200x Microscope under £100? UK

[grepper]

Things to look for when buying usb microscope:

1.   Magnification.  200x is about perfect.

What you want to look for is "optical" magnification, NOT "effective" magnification or "magnification dependent on monitor size". 

Optical magnification is the magnification output of the scope's lens system where it focuses on the scope's image sensor. 

Effective magnification is basically just like zooming in on an image displayed on your computer.  The more the image is zoomed in on, the grainer it gets.  You are just looking at a smaller area of the image and stretching it out to fill the monitor screen.  Very different from optical magnification.

2.   Image sensor resolution.

Higher resolution is better.  If a 20mp image from a modern digital camera is displayed on your computer screen, you can zoom in a lot before the image gets grainy.  But with a low resolution image, like a picture on newsprint, you can see the dots that comprise the image with a simple magnifying glass. 

Higher resolution scope image sensors produce images with more actual image detail.  A 5mp image sensor produces images with more than twice the image data of a 2mp image sensor in the scope.

3.   Other considerations.

With a highly magnified field, ANY movement of the scope or subject is really problematic.  The slightest bump will move the area observed and throw it out of focus.  Without a super stable stand focusing can be a frustrating, hair pulling freak show.  None of the "affordable" USB scopes have a good enough stand.  I made one from a tapping jig. 

Depth of Field:  DoF is the area of the image that is in focus.   We have all seen pictures where the subject is in focus but area in front and back of the subject is fuzzy.  This is the Depth of Field focus area.

When magnification goes much over 200X, DoF becomes EXTREMELY shallow.  At 1000x, you may need to refocus from top to bottom of a single cell.  Even with the tiny aperture of USB scope, much above 200x the DoF is very shallow.  When looking at a rolled edge for example, only the top surface of the roll will be in focus.

With super high magnification, in order to get a complete image of a rolled edge, it is necessary to focus on the top of the roll, take a picture, focus a little lower and take an image...  Then combine all the images in a process called focus stacking.  The are many software applications that can perform that task.

DO NOT get a biological scope.  They are designed for light to pass through the subject, like a blood sample on a glass slide.  All you will get with a knife blade is a silhouette. 

The best images will come from a true metallurgical scope and good focus stacking software.  Let's start at about $700.00.

Most "affordable" USB scopes have a 2mp image sensor.  Not much.  5mp is better.

About the best bang for the buck scope I've found is this one.  200x optical magnification.  5mp image sensor:
https://www.amazon.com/Celestron-Handheld-Digital-Microscope-Pro/dp/B00CMJ1I08/ref=sr_1_1?dchild=1&keywords=celestron+pro+usb&qid=1609376758&sr=8-1

All that said, even a $30.00 scope is way better than no scope and is very informative.

Hope that is helpful!

[ABall]

Incredibly helpful,  thank you for such an imformative contribution.

I hope there will be others like me who will find all of this very useful and I think there will be a few people happy to see you pop your head in, I'm sure someone said you no longer post here, apologies if I've got you mixed up.

All the best.
Alan.

[RickKrung]

Grepper,

Very well said, succinct and clear.  Great to have you back, if even for this little bit.  Do you know if there have been any developments with the Dino-Lite, and similar scopes, that address the issues we had previously? 

Rick

[grepper]

Mr. ABall-

If it helps, all the microscope images in the following post were taken with the scope I mentioned.  Lighting is everything, and I spent a lot of time getting it right.  Used diffused side lighting and it took a bit of messing around.  Shiny steel is difficult to photograph with just top lighting due to reflection.

http://bessex.com/forum/showthread.php?tid=68&pid=510#pid510

Rick-

Good to hear from you!  Nope.  I really have not been keeping up any latest Dino changes.  While beautiful microscopy is always tempting, I pretty much can get what I need from the Celestron and for as often as I use a scope I really can't justify a more expensive unit.

For everyone interested: 

Any USB scope is better than none for understanding edges and sharpening.  A stable stand is extremely important even if you have to make one.  Lighting is everything.  Experiment with side lighting.  Maybe turn off the scope top light.  Put tissue paper over a flashlight, hold it off to the side and move it around until you get the perfect image.  It takes some messing around but even the cheapest scopes can produce informative images.

I'm more than happy to answer any questions I can.  Not that I'm always right, but I'll try.

[Ken S]

Welcome back, Grepper!

For our newer members who might not remember Grepper, if we ever gave a Most Valuable Member award, Grepper would be a prime candidate, and certainly on my short list. Over the years, he has been my computer, digital photography, microscope and battery guru, as well as having a strong influence on me with Tormeks and belt grinders and a friend.

I must confess that my email to him today may have had an influence on his replying. Alan, I was pleased to read the Celestron 5mp digital microscope he recommended for you is the same one he recommended for me. It works very well. Coming from my background of Nikon close up and copy equipment and specialized lenses, I have been amazed with the performance of the Celestron. Ditto Grepper's comment about "the best bang for your buck"!

Thanks, Grepper.

Ken

[grepper]

Aw, shucks Mr. Ken.  Your praise is appreciated but truly not deserved. 

I'm sure a lot of folks here don't know the history, but if anyone deserves recognition it is you for doing such a dedicated and time consuming job of taking over the Tormek Forum moderation after Jeff's departure.  6,800+ posts supporting the Tormek community.  Amazing!  I'm sure everyone here joins me in saying, thanks!

[Ken S]

Aw, shucks, Mr. Grepper......

Ken

[van]

To Grepper:
It is a real pleasure to read your thoughts, which enrich our knowledge and dispel doubts and uncertainties. Learning is our duty, knowing how to express one's thoughts is a privilege of a few.
Thanks

BEST WISHES TO ALL 

[ABall]

Mr. ABall-

If it helps, all the microscope images in the following post were taken with the scope I mentioned.  Lighting is everything, and I spent a lot of time getting it right.  Used diffused side lighting and it took a bit of messing around.  Shiny steel is difficult to photograph with just top lighting due to reflection.

http://bessex.com/forum/showthread.php?tid=68&pid=510#pid510



Many thanks Grepper, I read the thread this morning, it was very enlightening.

Alan