All of the viewers I have used (or seen) for medium format images
have had a top-loading design. I have seen, however, several
viewers for 35mm images with a side-loading design.

Is there a usability difference between these designs?
Is there any reason _not_ to make a side-loading viewer?
_________________________
John Thurston
Juneau, Alaska

> All of the viewers I have used (or seen) for medium format images
> have had a top-loading design. I have seen, however, several
> viewers for 35mm images with a side-loading design.

I would be hard pressed to think of even a single 35mm viewer with
side-loading design. All the viewers that come in mind are top-loading.

> Is there a usability difference between these designs?
> Is there any reason _not_ to make a side-loading viewer?

I think the top loading design is simpler and easier to use. The slide
does not fall off if the viewer is tipped side-ways (only if turned upside
down). The slide can be accessed over a wider area at the top vs. a
narrow area on the side.

One consideration is the size of the mounts. If the size of the mounts is
not standard, then the difference in design might be an issue. For
example, if some mounts are taller, they will not fit in the side-loading
design. If they are longer, they will not fit in a top-loading design.

George

DrT (George Themelis) wrote:

> John Thurston wrote:
>> All of the viewers I have used (or seen) for medium format
>> images have had a top-loading design. I have seen, however,
>> several viewers for 35mm images with a side-loading design.
>
> I would be hard pressed to think of even a single 35mm viewer
> with side-loading design. All the viewers that come in mind
> are top-loading.

I think 3D Concepts sells a "channel viewer", and I recall Bob
Aldridge showing me some of his panoramics in a folding, plastic
viewer which was side-loading. I suppose they aren't "main
stream" viewers (if anything in this little niche art-form can be
considered mainstream) but they're out there.

>> Is there a usability difference between these designs? Is
>> there any reason _not_ to make a side-loading viewer?
>
> I think the top loading design is simpler and easier to use.
> The slide does not fall off if the viewer is tipped side-ways
> (only if turned upside down). The slide can be accessed over a
> wider area at the top vs. a narrow area on the side.

Thank you, George.

It also occurred to me that many viewers leave the top of the
slide exposed. When the slides are labeled there, it makes it
easy to read the text without unloading the slide.

_________________________
John Thurston
Juneau, Alaska

> I think 3D Concepts sells a "channel viewer",

This viewer is the result of finding a material first and building a
viewer around it. So the side-loading nature is a result of having a
material on hand, not by design.

> and I recall Bob
> Aldridge showing me some of his panoramics in a folding, plastic
> viewer which was side-loading.

This must be the PanaVista viewer:
http://home.att.net/~sales3d/WPanaVista.htm

It is interesting that the panoramic slides are loaded from the side but
the standard "realist format" stereo slides are loaded from the top, as
seen in the pictures in my web site.

Some vintage wood French viewers for glass slides are loaded from the
side.

George

I have a side-loading 35mm viewer which is my preferred viewer for viewing full frame 35mm slides.
I bought it at the 3D Center (Portland), although they probably got it from 3D Concepts - it looks identical to their channel viewer.
http://www.stereoscopy.com/3d-concepts/viewers.html

The slides do not fall out if tilted since it is designed to hold the slide with some tension.
However it is still easy to push / pull the slide out to replace it. It works great with RBT mounts.

I see no reason why building a medium format side-loading viewer would pose any problem,
so long as one accounts for the most common mount heights, as George mentions.

-Bob

>*********** REPLY SEPARATOR ***********
>
>On 6/29/2008 at 1:22 PM DrT \(George Themelis\) wrote:
>> All of the viewers I have used (or seen) for medium format images
>> have had a top-loading design. I have seen, however, several
>> viewers for 35mm images with a side-loading design.
>
>I would be hard pressed to think of even a single 35mm viewer with
>side-loading design. All the viewers that come in mind are top-loading.
>
>> Is there a usability difference between these designs?
>> Is there any reason _not_ to make a side-loading viewer?
>
>I think the top loading design is simpler and easier to use. The slide
>does not fall off if the viewer is tipped side-ways (only if turned upside
>down). The slide can be accessed over a wider area at the top vs. a
>narrow area on the side.
>
>One consideration is the size of the mounts. If the size of the mounts is
>not standard, then the difference in design might be an issue. For
>example, if some mounts are taller, they will not fit in the side-loading
>design. If they are longer, they will not fit in a top-loading design.
>
>George
>

I see no reason why building a medium format side-loading viewer would pose any problem,
so long as one accounts for the most common mount heights, as George mentions.

The main problem as I see it with a side loading MF viewer is that there are at least two mount sizes in common use, and their heights vary by almost half an inch.

 

You would need to engineer a method to keep the less high mount straight in the channel to avoid potentially painful height errors...

 

Since all the mounts are much closer to being the same width, it makes more sense IMHO to top load, which also helps to make sure that the mounts are level in the viewer.

 

The viewer of mine that John saw was indeed the Panavista, which side loads the panoramic images that I make with my twin Widelux rig. The viewer works well for these slides, but the magnification isn't really enough for regular RBT mounted slides (which, as George observed, are top loaded). 

 

Bob Aldridge

---

From: MF3D-group@yahoogro ups.com [mailto:MF3D- group@yahoogroup s.com] On Behalf Of Bob Schlesinger
Sent: 29 June 2008 20:19
To: MF3D-group@yahoogro ups.com
Subject: Re: [MF3D-group] viewer slot question

I see no reason why building a medium format side-loading viewer would pose any problem,
so long as one accounts for the most common mount heights, as George mentions.