[OM] Re: Buying a Tamron 80-200 f2.8

[Chuck Norcutt]

I'd forgotten about that.  You have a good memory.  I guess the original 
page has been deleted but I sort of re-created it.  I've re-posted the 
two photos that comprise the test plus a 1:1 pixel crop of the center 
sections.  They are of a rhododendron blossom taken with the Mynolta A1 
in macro mode at 50mm (200mm eguiv for the A1).  One has the lens 
unobstructed and the other has a square of black electrical tape stuck 
(if I remember correctly) about 1/2" (12.5mm) square stuck to the front 
element.  That's a pretty substantial obstruction to a front element 
that's about the size of a Zuiko 50/1.4  Counts for lots of dust specs.

I think the first image on the left is unobstructed and the one of the 
right has the tape.  But I really don't remember which was which and I 
can't really tell.  But that was the purpose of the exercise wasn't it?  :-)

Here they are:  <http://www.chucknorcutt.com/dust%20spec%20test/index.htm>

Chuck Norcutt

Moose wrote:
> Chuck Norcutt wrote:
>> You could put 100 large dust specs inside the lens and never notice the 
>> effect on image quality.  
> What happened to your samples images with and without a big piece of 
> black tape on the front element of a lens? That was a great example.
> 
> Moose

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