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Cosina MC Cosinon-W 28mm F2.8

Reviews Views Date of last review
4 32,233 Fri January 27, 2023
Recommended By Average Price Average User Rating
100% of reviewers $20.58 8.50
Cosina MC Cosinon-W 28mm F2.8

Manual prime lens. Multicoated.
Focal length: 28mm
Max length: 37,6mm + mount
Max diameter: 62,5mm
Weight: ~140g
Aperture: f/2.8-f/22, 5 blades
Min. focus distance: ~0.25m
Filter diameter: 49mm
All metal construction.
Mount Type: Pentax K
Price History:

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New Member

Registered: June, 2017
Posts: 8
Review Date: January 27, 2023 Recommended | Price: $17.33 | Rating: 9 

Pros: Sharp F5.6 to 11 - as good as any, colour
Cons: edges and contrast sofetr F2.8- 4
Sharpness: 8    Aberrations: 8    Bokeh: 4    Handling: 9    Value: 9    Camera Used: APS and 35mm film   

This Cosina is available as branded as a VIVITAR - with a serial number starting 9......

It is small, mechanically good, and has a 5-blade aperture.

As with all the "amateur" wide-angles of its day the lack of aspheric and floating elements means there is some CA in the corners when the aperture is wide open and that very close focusing is limited - while the corners are softer with lower contrast below f5.6.

By F5.6 it is as good as any wide that I have tried from the 35mm film era. I especially like the colour rendition of greens while flare control is surprisingly good. It also takes a polarising filter without vignetting. It is as good as my SMC Pentax.

My usual caveat for film-era wide angles used in the digital era stands -
  • The rear element of most wideangle designs is very close to the sensor so any optical problems get amplified.
  • This is especially true of haze from vaporised lubricants from the aperture mechanics and focusing helicoid.
  • Near every one of my wides has seen a big jump in image quality on unscrewing the rear elements and giving them a clean with 100% ethanol to dissolve oily residue.
    • this is usually a much easier repair task than trying to get into the front element region.
New >24MP digital era wides are large, heavy and very expensive - for all those floating and aspheric elements - all of which makes them better performers at wide apertures, for sure. However, given how easy it is to focus a manual wide-angle at f5.6 - f8, these lenses are a bargain in comparison. For example - it is Cosina who makes the new Voigtlander Color-Skopar 28mm F2.8 launched 2021 that costs $600. How much added value is that over my 2023 buy at $17.33 USD (including postal costs).

On an APS crop digital these 28's become a sort of "40mm equivalent" lens - making them a great compact and affordable prime manual focus "standard lens".

Focus confirmation "aids" in APS DSLRs can be helpful with this lens - but I often have to fiind a high-contrast area to use as a target; which is much the same as with split-image and microprism focus aids in film cameras. I have no such trouble with telephotos as the subject tends to "snap" into place. On the other hand - with a 28mm you can just set f8 and "zone focus" !

This lens also makes a surprisingly good "standard lens" on micro 4/3. I use a telephoto size metal lens hood to cut back veiling flare from the internal reflections from the "redundant" 75% of the peripheral glass that is "cropped out" of the M4/3 sensor area - and this means you get good central resolution, colour and contrast even at f2.8. I find this a better experience, both in handling and in image quality than the new Chinese 25mm MFT lenses from the likes of Meike and 7-Artisans.
New Member

Registered: July, 2014
Posts: 2
Review Date: April 27, 2015 Recommended | Price: $20.00 | Rating: 9 

Pros: Very sharp
Cons: Focus ring a little stuck but usable
Sharpness: 9    Aberrations: 9    Bokeh: 9    Handling: 8    Value: 10    Camera Used: K-500   

Very good build quality.
Bought on ebay and still came with the original box and filter UV.


New Member

Registered: November, 2013
Posts: 13

1 user found this helpful
Review Date: April 5, 2014 Recommended | Price: $35.00 | Rating: 9 

Pros: very sharp lens
Cons: very few CA's in the corners wide open
Sharpness: 9    Aberrations: 8    Bokeh: 9    Handling: 9    Value: 10    Camera Used: kx-x,k-5,k200,sfx,mz10 etc   

even with a 5/7 tele-converter enormous sharp at f8.

suitable for cose-up photos, too

somewhat weak in the corners wide open, disappers when stopped down a few
Senior Member

Registered: June, 2009
Location: Finland, Kotka
Posts: 183

1 user found this helpful
Review Date: March 18, 2012 Recommended | Price: $10.00 | Rating: 7 

Pros: Quite fast
Cons: Not the sharpest lens
Sharpness: 7    Aberrations: 8    Handling: 8    Value: 8   

Not the sharpest 28mm but usefull for landscapes.
Good build quality.

Snow and Ice by LeGuillotine, on Flickr

This can't be so rare that I have to add lens to database and make the review too
Add Review of Cosina MC Cosinon-W 28mm F2.8

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