usb digital microscope

[csb (Craig)]

I have a Brightwell BW908C usb digital microscope and I am wondering if it is actually 400X as advised on the box and in the manual.

I have attached an image taken with the microscope using the Brightwell imaging software.

It is an image of pages from a 400 page book. I counted ten pages and marked the edges of the 1st & 10th pages of this group with a black texta. I measured the thickness of the ten pages at 1mm (nearly exact) with a metal ruler.

Then I took an image of the pages with the microscope set at 400X, which is the image posted. The dark lines are pages 1 & 10. Measurement, from outside edge of each line, is just under 10cm on my computer screen.

Obviously this is not 400X 1mm!

So is my understanding of a microscope magnification power incorrect?

I can enlarge the image to 1600x1300 which makes it visually larger between the lines but with big loss of resolution - already you can see pixelation? in the posted image.

On the net I found some images of coins and print that was supposed to be 200X with a digital microscope - my microscope can take images with similar detail and resolution.

(I just checked the posted image and it is the same size as original when viewed on my pc. Also if you click to enlarge then that is basically same size image, and appearance (pixelated), as the 1600x1300.)

[AndrewJ]

Gday Craig

So is my understanding of a microscope magnification power incorrect?

In this case, probably yes.
When using a "digital camera" in conjunction with a "lense system"
the controlling factors are
a) the focal length of the optics
b) the individual pixel size on the CCD/detector
c) the absolute size of the detector.

The field of view is tied to the focal length and total detector size.
The resolution ( in arcsec/pixel ) is tied to the focal length and pixel size.

The latter is more analagous to "magnification factor" but its not quite the same thing.
The smaller the arcsec/pixel, the better the detail you will see,
but its not really "magnification" in the sense of looking through an eyepiece with a MkI eyeball.

Andrew

[sheeny (Al)]

G'Day Craig.

I have the older brother of your microscope. Mine only takes a 640 x 480 image ( and mine is touted as a 50x and 200x). In mine, the same mechanism controls both focus and magnification. It is therefore impossible most of the time to achieve the quoted magnification. I can only assume it is possible at some extreme focus condition, but I haven't proven it.

Under normal conditions, magnification will always be less than the quoted figure.

Al.

[jjjnettie (Jeanette)]

Is anyone else thinking "Guide Scope"?

[csb (Craig)]

Looks like only you JJJ

Thanks for your replies but none the wiser

I found some forums that say at 400X you should be able to see blood cells. So I will have to work out how to do that - probably need to smear some blood on a slide or smear blood & water on a slide. We shall see.

Al, my microscope has the same type of focus with the object magnified at 20X & 400X. Could I ask a favor? Have a look at pages of a book, where 10 pages = 1mm, and tell me if the result is the same as mine.