Re: matching camera lenses

[P3D Sam Smith <3dhacker@xxxxxxxxxxxxx>]

>> Sometimes people get the impression that I take any two cameras at random
>> and make a stereo camera out of them... 

>> 
>Sorry Sam. I guess I got that impression from your recent posts on 
>the folding cameras. In a recent post you said you'd found another 
>folding camera of the same brand, but even the shutter was different...

>As you can tell from this tortured reasoning, I never did very well 
>in math! Anyway, I apologize if I've given any offense. 


No offense was taken Gary. I sometimes make things look too easy, when in
fact some people will have certain difficulties with many of the projects
I've tried. I would CERTAINLY DISCOURAGE people to jumping into a siamesed
SLR project as a first project due to the uncountable difficulties that can
arise from this. Start on a simpler project and move up.
>
>But, back to 3D ...
>
> If I bought two 50mm lenses of the same make and model, do you 
>think I'd stand a chance of it working? Would buying two new ones 
>from the same dealer at the same time (thus improving chances that 
>the two would be from the same "batch,") make it any more likely that 
>they would match? I mean, I'm probably going to try this anyway, but 
>right now I'm having "pre-purchase anxiety."

Accurate lens testing in the store is almost impossible when it comes to
matching lenses. But you can try this:

1.  Bring a cheap roll of color film to the store with you.
2.  Load up the camera and set it up on a tripod to set a shot out the
window of a static scene. 
3.  Bang off the roll with different lenses, making sure you can identfy
which lens took which frame, and make sure they are all focused at infinity.
4.   Have the film processed DEVELOP ONLY. 
5.   Cut each individual neg out at the borders. Overlap the negs on a light
box two at a time. If you find two that match up perfectly, you've got two
matched lenses.





The 3D Hacker
website: http://www.cadvision.com/3dhacker/index.htm


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