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Vivitar Series 1 Q-DOS 70-210mm F2.8-4.0 Review RSS Feed

Vivitar Series 1 Q-DOS 70-210mm F2.8-4.0

Sharpness 
 8.3
Aberrations 
 7.7
Bokeh 
 7.7
Handling 
 8.0
Value 
 6.0
Reviews Views Date of last review
3 39,271 Mon May 28, 2012
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Recommended By Average Price Average User Rating
67% of reviewers $295.00 8.00
Vivitar Series 1 Q-DOS 70-210mm F2.8-4.0
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Description:
This is not only the Cosina-made 5th version of the well-respected Series 1 70-210mm zooms, but also is uniquely capable of capturing red/cyan anaglyphs in a single shot.

The lens has 14 elements in 11 groups, does macro to 1:2.5, is lighter than the first 3 versions, and takes a smallish 58mm filter. Macro does not have a separate switch, but is entered via simply focusing past the normal near stop when the lens is set at its maximum focal length.

The Q-DOS anaglyph support consists of a segmented half red, half cyan filter that is internally inserted/removed near the aperture blades by a QDOS/normal switch (right in photo). Q-DOS is only recommended to be used at focal lengths between 135-210mm (marked left in photo), with the lens close to wide open, and the subject fairly close. The captured images need no special processing, but are directly viewable stereo anaglyphs using red/cyan glasses.
Mount Type: Pentax KA
Price History:



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Pentaxian

Registered: July, 2011
Posts: 2,377
Review Date: May 28, 2012 Recommended | Price: $300.00 | Rating: 7 

 
Pros: workes OK
Cons: fell apart
Sharpness: 7    Aberrations: 7    Bokeh: 7    Handling: 6    Value: 6   

I added this lens to the S1 28-105 some years ago. Quality of images was much better. The design is nice and the lens feels quite solid. After a couple months (new lens) the lens tubes came apart. Two weeks later the lens was stolen and I did not replace it with a new S1.
   
Forum Member

Registered: February, 2011
Location: Minneapolis
Posts: 58
Review Date: May 10, 2012 Recommended | Price: None indicated | Rating: 8 

 
Pros: Good build quality, sharp
Cons: CA wide open
Sharpness: 9    Aberrations: 7    Bokeh: 8    Handling: 9    Value: 9   

I bought this lens new in 1989 for my Pentax film SLR. I gave up on photography, and then over 20 years later, I bought a DSLR. Because I had this lens, I chose to go with Pentax. I started with a K-X and recently upgrade to a K-7.

Although I do not have the Q-DOS version, mine is otherwise identical. This lens has been given a bad reputation coming after the first 3 versions, but it really is not a bad lens. It can be picked up for about $30. and it is nearly indestructible. I use it mostly for macros. It has a nice bokeh and is sharp.

If you come across one, mostly likely for pocket change, give it try - you won't be disappointed for the price.
   
Junior Member

Registered: August, 2009
Location: Lexington, KY
Posts: 30

3 users found this helpful
Review Date: January 22, 2011 Not Recommended | Price: $290.00 | Rating: 9 

 
Pros: Fast, good IQ, macro, 3D support
Cons: Poor 3D IQ, rare and expensive
Sharpness: 9    Aberrations: 9    Bokeh: 8    Handling: 9    Value: 3   

This is a very rare lens; no more than 5 show-up on eBay each year. I've been doing research involving the out-of-focus portions of images, and this is the only commercial example of a closely related technology, so I paid the full buy-it-now price when I found one in excellent condition including the box and manual. My copy happens to be Minolta MC mount, but my evaluation is using a glassless adapter to a Sony NEX-5, so my comments should also apply to K mount copies on Pentax....

Build quality is excellent. I have 3 other Series 1 70-210mm lenses, all version 1; being lighter and having a simpler way to enter macro mode makes this lens even a bit better ergonomically, although it's still big and heavy. My copy works very smoothly, but has serious zoom creep when pointed up or down.

IQ is very good on my other versions, especially close-up. This one seems to be tuned for a little more distant subjects, but IQ is good even wide open and very close-up:



but that isn't enough to make this lens worth the nearly 10X cost over version 1. It's the Q-DOS feature that justifies the cost: the ability to create stereo anaglyphs for 3D viewing directly in-camera. Move the QDOS switch into position and the above becomes:



In theory, the red/cyan filter should cause no loss of sharpness and only about 1 stop of light loss. Unfortunately, the light loss is more like 1 2/3 stops and the IQ is destroyed. Yes, destroyed. It is terrible! I'm not sure why. It does seem that focus shifts slightly when the QDOS filter is inserted, but saying anything is in focus is being very generous. The opposing half-circle PSF (with some cuts in it to allow filter insertion/removal) definitely produces terrible nisen bokeh and certainly doesn't help sharpness. Whatever the cause, the in-focus part of the image looks like it was shot through a frosted window. 2D images use most of the resolution of a 14MP sensor, but 3D can barely make a decent 640x480 pixel image... although it does show depth.

A search of the WWW quickly confirmed that this isn't a problem specific to my copy. Every 3D image I found taken with a QDOS had the same remarkably lousy resolution, although it wasn't always obvious in images scaled for WWW display....

Ok, now to my research. Using the same basic principle that the QDOS lens used, I've been capturing single-shot analglyph images by trivially adding a filter to the front of a lens. I have written-up the technique as an Instructable so others can easily use it too; the front filter costs less than $1 to make. This front filter approach can be used with any of a wide variety of lenses. So, how well does the QDOS lens work when using it in normal mode with an external filter to implement the anaglyph capture?



Obviously, it works much better than using the built-in QDOS filter. Good for my research, bad for my investment in this lens.

Actually, the QDOS lens isn't the easiest lens to use with an external anaglyph filter because the filter needs to keep its orientation but the lens front rotates during focus. For example, a 135mm f/3.5 Takumar is a lot easier to use with the external filter and produces anaglyphs that are of comparable quality.

So, do I recommend the QDOS lens? No, not as a "user" lens. The 2D performance is actually quite good, but not at $290 when other versions can be had for closer to 1/10 of that price. On the other hand, it is a great collectible.
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