Re: [photo-3d] reverse rings / macro question

[Brian Reynolds <reynolds@xxxxxxxxx>]

boris@xxxxxxxxxxxx wrote:
> A NY mail order house lists a NEW Sigma 50/f2.8 macro lens for $159.-
> 
> That seems quite a bit lower than the 250-350 I typically see for such a
> macro lens.  Is Sigma a cheapo off brand, or do you think this might be a
> good value?
> 

I read good reviews about the Sigma macro lenses when they came out,
but I don't own any of them.

A word of warning.  I don't know where you saw that price, but for the
most part there are only three camera shops in NYC that you should
trust with your money: B&H <URL:http://www.bhphoto.com/>, Adorama
<URL:http:adoramaphoto.com/> and Calumet
<URL:http://www.calumetphoto.com/>.  (Calumet is actually based in the
Chicago area and caters to professional photographers.  They
specialize in Large and Medium Format equipment and do not carry
Pentax 35mm gear.  They do carry Nikon and Canon.)

Most of the other camera shops in NYC have been accused of bait and
switch, outrageous shipping charges, substituting different items or
worse.

A good place to check on the reputation of various photo stores and
products is the Neighbor to Neighbor section of
<URL:http://www.photo.net/photo/>.

> Another question: under the heading macro, I see "reversing rings"
> advertised, for something like $10.  I assume these are for turning
> a prime lens around, for shooting through the lens backwards.
> Retrofocus?  As I would do macros infrequently, is that a good
> solution for doing macros?  It certainly seems cheaper, sounds good
> to me!
> 

I have a reversing ring for my Pentax that I use with the Pentax 50mm
f/2 A lens (manual focus).  It's better than an auxilary closeup lens
or the macro range of my zoom lenses (Takumar).  I don't do much 35mm
anymore so I haven't used it that much.  Definitely more cost
effective than a true macro lens given the amount of use it's seen.

> Finally, what's the difference between getting a macro in 50mm
> f.l. as opposed to something like 100mm f.l. ?  (For stereo I
> imagine the 50 to be better, as one could get a decent stereobase,
> without having to toe-in the cameras as much, because the camera
> would be used closer to the subject.  Are the higher f.l. macros
> mainly for shooting macro at a distance?)
> 

Longer focal length macro lenses let you get further back from your
subject.  Being further back lets you get the lights in closer.
Changing the camera to subject distance also changs the perspective.

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
reynolds@xxxxxxxxx              | "Oooh!"
http://www.panix.com/~reynolds  |    -- Dexter and Dee Dee
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