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Vivitar (Kobori) 28-105mm F3.5-4.5

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4 38,060 Tue September 8, 2015
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100% of reviewers $38.67 8.00
Vivitar (Kobori) 28-105mm F3.5-4.5

This review page is for the Kobori made (77xxxx serials) lens with a 72mm filter. The earlier 9xxxx serial lens with a 67mm filter was made by Cosina and is reviewed here. Later a Cosina made 28-105mm f/2.8-3.8 AF lens was issued under the Series 1 label.

push-pull zoom
15 elements in 14 groups.
CFD 2m
6 blade iris
72mm filters
1:5 macro setting at 105mm (CFD 0.75m)
aperture ring f/3.5-22 plus A
Kobori mfr, serial number begins 77

The Kiron 28-105mm is reviewed here.
This lens can have the overlarge aperture lever guard, which will prevent the lens mounting properly on dslr, see here.
Mount Type: Pentax KA
Price History:

Add Review of Vivitar (Kobori) 28-105mm F3.5-4.5
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Registered: August, 2012
Location: Dartmoor, UK
Posts: 2,555
Lens Review Date: September 8, 2015 I can recommend this lens: Yes | Price: $15.00 | Rating: 8 

Pros: Surprisingly sharp for the price.
Cons: Weak contrast.
Sharpness: 8    Aberrations: 8    Bokeh: 6    Handling: 7    Value: 10    Camera Used: K10D   

Mine is the Kobori version with the 77x serial number and 72mm filter ring.

I got this lens for 10 from a local market and honestly wasn't expecting much, but it has turned out to be a very pleasant surprise. For my needs, it's sharp enough in the centre wide open and at f/8 it's sharp across the frame throughout the zoom range. I'm not a bokeh obsessive, so all I can say on that subject is that out of focus areas are rendered smoothly enough for my taste. Contrast is quite weak, with the lens being prone to veiling flare across that huge front element, so a decent lens hood is a must. Chromatic aberration is remarkable by its apparent absence in every shot I've taken so far.

The construction quality is reassuringly solid feeling, and the handling is what you'd expect for a fully manual push-pull zoom: forward for telephoto and back for wide angle. It's a big, heavy lens with a tendency for the zoom ring to slip forwards and backwards by itself whenever the camera is tilted up or down.

Colour rendering is pleasantly rich with a definite tendency to emphasise the greens, but that's easily fixed in post-processing. You'll probably find that you need to add some contrast in post as well.

If you can get this cheaply enough, go for it. Don't expect it to be the mythical "stack of primes" because it's a very long way from being that, and any modern zoom covering the same range is likely to be better. Just accept this lens for what it is: a very useable vintage zoom that's capable of producing entirely acceptable results as long as you work within its limitations.
New Member

Registered: April, 2014
Posts: 11

1 user found this helpful
Lens Review Date: November 26, 2014 I can recommend this lens: Yes | Price: $41.00 | Rating: 8 

Pros: Light, wide range of focal length, Good quality of picture
Cons: manual focusing
Sharpness: 8    Aberrations: 8    Bokeh: 9    Handling: 8    Value: 10    Camera Used: Pentax K20D, Canon 60D   

I got one of this kind of lens last week. It cost me $41 include postage after a negotiation. I would like to give it an overall rate between 8~9, mostly 8.5 or 8.6. A complete information about this lens may be:

Vivitar Series 1 28-105mm F/2.8-3.8, Filter size 72mm, P/K mount with "A" mark on the aperture ring

Yes, it is the version of filter-size in 72mm, which has been commented as worse by some people worldwide. I was also disappointed at the first with it since the pictures were sometimes blur and very bad just like what the other peoples have said. But today I finally found a problem of this lens. It is the focusing issue and is very easy to be corrected. The issue is that it may give me twice confirmations when I turn the lens to focus on an object. One is true and correct and the other is false and wrong.

With my experiences, when I turn the lens from right to left to focus an object, it gives me a confirmation at a "shorter" distance from the object, so the picture is blur, but when I turn the lens from left to right, it will focus in an exact distance and produce a very sharp picture. I did in many times to make sure my judgment is right. I even posted several photos onto a forum in a Chinese society. I also created a picture to show the evidence of the twice confirmations of the focusing issue. The website link is as blow:

Although you might not be able to understand the Chinese texts in the website, you can see a complete information of the lens, all the pictures taken by it and the relevant photographing parameters. You can even find the environment, i.e. sunny, breeze, tripod, ISO, focal, exposure, aperture, etc., from the texts and title of each picture.

So now, in my opinion, this lens is a good lens, not a bad one. You can see the IQ is very good even in the wide open of the aperture 2.8 at the Focal 105mm, and the color rendition is very nice. Of course the bokeh is amazing, too. Especially when worked with its macro, even under f/11, the bokeh is still very good in outdoor photographing since it has a very short distance to the object (I guess it is less than 0.5 meter).

I also tested its focal 28mm, the IQ at f/2.8 is acceptable to me, and sharp enough at f/4, but very sharp at f/5.6. However, the bokeh is bad due to the closest distance is 1.5 meters.

I would like to recommend this lens strongly if the price is around &100, but it might be worth to have it as a collection if the condition is mint and the price is under $200.

Good luck!!


Registered: September, 2010
Location: MD
Posts: 942
Lens Review Date: December 7, 2012 I can recommend this lens: Yes | Price: None indicated | Rating: 8 

Pros: value, push-pull zoom w/ fixed focus; well-built; macro
Cons: zoom creep
Sharpness: 9    Aberrations: 9    Bokeh: 9    Handling: 7    Value: 10   

This is a very nice, solid lens. The 28-105 range is better suited for full-frame, but it works fine as ~42-157mm on an APS-C. Sharpness is quite good, and is even better used at the (pseudo-)macro setting which goes to 1:5. It has a push-pull zoom with a constant focus, so that makes it helpful for video work on my K-x. Mine is a 77xxxxx Kobori-made with the A-setting, and the auto exposure is quite good. Mine does have the Ricoh-pin, but it is the rounded type, and there have been no problems getting it on/off my camera. There is some lens creep when pointed down. It took me a little practice to get use to the push-pull zoom and turn to focus. All in all a very nice lens with good color and sharpness across the frame. I probably could rate it a 9, but since it has been replaced by my (considerably more expensive) DA 18-135, I haven't used it much, and I've reflected that in the 8 rating.
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Registered: May, 2010
Location: 1hr north of PDX
Posts: 3,784
Lens Review Date: October 28, 2010 I can recommend this lens: Yes | Price: $60.00 | Rating: 8 

Pros: decently sharp, great contrast, versatile closeup, minimal CF
Cons: flare, zoom creep

After "thorough" tests against several other lenses, this is my favorite '1-touch' zoom. Other than flare (no worse than the others) and zoom creep (worse due to larger front element), it outperformed the others. Color and contrast are very good, focus can be discerned better than most in live view, and switching into 'macro' mode is effortless: just zoom to 105mm and keep focusing to about 2 feet from front element. Minimum focus at other focal lengths is about six feet. Color fringing in tough lighting was minimal in my tests, much better than most.

Notes that I've read indicate that Vivitars with serial number 77xxxx are of Kobori manufacture. I tried their 28-85 without 'A' setting, also very good but no better than this one. For overall image quality, shooting versatility and 'A' setting this one is my keeper.
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