AmScope 18mp MU1803 calibration I need help bad.

[FossilRaist]

This is my first camera set up so I have a ton to learn. And I'm either an idiot or I've gotten into my own head and caused a confusion that needs repaired.

I am used to taking photos with my phone through an ocular of other scopes so that the image I take a photo of is the true magnification. For instance on my Celestron 4040 I had 10X oculars and either a 2X or 4X objective. On the 4X with the oculars my photos were at 40X magnification correct? (see this new camera thing makes me question everything I used to think I knew)

So while calibrating my new setup I figured in the 20X oculars and when I thought I was almost done I realized my mistake. The oculars do not come into play with the camera, so now I have to start over.

My AmScope Microscope has the capabilities of 3.5X to 180X depending on my lens setup obviously (well until the camera I thought it was easy).

The camera has a .5 reduction attachment. Which should act what I understand a .5 Barlow does and halves my magnification. Seems simple enough, but it's so not simple, or I trashed my brain on this and can't figure out what I'm missing.

To explain AmScopes calibration the program requires I have the Zoom at 100% and the Live resolution at it's highest which is 4912 X 3684. I'm hooked up to an old laptop for these purposes. The settings like that do not allow the full image to fit the window of the screen. The real kicker is on this page https://amscope.com/pages/cameras-and-magnification AmScope claims to get the monitor magnification

So if a camera's image-sensor has a 1/2" diagonal, and the on-screen image has a diagonal of 23", then the monitor-magnification (mm) would be 46X. This only works if the entire image produced by the camera is seen on the monitor. If only a portion of the image is viewable, then the on-screen image will have to be reduced in size until it is fully visible

.
So I reduced the size to fit the window like that describes. I get 11" which gets doubled (I'm not sure why) to 22". This is their equation.

(mo) x (mm) x (ma) = m 20 x 46 x 0.5 = 460

So with my objective at (mo)4.5 X (mm) 22 X .5 = 495 magnification.

I have tried and tried to get this. I am fried and kind of worn out trying to wrap my head around this whole camera thing. All I want to do is have it calibrated so that I can have a scale in my photos for fossil related stuff. If you can help please give me the simplest explanation or go into great detail

I would really appreciate the help.

[BramHuntingNematodes]

They're just saying that if you got a.bigger.monitor you got a.bigger picture. They multiply by 2 in the example because the sensor diagonal is 1/2". Listen if you want to have a scale for your photos you want to use a.micrometer slide and figure it out directly.

[FossilRaist]

They're just saying that if you got a.bigger.monitor you got a.bigger picture. They multiply by 2 in the example because the sensor diagonal is 1/2". Listen if you want to have a scale for your photos you want to use a.micrometer slide and figure it out directly.

I have one. That's what I mean by I'm trying to calibrate it. Have I just way over thought it?

Say with oculars I'm 20X and objective 1X I'm at 20X magnification correct?
So with the camera I'm .5X and 1X I'm at ?X magnification?

I'm trying to figure out what magnification to label my scale at each objective and Barlow I would add. It seems like it should be so easy (and I thought it was) but now after a week of it my brain is shot.

[FossilRaist]

Ok wait. I think viewing on the screen is part of my problem in getting this. If the camera is .5X and I'm set at 1X with my objective that means I'm at .5X magnification. Right?

Now say I add a .5X Barlow. Would that halve it again to .25 magnification or work with the camera and give me a 1X magnification? Still at 1X objective of course.

[BramHuntingNematodes]

You know what the size of the micrometer scale is and you can measure the scale on the monitor with a ruler. Divide the values, right?

[FossilRaist]

No it's not that. I was right in that I've really gotten into my own head over this. I don't want to know the magnification on the screen in the sense of how big it is on my screen. I'm looking to label my scale size of say 1mm at different magnifications. I think I've needed to write this down and get confirmation because in my head I've over thought it and it doesn't make sense.

The camera is .5 and reduces the objective by half. So that means that my 1X objective instead of being 10X with oculars is .5 instead, at least that's how I understand it.

So my next thought is does a .5 Barlow reduce it by half again and bring it to .25 or counteract the camera and bring it to 1X?

The lack of ocular is what's making the equation difficult for me. I'm so used to 10X or 20X that a .5 instead short circuits me.

[FossilRaist]

I think the zoom of the program is what would normally be my ocular.

So at 10% zoom in the program .5 with the camera and at 1X objective I should have a true magnification of 5X if I'm doing the math correctly.

Z x O x C = M
Z=10
O=1
C=.5
10 x 1 x .5 + 5

Does that sound right to you?

Sorry the missing ocular from the equation really messed me up.

[BramHuntingNematodes]

Personally I would break out the micrometer slide for each individual objective lens, measure the field, with your setup, and use that as a basis for a scale to be included in images. Magnification gets a bit abstract after the image is picked up by the camera sensor, and you would still want to know the dimensions of the field.

[crb5]

Microscope magnification can be confusing, but digital photography has made things a whole lot easier. Take a picture of your micrometer calibration slide using the same setup (objective, ocular (if used), reduction lens (if used) and camera) that you use for your sample. Then use the set scale option to add a scale bar to your sample picture (available with most camera software). This option converts a specific number of pixels to a specific length. If you change the objective lens repeat the scale bar calibration. These settings can be saved for later use – although for accurate calibration it is best to take a picture of the micrometer calibration slide at the same time, since the magnification will change if the camera is not in exactly the same position each time. Once you have a scale bar on the picture, then it will be accurate regardless of what size monitor you view it on, or anyone else views it over the internet.

You don’t need to bother with 20x, 40x etc. labeling for the overall magnification since these numbers refer to what you see by eye and makes assumptions about the close viewing distance being 250 mm for definition of the ocular magnification. These numbers are next to useless in scientific papers where the final picture size is controlled by the publisher (see final paragraph of https://en.wikipedia.org/wiki/Magnification ). The magnification numbers ignore the properties of the camera and any enlargement of the final print out or computer screen size. It may be useful to state the objective magnification for reference, although the numerical aperture is the more crucial parameter (but the latter also requires consideration of the condenser NA for bright field illumination).

If you really want some brain exercise, you can work though the size of the primary image produced by the objective (plus the tube lens for infinity ‘scopes), the size of the secondary image if a relay lens is used, or the photo is taken through the ocular (with or without a camera lens) and the size of the camera chip which captures the final image.
Here is an example. I use a cheap lens-less USB camera with an active sensor width = 3.6 mm positioned at the primary image plane of a finite scope. Using a 10x objective lens and looking through a 10x ocular with a field number = 18 mm, I see by eye a circular field-of-view of 1.8 mm diameter, as confirmed by the graticule. The camera only sees a field number equivalent to 3.6 mm and hence a field-of-view width of 0.36 mm (which is 3.6/18 = 0.2 of the field by seen by eye). So, in one sense the camera adds another 5x magnification and requires a reduction lens of 0.2x to capture the same field as seen by eye. But if the camera image is projected onto a 36 cm (14 inch) computer screen, its 0.36 mm field-of-view would be seen as 36 cm i.e. a 1,000x magnification cf. the 100x assignment for the 10x objective * 10x ocular combination viewed by eye.

[FossilRaist]

Personally I would break out the micrometer slide for each individual objective lens, measure the field, with your setup, and use that as a basis for a scale to be included in images. Magnification gets a bit abstract after the image is picked up by the camera sensor, and you would still want to know the dimensions of the field.

So what you are saying is something I had thought about but thought that would be inaccurate. But it does make sense. Label each as like .7 1, 2, 4.5 or whatever.

Thank you. Sorry if I got frustrating. It's just I've been thinking about this for like a week now and I think the more I think about it the more screwed up I get. It might sound dumb but it's been helpful having this conversation.

[FossilRaist]

Microscope magnification can be confusing, but digital photography has made things a whole lot easier. Take a picture of your micrometer calibration slide using the same setup (objective, ocular (if used), reduction lens (if used) and camera) that you use for your sample. Then use the set scale option to add a scale bar to your sample picture (available with most camera software). This option converts a specific number of pixels to a specific length. If you change the objective lens repeat the scale bar calibration. These settings can be saved for later use – although for accurate calibration it is best to take a picture of the micrometer calibration slide at the same time, since the magnification will change if the camera is not in exactly the same position each time. Once you have a scale bar on the picture, then it will be accurate regardless of what size monitor you view it on, or anyone else views it over the internet.

You don’t need to bother with 20x, 40x etc. labeling for the overall magnification since these numbers refer to what you see by eye and makes assumptions about the close viewing distance being 250 mm for definition of the ocular magnification. These numbers are next to useless in scientific papers where the final picture size is controlled by the publisher (see final paragraph of https://en.wikipedia.org/wiki/Magnification ). The magnification numbers ignore the properties of the camera and any enlargement of the final print out or computer screen size. It may be useful to state the objective magnification for reference, although the numerical aperture is the more crucial parameter (but the latter also requires consideration of the condenser NA for bright field illumination).

If you really want some brain exercise, you can work though the size of the primary image produced by the objective (plus the tube lens for infinity ‘scopes), the size of the secondary image if a relay lens is used, or the photo is taken through the ocular (with or without a camera lens) and the size of the camera chip which captures the final image.
Here is an example. I use a cheap lens-less USB camera with an active sensor width = 3.6 mm positioned at the primary image plane of a finite scope. Using a 10x objective lens and looking through a 10x ocular with a field number = 18 mm, I see by eye a circular field-of-view of 1.8 mm diameter, as confirmed by the graticule. The camera only sees a field number equivalent to 3.6 mm and hence a field-of-view width of 0.36 mm (which is 3.6/18 = 0.2 of the field by seen by eye). So, in one sense the camera adds another 5x magnification and requires a reduction lens of 0.2x to capture the same field as seen by eye. But if the camera image is projected onto a 36 cm (14 inch) computer screen, its 0.36 mm field-of-view would be seen as 36 cm i.e. a 1,000x magnification cf. the 100x assignment for the 10x objective * 10x ocular combination viewed by eye.

Yeah I think I'm going to label the calibration as the objective view.

One question though. If I share an image how would I describe the magnification? would I just list the objective or something else?

BTW thank you for the idea.

[crb5]

One question though. If I share an image how would I describe the magnification? would I just list the objective or something else?

You don't need to state the magnification if a scale bar is included on the image -but could include the objective magnification and how the camera was connected (at the primary image plane, projected though a secondary lens, or taken through the ocular) in the legend .

[LouiseScot]

Don't worry about calculating theoretical magnifications. Just use Fiji / ImageJ together with a micrometer slide to make scale bars via your camera. There are tutorials online and some on YouTube.
Louise

[DirtNerd]

I'm new and had all the same questions. Here are several things that helped me.

First, the thing about magnification. I asked Oliver about this and this is what he said: https://www.youtube.com/watch?v=ceSnCsxbBf0

For focusing this really helped. Focus what you see on screen with the camera first! Then, look through one eyepiece. Focus it. Look through the other and focus it. Your eyepieces and screen should now be in sync.

How to calibrate each objective for measuring: I followed this step by step. It made it easy. https://www.youtube.com/watch?v=Z8652DG249E

[Greg Howald]

You may be over thinking this. We tend to think that reduction lenses on cameras effect the magnification of the image. Not so. The camera does not increase or reduce magnification. The camera will increase or decrease the size of the image. That is not magnification. This is proven with a standard copy machine. Increasing the size of the image with a copy machine does not increase the clarity of tiny things like the details of a dollar bill. Those details do not become apparent when you increase size, but they become apparent when you increase magnification. That's how we catch counterfeiters.
Therefore, when you use a calibration scale at any magnification, one millimeter is one millimeter despite the size of the image seen by the camera.

Usually the camera without the reduction lens will be more consistent with the field of view seen at 40x. With a .5 reduction lens it will be close to the size seen at 20x. But this is the field of view of the camera. It is not magnification.
Good luck. Greg

[FossilRaist]

I finally solved this to my satisfaction. I'm irritating like that in that if I get stuck on something it drives me crazy until I can solve it at least to some degree.

As I had thought I was over thinking it, and in doing so having trouble relaying to others my exact needs to solve the question. Come to find out it was as simple as calibrating with a .5 Barlow and without and comparing the scale between the two. What I discovered is this and this is the important part (the magnification of the AmScope MU1803 is 10X).

Never mind the image you see on your screen that is not what I am talking about. What I am saying is 1mm (any measurement) should match the same from say objective set at 3X and objective set at 3X with a .5 Barlow lens. So 15X should have a scale that matches at 30X.

For me the labeling of the scale along with the magnification is important (at the very least to me). If someone asks I'd like to be able to answer what magnification I was at. It might also help some to understand how small a micrometer is which is another measurement I can now use that I was unable to prior to this. So I needed the equation so I could label each scale (I will use the Barlows often in my basement research). After a lot of experimenting and most of all just clearing my head with the conversation I had here I was able to come to the conclusion of what the cameras magnification is (and maybe I'm still phrasing it incorrectly). It wasn't what I was seeing on the screen that matters in terms of size. The idea was that each and every objective/Barlow configuration was as close to the same as my eyes would allow. I also compared what I was seeing (again not the size just the image)through the camera and the 10X and 20X ocular. The image as I seen is matched the best to the 10X ocular.

So with the different routes I took I came to the conclusion that (the magnification of the AmScope MU1803 is 10X). At least in terms of the equation for magnification. AmScope directly told me the camera has it's own magnification and it also had a .5 reduction. My goal was simply to find that magnification and for my satisfaction I believe I did find that answer.

[MichaelG.]

I finally solved this to my satisfaction. I'm irritating like that in that if I get stuck on something it drives me crazy until I can solve it at least to some degree.

[…]

What I discovered is this and this is the important part (the magnification of the AmScope MU1803 is 10X).

If that description works for you … I am delighted

But I hope you will permit me to explain a little further:

Here is Amscope’s Specification:

Sensor: Aptina AR1820 (color)
Sensor Type: CMOS
Sensor Size: 6.14x4.61mm
Pixel Size: 1.25
Resolution: 18MP
Max Frame Rate: 32.2fps @ 1228x922, 18.1fps @ 2456x1842, 5.6fps @ 4912x3684
Resolution: 18MP
Max Frame Rate: 32.2fps @1228x922, 18.1fps @ 245x1842, 5.6fps @ 4912x3684
Sensitivity: 0.62 V/lux-sec
Connectivity: USB 3.0
Compatibility: Windows (32/64 bit) XP/Vista/7/8/10, Mac OSX, Linux

Ref. __ https://amscope.co.uk/products/18mp-usb ... ction-lens

The two significant items on that list are:
Sensor Size: 6.14x4.61mm
Pixel Size: 1.25 [microns]

Everything else you need to understand about your Magnification is a matter of optics.

MichaelG.