Cosina AF 28-105mm F2.8-3.8

Most will wonder which lens will end up as my 9th Lens. Yes, I am into my 9th len now. As I was browsing the photography forums and “looking” around, I saw a topic in the Buy/Sell folder of a local forum. The word “Cosina-Canon Mount” caught my eye. When I read on, this lens sounds really interesting, it’s a Cosina AF 28-105mm F2.8-3.8. I did a quick research on this lens and I found both positive and negative feedbacks about this lens. I decided to contact the seller and understand further. So it is a “push-pull zoom” lens – which means this is an old lens. The range from 28mm to 105mm also hinted that this lens is from the 2nd generation. (1st Generation 35mm is wide. 2nd Generation, 28mm is wide, the 3rd (current) Generation, 24mm is wide <18mm in EF-S>- anything wider is called “Ultra Wide Angle” or UWA Lens). However the apeture is interesting, F2.8 to 3.8, that means this lens is (supposed to be) a very fast lens even in today’s standard.

* picture:  Cosina AF 28-105mm F2.8-3.8.

A brief meeting was set up and I bought over the lens from the seller with little fuss, since I already expected more restoration work needs to be done. The lens elements was dusty from inside out, the rubber ring dirty and smudges all over the lens from the body to the glass. I sent the lens along with another used lens (which I am going to cover in the next article) to an expert for cleaning lenses, especially old and classic ones. Once that is completed, I set out to buy new filter, a new Canon 72mm front lens cap and a rear cap and further conditioned the rubber parts. Some screws was missing from the lens mount and I have them replaced too by the same expert. Now the lens looks like new. (will not be posting the pictures now – saving those for later articles) However, I found some really nice photos on the net for this lens as included in this article.

* picture:  Cosina AF 28-105mm F2.8-3.8. Nice piece of used glass of you ask me.

The construction of the lens is “so so”, but the apeture is sweet when wide open. Bokeh on portraits is creamy and smooth. At the telelphoto end, the lens performed inconsistently with AF working harder to focus at F3.8, but problem solved when the apeture narrows down to F7.1 and yes, now the lens is fast as claimed. It takes a bit of getting used to using this lens, once that is acheived, this is one great walkabout lens. On cropped bodies, the range increased to 45-168mm which is very acceptable for general walkabout shoot. Don’t try this lens on Macro though, it sucks. For a used lens that cost me less than SGD$100 including the restoration & cleaning charges plus the new filter and caps, I can’t really complain right?

* picture:  Cosina AF 28-105mm F2.8-3.8. This is how it looks like when it is NEW.
Some User Facts/ Information:
(If you are looking for the specs, please google yourself, it’s all over the internet.)
– Filter Size 72mm
– Lens Hood (No available information).
– Average lens for Infra-red Photography (IR), Hotspotting appears from F18 onwards.
– AF Runs on Micro Motor. 
– Push Pull Zoom
– Focal Range when used on bodies with smaller APS-C sensors – 45-168mm.
– Cosina’s “Canon Mount” is designed for use on Canon’s EOS Full Frame & Cropped Bodies (with corresponding increase x1.6 APS-C or x1.3 APS-H)

What I Like:
– Good walkabout range when used on my 500D & 350D-IR.
– Well priced (when New, even Better when USED).
– Push Pull Zoom is a Classic, every collector must have one of these lens.

What I Hate:
– Zoom Strays as there are no locking mechanism.
– Noisy Focusing.
– Push Pull Zoom design attracts dust into Lens Body and eventually inside the glass elements.
– No Distance Scale.

*Picture Source Internet.

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2 Responses to Cosina AF 28-105mm F2.8-3.8

  1. kevin voller says:

    i have just bought this lens with canon eos mount.
    love the lens but the micro motor drive belt has stretched with age and falls off
    rendering auto focus unuseable any idea where i can obtain a new one please.

  2. Hi Kevin,

    The drive belt is the very same that are used by other lenses like Vitacon, which is much easier to find than the Cosina. (Vitacon & Cosina was same company). The next nearest match is the older Sigmas, so maybe you can find a camera repair shop that carries a wide stock of old lenses might help.


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