10, 2020 11:43 am

MicroBob wrote:
Fri Jul 10, 2020 11:34 am
Do you know how big the field is that your camera captures?
Did you cover the paper with water or oil and a cover slip?
I'm unsure how to check the field size. I used an afocal setup with a 10x eyepiece and my Canon M50 with an 18-45mm lens. I wanted to leave the entirety of the eyepiece visible so that the field of view could be compared. It wasn't the strictest of experiments since the intention was just to check if there was any easily observable differences between the objectives, but I did ensure the camera and slide did not move between shots.

For all the images I had covered the paper in water and used a cover slip. Both to ensure it remained flat and also because I typically observe wet-mounted samples. Only the 100x had the additional of oil.

Hobbyst46
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#6 Post by Hobbyst46 » Fri Jul 10, 2020 12:06 pm

Sir wrote:
Fri Jul 10, 2020 11:43 am
MicroBob wrote:
Fri Jul 10, 2020 11:34 am
Do you know how big the field is that your camera captures?
Did you cover the paper with water or oil and a cover slip?
I'm unsure how to check the field size. I used an afocal setup with a 10x eyepiece and my Canon M50 with an 18-45mm lens. I wanted to leave the entirety of the eyepiece visible so that the field of view could be compared. It wasn't the strictest of experiments since the intention was just to check if there was any easily observable differences between the objectives, but I did ensure the camera and slide did not move between shots.
If the zoom was set to 40-45mm, I would guess that 60-70% (may be even more) of the actual field of view (by diameter, not area) was covered by the camera. Based on experience with my setup.
Last edited by Hobbyst46 on Fri Jul 10, 2020 12:31 pm, edited 1 time in total.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

Sir
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#7 Post by Sir » Fri Jul 10, 2020 12:14 pm

Hobbyst46 wrote:
Fri Jul 10, 2020 12:06 pm

If the zoom was set to 45mm, I would guess that 60-70% (may be even more) of the actual field of view (by diameter, not area) was covered by the camera. Based on experience with my setup.
Thanks! For these pictures it was set to 30mm if that helps

viktor j nilsson
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#8 Post by viktor j nilsson » Fri Jul 10, 2020 12:16 pm

I do agree that the soft edges looks like vignetting rather than the sharp edge of the field stop, suggesting that we are not seeing the full field of view.

When you sort it out, it will be very interesting to see this comparison.

May I also suggest that you crop just outside the field of view and post separate images for each magnification?

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ImperatorRex
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#9 Post by ImperatorRex » Fri Jul 10, 2020 2:51 pm

Best would be to use a kind of "mash" or specimen with lines for a comparison.
Example ist here:
viewtopic.php?f=24&t=5930&start=60#p71902

But this of coarse raises the question where to get such. But maybe somebody has another idea? Micrometer slides are sometimes used as a reference. Something else?

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#10 Post by Hobbyst46 » Fri Jul 10, 2020 3:44 pm

ImperatorRex wrote:
Fri Jul 10, 2020 2:51 pm
Best would be to use a kind of "mash" or specimen with lines for a comparison.
Example ist here:
viewtopic.php?f=24&t=5930&start=60#p71902

But this of coarse raises the question where to get such. But maybe somebody has another idea? Micrometer slides are sometimes used as a reference. Something else?
A stage micrometer would be best, but for the low magnifications, even a thin transparent ruler, or a graph paper/grid paper (either plain, as was used in the previous 200 years, or printed from the internet on translucent paper) might give an estimate. Because with 10X20mm eyepieces, the field of view is normally 2mm through the 10X and 5mm through the 4X.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#11 Post by PeteM » Fri Jul 10, 2020 4:31 pm

The field of view really is important. Hoping you can double check?

An achro should look the same for, say, about 15mm of the field as a Plan Achro. It would be out at 20mm (or up for better objectives) that we'd expect the Plan objective to keep more in focus. Using wide field eyepieces (maybe 10x/20FN with your scope?) it should be possible to double check if what the eye is seeing the same or wider than what the camera is seeing.

If they're actually the same, you'll have saved many new scope buyers some money. I suspect there are differences at full field edges??

One thing to keep in mind for purely visual purposes and especially when doing something like chasing protists around on a slide that the eye compensates for a lot and if a subject that is moving in and out of the plane of focus doesn't look much (if any) better (visually) in a plan objective. It's with photos that the plan objective should shine.

FWIW, there are now some pretty cheap micrometer slides available via Ebay from China. Even easier to know what field you're seeing through the eyepieces and through the camera.

Thanks for this test, Sir.

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#12 Post by MicroBob » Fri Jul 10, 2020 5:31 pm

Sir wrote:
Fri Jul 10, 2020 11:43 am
I'm unsure how to check the field size.
The 4:1 objective places an image of 4x linear size inside the tube. There it is picked up by the eyepiece and further enlarged. When you would take a ruler with 1mm scale you should be able to calculate the field number of the used eyepiece.

Bob

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#13 Post by Sir » Sat Jul 11, 2020 3:11 am

Thanks everyone! I did just get a calibration slide, I'll try to get more photos later tonight to figure this out.

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#14 Post by Sir » Sat Jul 11, 2020 11:27 am

I've taken another look and the suggestions that the entire field of view was not visible was absolutely correct. I took some images with my phone instead, which covered the entire field, and the differences between the objectives are very clear. The Plan objectives are certainly better and provide a much flatter view. This is observable at all magnifications, but is much more visible at higher magnifications as you can see below. Here are the full res images.

Thanks to everyone that pointed this out! I can only apologize for my initially misleading post. I've added a disclaimer at the top so that I don't steer anyone in the wrong direction with my initial test. Please feel free to suggest anything else I can add. I hope this makes the differences clearer. For me, the Plan AmScope objectives are absolutely worth the upgrade.

Image

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#15 Post by mrsonchus » Sat Jul 11, 2020 1:38 pm

Hmm, looks significant to me, especially for the 40x, where the central part of the image is improved within the area most concentrated-upon and indeed covered by a camera's FOV.
Almost seems to be a case of the higher the mag, the more noticeable the improvement.
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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#16 Post by MicroBob » Sat Jul 11, 2020 3:13 pm

Hi,
thank you for this thorough test! To me this looks like 19mm field of view. For flat objects the basic achromats are just about good for the central 10mm of the field of view. The 40:1 achromat also seems to have a lot of pincushion distorsion - is it possible that the autofocus of your phone focussed differently? What you could add are photos with the achromats focussed on the edge of the field. For objects that are not flat some curvature of field is less important, but there should be a point where the image at the edge actually is sharp.

Bob

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#17 Post by PeteM » Sat Jul 11, 2020 3:46 pm

Another than you. Very much appreciate your following through.

Perhaps another question. My guess is that you've been delighted to now have the 20x Plan, but maybe don't see the 60x as all that much better than the 40x - and not up to the 100x oil immersion? Have you had a chance do try those objectives and any qualitative thoughts?

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#18 Post by Sir » Tue Jul 14, 2020 3:32 am

Sorry for the late replies, it's been a busy week!
MicroBob wrote:
Sat Jul 11, 2020 3:13 pm
is it possible that the autofocus of your phone focussed differently? What you could add are photos with the achromats focussed on the edge of the field.

Bob
I don't believe it was the auto focus, but I did have to refocus the microscope when switching objectives. The eyepieces did reflect what I was seeing in the images. I had another look and I can indeed focus on the edge of the field so I will add some reference images later. Thank you for the suggestion.
PeteM wrote:
Sat Jul 11, 2020 3:46 pm

Perhaps another question. My guess is that you've been delighted to now have the 20x Plan, but maybe don't see the 60x as all that much better than the 40x - and not up to the 100x oil immersion? Have you had a chance do try those objectives and any qualitative thoughts?
I have to say I absolutely love the 20x and find myself using it all the time. The 60x is great if you want a dry alternative instead of messing around with oil for the 100x. From what I've read on here there might be better alternatives, but I personally find myself using the 60x quite often, especially when observing tiny diatoms where the 40x falls a little short. At $72 I really can't complain :D

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#19 Post by hans » Tue Jul 14, 2020 6:47 am

MicroBob wrote:
Sat Jul 11, 2020 3:13 pm
What you could add are photos with the achromats focussed on the edge of the field. For objects that are not flat some curvature of field is less important, but there should be a point where the image at the edge actually is sharp.
This reminds me of something I have been wondering about for a while. In typical achromatic vs. plan achromatic objective designs, is the planarity the only major difference, or does the correction for field curvature generally also result in better correction of other aberrations? In other words, with the non-plan and plan objectives both focused at the edge of the field as MicroBob is suggesting, what is the expected result?

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Re: Comparison of AmScope's Plan & Non-Plan Objectives

#20 Post by perrywespa » Sun Jul 26, 2020 8:58 pm

Thanks for your PM about the update!
Perry
Seiler Westlab II, B&L Dynazoom, B&L Dynoptic, Vintage Leitz.

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