[Michael Piziak]

So, is this device for taking a photo that ends up with 2 photos at slightly different angles or what?

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[35mmfilmfan]

'Video not available'

[mlag]

taking a photo that ends up with 2 photos at slightly different angles

Sounds like a stereo or 3d view setup...
There existed units with double lens/camera yielding 2 negatives or with double lens / view splitter onto one single negative...
Like
PENTAX Stereo Adapter 49mm and 52mm reviews - Pentax Camera Accessory Review Database
Or
Stereo Pictures and a camera - PentaxForums.com

See for processing images https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/41652...r-digital.html

[sergysergy]

I cannot see the video either. Is it this one?: PENTAX Stereo Adapter 49mm and 52mm reviews - Pentax Camera Accessory Review Database

[pschlute]

I cannot see the video either. Is it this one?: PENTAX Stereo Adapter 49mm and 52mm reviews - Pentax Camera Accessory Review Database

It is indeed. It was for creating slides which you had to view with the stereo viewer.

[Wasp]

I have always wondered what the target market for these things were. Having a slide with a 3D image is cool, but it probably gets old very fast when you need a special viewer. Scientific research sounds like a better use case, but I have no idea.

[mlag]

I have always wondered what the target market for these things were. Having a slide with a 3D image is cool, but it probably gets old very fast when you need a special viewer. Scientific research sounds like a better use case, but I have no idea.

my feeling is that stereo viewing was a nice gimmick, hence attracted an audience and buyers of this gear at some point in time, but in the end suffered from the fact that you needed a viewer, which is a inconvenience compared to normal photo print viewing...which is easy and universal.

today's version are 3d goggles, as promoted by meta, and the likes...,.but also slow uptake. Meta - VR Headsets, Smart Displays & AR Glasses
I guess the last thing people want is having 500 gram headset on their nose and loosing contact with real world at same time.... maybe nice for one game but nothing to carry around everywhere.

seems history is repeating?

[Bob 256]

my feeling is that stereo viewing was a nice gimmick, hence attracted an audience and buyers of this gear at some point in time, but in the end suffered from the fact that you needed a viewer.............

In my opinion, one of the best ways to view stereo 3D is with a large monitor or on a projection screen. Pretty simple polarizing glasses need to be worn, and they are feather light compared to 3D goggles and work quite well if the system is set up properly. Multiple viewers is no issue, and compared to "glassless" displays, they can be viewed from many angles without the 3D effect dropping out (most recently, there's some development of "glassless" viewing systems which do facial position recognition and track a person's eyes to maintain the 3D effect, but they still have issues with multiple viewers and don't give that good an image due to the use of a lenticular screen over the display).

That said, it's pretty hard to find a 3D monitor anymore. Few (if any) 4K sets allow 3D viewing although they would be ideal for passive 3D since a 1080 line picture can be maintained in 3D (cost though might be a factor for 4K and incorporating a line sequential polarizer screen may pose an issue for 4K screens). Dual projectors are needed for 3D projection unless you happen to have one of the few which came out featuring active 3D projection (and requiring more complicated "active" glasses). The lack of 3D viewing devices (along with other factors) certainly affected the popularity of 3D so now it's back in the sleeping phase.

Stereo photos do need to be converted to mpo files, but that is fairly easy and can be accomplished from those taken with an adapter like the one described in this thread.