Re: Stereoscopic Photography


<pooua@xxxxxxx> wrote in message
news:1132012067.164996.276270@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Neil Harrington wrote:
>> <pooua@xxxxxxx> wrote in message
>> news:1131853376.980291.162470@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
>> > They also sell lenses that fit on regular film and digital cameras. In
>> > fact, I am considering the purchase of their lens designed for use on
>> > 1.6 factor digital cameras (such as the Canon 20D that I just placed on
>> > order this afternoon).
>>
>> Is that their "3D Lens-in-a-Cap"?
>
> Yes.
>
>> Those so-called beam-splitters work, all right, within their limitations.
>
> Thanks for the discussion. These are important considerations.
>
> In 2 months, I plan to spend 2 weeks island-hopping around Hawaii. I
> plan to visit at least 6 of the 7 islands. I would really love to be
> able to take some great stereoscopic images.
>
> I have a Canon Rebel G 35 mm film camera and I've placed an order for a
> Canon EOS 20D digital camera. If those are not up to the task of making
> good-quality 3D photos, I am open to buying another camera, as long as
> it is not too expensive (below $200).

It probably wouldn't be quite within your price, but you might want to take
a look at some of the Pentax digital compacts that have a 3D feature. What
that does is divide the frame in the same way that one of those
beam-splitter gadgets does, but of course you cannot shoot both sides
simultaneously. The left side appears first on the LCD monitor, you shoot
that, then shift to the right and while the left half remains on the monitor
as a guide, shoot the right half. It actually works very well, though
shooting hand-held it's hard to get every stereo pair just right. (But hey,
that's the beauty of digital, right? It's not like you're wasting film.)

I got a Pentax Optio S4i with this feature to try it out (boy, is that a
tiny camera! but the monitor is big for the camera size, which is important
for this). It worked so well I got a Pentax Optio 750Z with the same
feature. What's great about this is that you end up with a stereo pair
ready-made in one frame, so you can just have a standard 4x6 print made at
Wal-Mart or whatever and then all you need is a prismatic viewer. The 4x6
print of course crops a little off the top and bottom of the 4:3 frame, but
that's fine as it leaves you with two 4:3 vertical images within the 3:2
horizontal, if you see what I mean.


>
> I have a Minolta Dimage G500. If I were crafty, I could buy another and
> mount them on a rail... But, that might be awkward to carry around, if
> not use?

Yep. Awkward. I have a couple of near-identical Minoltas, a Dimage Xt and an
Xg, same lens and same resolution, and I've been thinking along the same
lines as you. But I can't for the life of me figure out how to trip both
shutters simultaneously, or near enough to simultaneously.


>
>> >> wide-eyed prints are the most relaxing to view but a limited in size
>> >> to
>> >> around 7cm wide.
>> >
>> > How would one view these, exactly?
>>
>> With a prismatic viewer, such as sold on that site.
>
> You mean, the PokeScope?

No, just a plastic hand-held viewer with two mild magnifying lenses (to
shorten focus) which also have a little prism built in to cause the lines of
sight to diverge slightly. Very inexpensive, I saw one model on that site
for $3.00 which is exactly what I use and it works great for this. Wait . .
.. checking just now I see they sell it as the "Deluxe Stereo Print Viewer,"
code SVN-DLOR. It looks exactly like the ones I use. They also have a
cheaper model, the "Stereo Print Viewer" code SVN-LORG. I have one of those
too and it's okay, but a bit too small in my opinion.

>
>> The *best* way to view full-size side-by-side stereo pairs on a computer
>> monitor, IMO, is to get a PokeScope. They're on that site also, or you
>> can
>> order direct from the maker (same price, as I recall). For the $10 extra
>> I
>> suggest getting the software too.
>
> Hmm... $40 ...
>
> You say it is possible to view these images without the glasses? Maybe
> a *** of paper?

You can free view stereo pairs fairly easily if the images are small enough
and homologous points close enough so that your eyes don't have to diverge.
What you have to do is look straight ahead more or less, but let your eyes
come to a near focus rather than looking at infinity as would normally be
the case with the axes of your eyes nearly parallel. This is actually easier
if you wear bifocals or reading glasses, since the short-distance
prescription takes care of focus more or less automatically, and all you
have to do is relax your eyes until their lines of sight are about parallel.
I think most people will quickly get the knack and have no trouble at all
once they do. But again, this means using small images, preferably about 2
3/8" in width for each half of the stereo pair. The advantage of the
prismatic viewers is that you can use somewhat larger images which will show
more detail, and you don't even have to pick up the knack as the viewer does
it all for you.

As for using a divider (I assume that's what you mean by the *** of
paper), I've never found it necessary. It's true that the old Holmes
stereoscopes used a partial divider, but I doubt it was really necessary.


>
> What is a good way to send stereoscopic images to young children?

Beats me. I think there the problem would be getting young children to
understand the point of the thing, but if they've used ViewMasters and get
the point of 3D that might take care of that. Another problem might be that
really small kids have a shorter interocular separation too. I was showing
some Realist-format stereo slides to my nephew and his kids once, with a
viewer for such slides, and his smallest girl's eyes were too close
together--she could only look through one eyepiece at a time.


>
>> > I might make an exception for the ViewMaster reels. I have always been
>> > a fan of ViewMaster. Now, as an uncle to 4 children under Age 7, I
>> > could probably be a big hero if I made up some reels...
>>
>> That's quite a task!
>
> It looks easy... really, how hard could it be?

First you'd need a ViewMaster camera to take the stereo pairs. Then you'd
have to have the transparency film developed but not mounted, unless you
could find a service that did that kind of mounting. Then you'd have to cut
the little chips out of the film and mount them very precisely in the reels.
That looks easy to you? The very thought of it makes my teeth hurt. Mounting
Realist-format slides is hard enough, but there at least you're working with
relatively large 23x24mm film chips. I have no idea where you'd get the
necessary supplies for ViewMaster, though at one time they did sell the
cameras and mounting equipment. That was long ago.


>
> [snip]
>
>> There was also a really nifty device called the View Magic, made by
>> Dimension Press, for viewing a stereo pair of 4x6 prints over and under.
>> It's perfect for any sort of slide-bar or side-shifting stereo
>> photography.
>> Unfortunately I think they've gone out of business and I don't know of
>> anyone who makes such a contraption now.
>
> Thanks, Google...
>
> http://www.rmm3d.com/viewers/vm.econ.html

That's it! Though mine doesn't have that stand, which looks like kind of a
kludged-up affair anyway.

I'd looked for Dimension Press and couldn't find 'em, which is why I assumed
the View Magic was no more. I will probably buy another one just for a
spare, as there isn't anything else like it to my knowledge and the
over-and-under arrangement neatly solves the problems of limited picture
width which are intrinsic with other kinds of stereo print viewers. Thanks
for the heads-up!

Also, I notice that site gives you a chance to try out free viewing, on the
two right-hand images. Does it work for you?


>
> The standard size is only $35...

Just five bucks more than I paid for mine, several years ago. Definitely a
must-have if you're interested in slide-bar stereo or any similar method,
IMO.

Neil





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