Hand Lens Help Needed

Edward Gosfield gosfield at udcemail.udc.upenn.edu
Sat Aug 13 12:42:47 EST 1994


Bill Williams (bwilliam at oyster.smcm.edu) wrote:
: I've used the 10x Coddington for years and have no complaints. 
: Frankly, I've never been too sure what the differences were...
: _______________________________
: Bill Williams
: bwilliam at oyster.smcm.edu
: Dept. of Biology
: St. Mary's College of Maryland
  
supposedly Hastings have a a flatter field, and wider distortionless field
of view per diameter.  Of course they tend to be smaller.  They are
triplets, and therefor can be better corrected.  I have used an Edmund
Hastings 10x for about 15 years, and have been very satisfied with it.  I
have never used a coddington.  

My Edmund catalog says Coddingtons have a central groove cut in a single
element lens, provide a "wider than normal field of view at high power". I
believe that the trade off is better correction and flatter field, with
shorter working distance and smaller field of view (hastings) versus wider
field of view, longer working distance, cheaper price, but more curvature
of field and distortion (coddington).  I don't know how much practical
difference this makes in the field. It depends on what your needs are, and
how particular you are. 

By the way, prices have gone _way_ up on these things.  When I bought my
10x (Edmund)Hastings it cost about $12. They are now about $34. The only
problem I have ever had with the Edmund is loosening of the retaining ring
which holds the lens in place.  The lens began to rattle, and the ring was
finger-loose.  So I tightened it a couple of times, and have had no
trouble since.  It's been in many mountain ranges,bogs, and seashsores.

good luck

eg




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