Some Low Budget Imaging Experiments

[desertrat]

Recently bought a 2mp USB eyepiece camera from a Ebay vendor in China for about $25. Paid an extra 32 cents over the free shipping option to reduce delivery time from about a month and a half to about three weeks. It did arrive in about three weeks.

Eyepiece_cam.JPG (46.08 KiB) Viewed 5310 times

It's being used with an old Pentium 4 computer running Windows XP and not connected to the internet. I've already successfully installed an older version of GIMP for image processing that runs fine. Also successfully installed CompineZP for image stacking.

I believe the author of CombineZP has not worked on this program for several years, and the currently available version is several years old, and runs fine on Windows XP. These programs were downloaded from the internet using this computer, a bit newer but still pretty old, and transferred to the old Pentium 4 computer with a thumbdrive.

Before trying to install the software included with the camera, connected the camera to the computer to see if it would be recognized. Windows XP has built in some generic drivers for webcams, and I suspect this eyepiece camera is a cheap 2mp webcam installed in a custom eyepiece shaped housing. Windows did see a USB camera device installed, and clicking on the icon brought up a program window with the camera image and a few buttons, one for taking individual pictures. Adjusting the focus on the microscope was tracked by the streaming image in the Windows camera program, and clicking the picture taking button captured a still image, displayed in the lower margin of the program window. So far, so good.

Trying to install the software was more problematic. The old computer was unable to read the miniature disk, even though the drive is designed for CD and DVD disks and has a receptacle for the miniature disks in the tray. My internet computer was unable to read the disk, either. A newer internet and gaming computer was able to read the disk fine, and the files were transferred to a thumbdrive. The files were transferred to the old computer's hard drive and run, but the install failed with a cryptic "certificate chain validation error".

I suspect the installation program was looking for files specifically on the program disk, or wanted to connect to the internet to validate certificates. Was able to locate an internet source for the S-EYE program in China, downloaded the install file and transferred it to the old Pentium 4 computer with a thumbdrive. Installation failed the exact same way. The program was able to start, but was unable to see the camera. I suspect the installation program wants to connect to the internet to validate certificates.

There are some other possible options, but not pursuing those at the moment because the generic Windows drivers can see the camera and take still pictures. The camera is capable of movies, but can only do 30 fps at 640 X 480 resolution. Still pictures are fine for the time being. The eyepiece camera installed on the 'scope.

Cam_on_scope.JPG (70.97 KiB) Viewed 5310 times

Below is a sample still image from a prepared slide of onion root tip section showing mitosis, quadruple stained, that I bought from Ward's Natural Science company several years ago. The image was sharpened up a bit in GIMP, and contrast and brightness were adjusted a bit also.

Epc_chrm.jpg (27.21 KiB) Viewed 5310 times

The sensor chip is tiny and can only see a small fraction of the field of view in a normal 10X eyepiece. To show that, an image was taken of the same area on the slide using the digital camera and a 10X compensating eyepiece for a relay lens. The lens was not zoomed so the whole field in the eyepiece is visible.

DSCI0571_50p.JPG (56.93 KiB) Viewed 5310 times

These images were taken with a 43X achromat, before my recent purchase of the three apochromats.

I recently bought a 0.3X relay lens, but it won't arrive until the end of the year. It's designed to fit a C-mount camera, so I'll need to cobble together some kind of adapter to use it with the eyepiece camera. If the eyepiece camera sensor sits too deep below the filter mount, it might not work at all. I may eventually buy a 2mp C-mount camera for about the same price as this one, and try it out.

I might also mention that early on, there were some dark spots and strange shadows in the same positions on each image taken with the camera. It turned out the UV/IR blocking filter needed to be carefully unscrewed from the bottom of the camera and carefully cleaned on both sides. I used Q-tips and denatured alcohol, which worked well and didn't damage the filter.

Also successfully processed a seven image stack of a different cell in mitosis with CombineZP. It will be shown in a subsequent post.

[ImperatorRex]

Thanks Rick. Interesting report. Curious to see more after you have received the relais optic.

[desertrat]

The 0.3X reduction lens arrived yesterday. Below is the Ebay listing I used to buy it:

https://www.ebay.com/itm/0-3X-C-mount-M ... 2749.l2649

I ordered it on December 8. Shipping time wasn't too shabby for a low cost item with free shipping.

While waiting for it to arrive, did some searching for more info on the internet. Found an article written by an American importer of these items, microscopes and accessories from China. The article mentioned to beware of cheap plastic reduction lenses with plastic optics that give poor image quality. The units they were selling cost about 3 times what I paid for this one.

When it arrived, though, I was favorably impressed. It is made of aluminum, not plastic, the surface finish is a bit coarse but it is heavily blackened inside and out to avoid reflections. The lenses appear to be glass, and some are heavily coated, giving dark blue and purple reflections from yellowish to white light sources. The upper lens is tiny, only a few millimeters clear aperture, and is mounted in a flat circular cell that appears to be threaded in with two dimples at the edges for a lens retaining ring spanner. I haven't tried to unscrew it yet, but it appears to be threaded.

The lower lenses are larger in diameter and are fairly deep inside the lower opening of the adapter. They appear to be held in with a standard threaded retaining ring with two slots in the periphery for a lens retaining ring spanner. There seemed to be a lot of reflections from the overhead light source. Using a miniature LED flashlight, counted no less than 6 reflections from the lower lens group. All seemed about the same intensity, so the lower lens might be made up of 3 airspaced elements. The reflections from inner surfaces of cemented groups are usually very faint.

So it looks like this reducing adapter has a fairly sophisticated optical system inside. It was made to be used with a microscope camera with a front threaded C-mount, so I temporarily tested it by inserting it in the vertical eyepiece tube and holding the eyepiece camera against the top of the adapter. The image became parfocal with the binocular eyepieces by holding the eyepiece camera slightly above the adapter, with a gap of a couple of millimeters. So it will be possible to make a sleeve adapter to hold the units together.

Got some test images by holding the eyepiece camera against the top of the adapter to keep it steady, and readjusting the focus of the microscope. Image quality was good, I think even a little better than using the eyepiece camera alone. Used it to take the last image in my most recent post in the slide collection thread. With the adapter, the camera can now see about 2/3 of image area seen in the eyepieces.

If I was going to do this over again, knowing what I do now, I would buy a 2 MP C-mount microscope camera that screws right on top of the reducing lens. There are a couple for sale from China for just a couple of dollars more than I paid for the eyepiece camera, which was about $25, and probably have the same sensor and circuit board inside. The mini-disk with driver software looks identical to the one that came with the eyepiece camera.

It looks like for a little over $50, one can separately buy the camera and reduction lens and get usable images from a microscope. Image quality won't be equal to that provided by professional grade imaging equipment, the images won't be quite critically sharp, but they will be good enough to show almost the finest detail that can be seen through the eyepieces.

[ChrisR]

I've been looking for something to get cheap-but-acceptable quality. Higher MP cameras are coming down in price. EG ebay item 323006982235 is £37 = approx $50 for a 5MP.
May be a better start

[desertrat]

I've been looking for something to get cheap-but-acceptable quality. Higher MP cameras are coming down in price. EG ebay item 323006982235 is £37 = approx $50 for a 5MP.
May be a better start

That should be a good camera. The eyepiece adapter contains no optics. As is, the camera would only cover a small portion of the visible field. Using it with the 0.3X reducing adapter should cover almost the whole visible field.