Re: Query: Longer working distance objectives?

From: Aaron (nghy_at_comcast.net)
Date: 06/29/04 

Date: 29 Jun 2004 14:45:17 -0500

Hi Charlie,

Another question, do you need 200X to 400X magnification to do your
work. This is exceptionally high magnification for "physical repair"
with all the related issues such as an extremely small field and the
need for mechanical assistace to move things about.. . Are you
working with micromanipulators?

An old inexpensive used B&L or Zeiss Greenough type stereo microscope
with roughly a 4X objective and 20X eyepieces should provide enough
manification. They come up on eBay failry often. At 80X it is hard
to work without excellent support for your arms and outstanding
eye-hand coordination. You may want to think this out. Try
controlling a slide by hand (unaided by a mechanical stage) under a
40X objective and you will see what I mean.

Aaron

On Tue, 29 Jun 2004 09:28:38 +0100, Charlie+ <charlie@xxx.net> wrote:

>On Mon, 28 Jun 2004 17:57:51 +0100, Charlie+ <charlie@xxx.net> wrote
>as underneath my scribble :
>
>Just to say thanks to you all for your informative replies - the 20x
>eyepieces ( I hadnt' thaught of that!) might be the workaround way to
>go for this occasional use which is for physical repair at these
>magnifications. Stereo option suggested would be marvellous but too
>much for me as non commercial!! I will watch out for any lwd or ulwd
>objectives - Thanks everyone
>Charlie+
>
>
>>I wonder if any experts out there know if there are longer working
>>distance objectives that were produced for 160mm tubelength
>>microscopes in the 20x and 40x powers? And if so what I should look
>>out for on Ebay etc in the way of makes and specific markings on the
>>objectives.
>>Presumably NA figure would be a tradeoff of some description on this
>>type of lens? I also presume there is no work-around to get longer
>>distance to subject from a standard 160 / - objective!?
>>- TIA
>>Charlie+

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