Modifying the Loreo LIAC for wider angle pictures.This page requires a monitor width of at least 1000 pixels in order to see both images for cross-eyed stereo viewing. Since the photos also have large vertical dimension, it helps to toggle the "full screen" view (F11 in Windows). However, if you haven't mastered that viewing method, these pictures may also be appreciated as 2d flat photos. All are © 2008 by Donald Simanek.
For instructions on free-viewing 3d by the cross eyed method, see the How to View 3D page.
One of the important characteristics of a stereo photograph is the horizontal angle of view. If it is too small, the picture seems "cramped" and the sensation is of "looking down a tunnel". On the other hand, excessive "wide-angle" stereos have a different sort of artificial feel to them. When we view a scene in nature, the peripheral areas of vision have negligible stereo depth. Here's some data and calculations:
* The Loreo 9008 Digital Lens in a Cap was announced for sale in mid 2008. On July 14, 2009, after a year of delays, Loreo announced that due to production problems the product was being withdrawn. Apparently none were ever sold, though a few were loaned to beta testers.
** Focal length of lens of a 35mm film camera which would give equivalent results.
*** The archaic designation of sensor sizes. For an explanation, see sensor sizes.
So we are stuck with the old model Loreo LIAC, which had several deficiencies that the new Model 9008 was supposed to address. The old LIAC had smaller ineraxial (60mm) than the human eye (64mm). It had 38mm focal length lenses, producing a narrow angle of view, only about 17°, compared with the stereo realist (36°). This is a result of the half frame image on the camera's sensor, and the rather long (38mm) focal length of its lenses. It had only three distance settings: flowers (1.5m), people (3m), and distant (infinity), and two manually-selectable apertures, f:11 and f:22.
The Loreo 9008 had 25mm retrofocus lenses, for a 25° horizontal angle of view. Three manually selected apertures were provided, f:8, f:11 and f:16. Its front housing had threads for 52mm accessories. It was even suggested that one could attach two of the rather common 0.7x wideangle adapters, with 52mm threads, which would increase the horizontal coverage to 36° horizontal, nearly exactly matching the old Realist "standard". The 9008 also was supposed to have 64mm interaxial, matching that of the average human eyes. (The old LIAC had 60mm interaxial.) All this was enough to get us eager to buy one.
There are important advantages for a 3-D beam splitter device with a digital SLR compared to the alternatives. Both pictures are simultaneously captured by the single shutter. (Dual-camera rigs require electronic synchronization, usually with a rather expensive additional device.) The lens-mirror viewfinder can be used comfortably in bright daylight or dark scenes. (LCD screen viewing is useless in bright daylight.) The adapters are lightweight and compact.
But it was not to be. So it's back to the drawing board for Loreo, and for those of us who yearn for wider angle stereo photography.
The old Loreo LIAC and the mythical 9008 both had similarities of design. So why couldn't one use a pair of wideangle adapters on the old LIAC? An immediate problem is that the LIAC lacks threads for accessories. The second problem is that half centimeter protrusion on its case between its front windows which prevents one from mounting anything close to its front windows.
Typical 52mm threaded wideangle adapters have front threads of 62mm, and a front diamter of 64mm. So butted together they'd have an interaxial that's ideal. Unfortunately the LIAC has a 60mm interaxial. Will that be a problem? Maybe not; only experimentation will tell.
My first tests were intended to avoid surgery to the LIAC. That could come later. I'd been informed by someone who had taken one of these apart that the central protrusion on the LIAC case has nothing important within it. So it could be removed with Dremel tool or hacksaw, leaving a flat surface in front of the windows so the wideangle lenses could be closely fitted to it. But for now I mounted the two wideangle adapters in a metal frame made from Meccano parts, and located it as close to the LIAC as possible, being careful to center the LIAC windows symmetrically in relation to the lens centers. I looked through the camera viewfinder to equalize the vignetting at the corners of the images.
Also, since there's a half centimeter space between the wideangle lenses and the LIAC, I used a black cloth wrapped around that space to block entry of stray light.
Results: A failure. The stereo was fairly good, but the images lacked the sharpness of the unmodified LIAC. Perhaps that's due to the excessive distance of the wideangle lenses from the LIAC. And that pesky unsharpness in one image, common to all the Loreo devices, was made worse. That could even be due to the fact that these were low end wideanagle adapters, costing only $40 each. The barrel distortion of the lenses was apparent at the top and bottom of the images, but in most cases I'd crop the images to square format.
Note the unsharpness at the left of one picture and at the right of the other. This is the fault of the wideangle lenses and the fact that their optical centers are 64mm apart while the LIAC has its axes 60mm apart. It is also compounded by the wideangle lenses being too far from the prime lens. I find it remarkable that when viewing these in 3d you don't notice that defect, even though the lack of sharpness is quite serious when viewed 2d. The brain compensates when one eye's image is unsharp. Still, I don't consider these results acceptable for serious photography.
I had considered further modifications:
A suggestion to LOREO. The Loreo 3d cameras originated in the days of film photography, and were marketed to people who wanted only 3-D prints without the fuss of mounting the pictures themselves. Just take the film to the one-hour photo, and then view the prints with one of Loreo's inexpensive viewing devices. Then LOREO introduced the LIAC 3-D adapters, which, for technical reasons, were only intended for use with Single Lens Reflex cameras, and sold with bayonet mounts for Pentax, Nikon, Canon and Minolta cameras only. Still the final product was expected to be prints, with the images in L-R order, so that the simple viewing devices could be used. Because of that requirement, the Loreo LIAC had to have mirrors arranged to interchange the pictures Left and Right on the camera's sensor.
Those days are no more. It's the digital age in photography. Loreo modified the LIAC device to work with the 3/4 size sensors of digital SLRs. Still the system was wedded to the notion that pictures will be viewed as prints, with the pictures in L-R order.
It's time to get fully into the digital age. Someone should produce a 3-D device that will fit on digital SLR cameras, and produce pictures in R-L order. This would eliminate the engineering compromises required by mirrors to interchange the picture's order. Forget prints. With products such as StereoPhotoMaker (free) users can take the images from the camera and output them in any format required, for parallel viewing, for cross-viewing, anaglyph (yechh!), etc. And yes, even Loreo viewer compatable prints.
The device should produce pictures with a horizontal angle of view of at least 36°, but 40° would be better. Dare we hope for a device that would interface with the camera's autofocus capabilities?
The optical components, lens, mirror and front filter rings should be securely positioned on a metal frame. The front filter rings should be metal also. The outer housing can be plastic.
How to achieve this? Well the mythical Loreo 9008 had retrofocus lenses for 25mm focal length, and these lenses were at the rear of the device. But a retrofocus design could easily have the front lens element (two of them) at the very front of the beam-splitter (where the current Loreo LIAC beamsplitters have plain glass windows to keep out dust).
Or consider using an anamorphic design to squeeze the images horizontally. This is the method used in movies for the old Cinemascope films, and still used in film production. (Again, the front glass windows could be front lens elements, negative power cylindrical lenses in front and a positive power cylindrical at the back, along with the prime lens.) The digital images could then be unsqueezed digitally with your computer. If such a device were available, I'll bet that stereo imaging software would soon incorporate an unsqueeze option, for any degree of expansion you require.
The pictures would be usable with any current (or future) stereo viewing system. With no "processing" at all, pictures in R-L order are immediately viewable on a computer screen using the cross-view method.
I know, such a device would sell for maybe twice as much as the Loreo 2008. Perhaps $300. But it would at last be 3-D of interest to professional photographers and serious amateurs, who are willing to pay big bucks for a high quality system. After all, any good quality lens for a digital SLR will easily cost $300 or much more.
So get with it, Loreo. We will be eagerly waiting.
Now [October 2009] it may be too late for Loreo to capture this market. The Fuji 3D W1 camera has been released. It does nearly everything sereo photographers wanted and it has a reliable autofocus for 3d as well as 3x optical zoom. It's pricey, at $600, and some may still want a device with comparable results to attach to their SLR cameras. And such a super Loreo might well cost as much as the Fuji 3d, if it has comparable features.
All pictures on this page © 2008 by Donald E. Simanek.
More cross-eyed stereos in 3d Gallery One.
Input and suggestions are welcome at the address shown to the right.