[Test-Equipment] OT: microscope cameras

[wolfbob]

Dave..

You got me curious. I knew my video camera had a 
"macro-tele" feature but I had never used it and wondered 
how far it would go. I set up the camera (JVC HDD ) on a 
tripod looking at a metal ruler with 1/64 numbered markings. 
The zoom limit on the lens is 32:1 and at 2 ft range, this 
gave 0.8125 inches for the wide part of the 3:4 video 
output. With a resolution of around 400 lines (it will do 
about 800 at mid zoom) this would be about .002 inch per 
pixel. The camera will go to 800x on the zoom, but over 32x 
it is just cropping and processing and not really doing much 
for the per pixel resolution.

This is a low cost camera with a small lens and  I suspect 
that a professional camera with macro lens could do much 
better.

I tried my still digital camera with a 300mm tele lens set 
at macro. From 6 ft I have 1.5 inches the wide way on the 
screen and at 8 MP for the Canon Rebel, this would be .0004 
in per pixel. Again a better lens would help here.

>From what you state below, the cats eye is about 1/3 inch 
and you are looking for 1/100 of that to be 1/10 of the 
screen so I would garner that the per pixel resolution you 
seek is around 0.000075 inch only 30 times better than my 
JVC video and 5 times better than the Canon Rebel. Piece of 
cake.

WBob


----- Original Message ----- 
From: "davec" <davec2468 at aim.com>
To: "Discussion of Electronic Test Equipment" 
<test-equipment at mailman.qth.net>
Sent: Saturday, March 15, 2008 11:06 PM
Subject: Re: [Test-Equipment] OT: microscope cameras


> >My Canon S570IS camera can combine optical and digital 
> >zoom to close
>>in a full image of my cat, Crappie, so that one of his 
>>eyes fills the
>>frame. Do you need real-time video?
>>73 de Mike W5VSI
>
> -=-=-=-
>
> Take that photo of Crappie's eye and blow it up on your 
> computer. Zoom way in. See where one of his lashes meets 
> the eyelid? I need to see objects that size blown up, oh, 
> so it will fill... 1/10 the viewfinder would be OK.
>
> These subjects will be suspended in water in a flask, so 
> focusing distance >0 is important, too.
>
> The suggestion of Wayne's to use a small telescope might 
> be one solution.
>
> All the microscopes I've seen so far expect the object to 
> be a mm or 2 in front of the lens. No can do...
>
> I looked at macro lenses for my digicam but they are 
> available in, at most, 10x. I probably need 200x to 500x, 
> or so.
>
> Still looking...
>
> Thanks,
> Dave
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