T3D Re: camera focal lengths

["Greg Wageman" <gjw@xxxxxxxxxx>]

From: Greg Erker <erker@xxxxxxxxxxxxxx>


>>And this brings us to RBT cameras.  There aren't any fixed-
>>focal length 70 mm lenses on the market that I am aware of
>>but one option on an RBT is a zoom which includes 70 mm.
>>Another option is fixed 50 mm lenses of good quality which
>>ought to be great in a hand viewer.  But getting back to the
>>zoom lens, what is the distortion like at 70 mm?  I wouldn't
>>be very interested if the distortion is more than 1 or 2%.
>>Anyone have one of these things?  Anyone tested it?
>
>  Has anyone tried a 50mm lens with 1.4x teleconverter?
>I would expect this would give better results than a
>zoom lens.


I have an RBT X2B with both 50mm fixed-focus Ricoh lenses, and Tokina
28-70mm zooms.  In a completely subjective test where I photographed the
same object, from a tripod, using Kodachrome 64 film with both lenses, I
could detect no subjective difference between the images.  Frankly, this
surprised me as I have always heard that zooms are at best a compromise
and fixed-focal-length lenses perform much better.  The images are sharp
and contrasty.

Of course, one possible explanation is that the Ricoh lenses suck. :-)
However, I've also heard good things said about their glass, so I'm not
sure that's the explanation.

     -Greg W. (gjw@xxxxxxxxxx)




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