|
|
|
The Vivitar Series 1 Q-dos Lens and My 3d ProjectI wanted to record a 3-D anaglyph image using my Camcorder for a film project. The idea was to create a 50's style movie that could be shown on a TV or digital projection system in 3d with no special projectors. That seemed simple enough. The 3d anaglyph technology has been around since the 1800's so it should be simple.I started researching anaglyph images and lenses only to find that Q-dos was the only lens I could find that actually made anaglyph images. This is a rare lens no longer produced by Vivitar. I got lucky and found a message board post over a year old and emailed the poster, hoping the email might actually still work, asking where he got his because I wanted one, he offered to sell his for $150.00. I thought that was great, the only other place I saw one(out of the whole world/internet only ONE) was for $375.00 so I immediately sent the money. This is where my journey began........ The lens was for a 35mm camera not my pd100a camcorder. I ordered a Teleconverter and a metal 52mm lens cap and created an adapter. Unforunately coupling lenses is not simple and it did not work. I then found out about a product called Nu-View which captured 3d using the LCD shutter glasses. The method superimposed two images and only recorded one at an instant for right and left eye. This looked perfect to modify for anaglyph recording. In theory all I need to do would be to put color filters over the two images for right/left, adjust the mirrors for my point of interest, do not turn on the LCD shutters, and Instant Anaglyph recording. Unfortunately $300 later the Nu-View worked nicely but the anaglyph conversion did not. I had seen an article (in French) by someone that appeared to do this conversion succesfully so I did expect it to work. The modified unit had terrible ghosting and was unusable. No 3d qualities at all in anaglyph mode. I was planning to purchase a new camera anyway so I moved that purchase up some and bought a Canon XL1s which has interchangable lenses. Of course they do not fit the Minolta bayonet of the Qdos so I had to find an adapter. After a lot of searching I found that Novoflex in germany makes a Minolta-XL adapter for the XL1s. This seemed great, they listed a price of 169 euros which is a decent price so I was ready to order, one problem, they dont actually sell any of the products on their website. They directed me to a US dealer that I had already tried with no luck. I called the dealer again and he said it was a special order item and referred me to his sub-distributors none of whom actually sell novaflex products. I then find that Optex in the UK makes a Nikon to XL adapter which is close enough, I can modify my lens to fit if needed. So I find one for sale from a US company for $275.00(quite expensive for a simple adapter but they were the only ones that offered it). I bought one since no one was interested in selling a novoflex adapter to me. It arrived 2 days later and I found out that I never needed it at all. The only reason I spent so much was because I thought the camera needed something to trick the electronic connector on the Lens to work with a manual lens. I did not realize you could ignore the NO LENS warning and the CCD would still work. After fooling with the system a while I realized the 7.2x magnification caused by the adapters length increase to the lens made the system unusable unless you were photographing individual flowers across a football field. There was no way to get a realistic wide shot in even with a wide angle lens. So here I am $1000.00 later with a failed project and a bunch of rare expensive equipment I cannot use. I sold the excess equipment on Ebay and stole the below webpage about the Qdos lens.
The Vivitar Series 1 Q-dos zoom lens 2.8-4/70-210 is a very special lens. There are no similar lenses except a few custom build samples as far as I know.
It not only works as a normal tele zoom lens, but also allows to take ‘3D’ anaglyphic images. It is possible to easily switch between normal and Q-dos (i.e. ‘3D’) modes. This works with any plain single lens reflex camera (Canon, Nikon, Minolta, etc.) and just this single lens. Therefore, it is also called a “Single Lens 3D System”. Common 3D systems require either two separate lenses or an imagesplitter (also referred to as “beamsplitter”) that splits the image frame into two halves. All these stereoscopic systems resemble the two-eyed human vision. Images taken with this lens in Q-dos mode can be viewed as plain prints without problems, but when you view the prints with anaglyphic red/cyan glasses, the photo appears three-dimensional – well, at least somewhat (more on the limitations later) … The Q-dos lens was designed by David Burder and manufactured starting in 1991 for just a few years by Vivitar as a special version of their Series 1 2.8-4/70-210 zoom lens. In case you've already asked yourself: “Q-dos” stands for “Quantum Duplex Optical System”. Articles about this lens appeared in the March/April 1991 issue of “Stereo World” as well as issue 2/92 (July-September) of the German “3D-Magazin”. [Some sample images will be added here later ...] How Does It Work?
At the first sight, the features mentioned before sound very similar to conventional anaglyphic stereoscopy. But how can the images look “normal” without anaglyphic glasses? And how can one take stereoscopic images with just a single lens? Well, when the Q-dos mode is switched on, half red and half cyan filters are placed in the light path within the lens. The result of this is that out-of-focus objects have color “fringes” around them that correlate to the distance away from the in-focus point. On the other hand, the in-focus subject does not have caller fringes. This allows to view the images as plain prints, as the main subject is not affected by the fringes. And when using the anaglyphic glasses, the 3D effect is added by the unsharp fore- and background objects. By the way, the anaglyphic glasses are of the common red/cyan type, so you are not restricted to those included in the lens kit. [Even more sample images will be added here later ...] Idiosyncrasies and LimitationsThe system only works with an unsharp fore- and background and a sharp main subject. While the main subject is photographed sharply in true colors, the unsharp fore- and background objects have red and cyan color fringes. The sharper an object, the smaller the color fringes and the lesser the 3D effect.
Most of the limitations become apparent when reading the following suggestions from the Q-dos manual (cited and translated from my German version):
Note that especially the first three points are in total contradiction to common practices in stereoscopic photography, where the aim is usually to maximize the depth-of-field and to avoid unsharp zones! Having a look at the sample images, one can clearly see an effect called “cardboarding”: The image seems to consist of a number of flat cardboards distributed across the depth range. Cardboarding results when there is sufficient parallax to determine the relative placement of various subjects within the scene, but there is insufficient parallax to see the relative depth within each individual visible subject. E.g. it's enough parallax to tell if a person at 10 meters is closer than a distant background but not enough to get much depth within the image of the person. The centers of the two filters (representing the two ‘pupils’) are about 12 mm apart, far less than the average human eye separation of 65 mm. This limited parallax is a weakness but it may also be a strength: When you do close-ups, you need less parallax or you won't be able to maintain fusion. Another limitation of Q-dos is common to all full-color anaglyphic systems: Colors which are close to the red and cyan of the system's filters exhibit a strong so-called “retinal rivalry”. They appear to jump out of the picture and flash. Obviously, avoiding subjects with those colors helps but is not always practical. To summarize, the restrictions regarding choice of aperture and focal length and the resulting small depth-of-field as well as the cardbording and retinal rivalry effects are actually very limiting, making this lens well suited for only a small set of subjects. LinksWant to know more? Here are some links:
 Example of phots that can be taken by the qdos lens. You need 3d red/blue glasses to view this image in 3d |
