| Author: | | Inactive Account Registered: September, 2011 Posts: 6
4 users found this helpful
| | Review Date: September 27, 2011 | Recommended | Price: $100.00
| Rating: 9 |
| Pros: | sharpness, size, price, multi-coated | | Cons: | contrast, off-brand | | Sharpness: 10
Aberrations: 9
Bokeh: 9
Handling: 9
Value: 10
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Interesting that no one has reviewed this lens yet.
Very sharp little lens.
Cosina had manufactured lenses for other makers in the past. Optically, according to some users, this Cosina 24/2.8 was also branded Carl Zeiss Jena II 24mm/f2.8. It is multi-coated, although not as prestigious as Pentax SMC in performance. I've had an A24 2.8, which gives better contrast.
Some specs can be found here . I've seen this lens available in M42, PK, and PKA mounts. I own a PK version myself.
Compared to my A24 2.8, I would say the sharpness is right up there but A24 gives a better coloring to my liking.
For the price paid, it's pretty good value overall.
| | | | | | | Senior Member Registered: December, 2009 Location: East Yorkshire Posts: 120
3 users found this helpful
| | Review Date: July 23, 2012 | Recommended | Price: None indicated
| Rating: 9 |
| Pros: | Sharpnes, good contrast, well built | | Cons: | Finish a bit delicate | | Sharpness: 9
Aberrations: 8
Bokeh: 9
Handling: 7
Value: 10
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Found this lens on e-bay late last year. Claimed to be brand new and certainly looked it. I was the only bidder.
I am really pleased with the performance of this lens. I purchased it to replace my sigma 24mm super-wide that has siezed up. It out performs the sigma on all counts. The lens is sharp at all apertures, and has good contrast. Not really a true macro lens, as close focus is a property of wide angle prime lenses, that said the shots taken with this lens at close focus have been excellent.
My two niggles with this lens are that the focus ring turns in the other direction to Pentax lenses and the paint finish is very soft and susceptible to scratching.
In the past Cosina has not had the best reputation. But I have heard that it was subcontracted to manufacture Nikon lenses in the past. Also the optics made for Cosina's Voightlander range are superb, so maybe we should not be surprised that they have made such a good lens.
Not sure when this lens was available in the shops, but if you can find one in good condition buy it, you will not regret it.
| | | | | Veteran Member Registered: August, 2015 Location: Toulon, South of France Posts: 357
3 users found this helpful
| | Review Date: September 15, 2015 | Recommended | Price: $13.00
| Rating: 10 |
| Pros: | Punchy colors, close focusing, flash-friendly, contrast, value, KA | | Cons: | build, far focus, CA, distortion | | Sharpness: 10
Aberrations: 7
Bokeh: 9
Handling: 10
Value: 10
Camera Used: K200D
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I've tested deeply that lens I got cheap (10 euro) for parts only because a plastic ring in the aperture lever mechanism was out of normal place, good deal...
The close-to-mint copy I own :
 Cosina 24mm f2.8 mc macro 1:5 P/K-A Japan by Bruno Polleri, sur Flickr
The big positive point about this lens is its fantastic color and contrast you get natively in RAW files, you don't need to post-prod this, only maybe low a bit saturation or change your camera settings.
It is light, compact, very fine close focusing (19 cm min focus range) and gives very nice shots using the cheapest flash you have, your camera internal flash.
But it's not a perfect lens, more lateral CA than on my zooms and distortion, nothing horrible but if you want perfect photos, you will have to correct it from RAW files : with LR, you just need to click on "suppress lateral chromatic aberations", this works perfectly and then, in the "manual" tab, set distorsion to +5/+6 and you're done.
The other small cons is about the build, amongst my 3 primes (Chinon, Takumar and this one) it is the lightest cheap build, many plastic parts, filter thread is plastic and that's not very nice.
I've not yet deeply tested its bokeh so I can't rate it, will do later.
Overall, it is a very good lens, with the A position and A contact, compact and easy to use, at 2.8 softness is so tiny that you'll love to use it in low light conditions. It is extremly sharp at close range, a bit harder to focus long range mainly because it's a 24mm but still sharp as much as your sensor can be.
A test shot, very roughly taken, just to show how punchy is color and contrast, this photo is a direct RAW export to flickr, untouched :
 Cosina 24mm 2.8 MC Macro 1:5 test shot 2 by Bruno Polleri, sur Flickr
2 others at close focusing using internal flash :
 OMG 25 years ago... by Bruno Polleri, sur Flickr
 My oldest tool ever ! by Bruno Polleri, sur Flickr
*****
Here are some new bokeh test shots, not fantastic subjects, it's a cloudy day, I'll try to see how bokeh looks like with city lights in background later.
Shots below were taken with no filter and no hood.
Wide open (2.8) shot close focusing :
Purple and red by Bruno Polleri, sur Flickr
Stopped at 4.5 :
White flower by Bruno Polleri, sur Flickr
Wide open evening bokeh :
Evening bokeh by Bruno Polleri, sur Flickr
As you will notice, it's almost impossible to know which one was taken wide open, so I'll put a 10 on sharpness, and a 9 to bokeh even if 24mm is not the best focal for bokehs, because it is very smooth, 5 blades apertures seem often better than 6 blades for bokeh. Also before and beyond focus have a very close aspect.
I'll recommand it for its all situations capabilities and wide-open sharpness !
If you can find one in nice condition below 100$ don't hesitate to get it, I had mine very cheap because it was sold for parts and I've been very lucky in this gambling, it is the sharpest wide-open lens I have so it is very fast even at 100/200 iso.  And it is the more vibrant colors of all my lens atm. | | | | | Senior Member Registered: July, 2009 Location: London Posts: 212
1 user found this helpful
| | Review Date: December 16, 2016 | Recommended | Price: $45.00
| Rating: 9 |
| Pros: | Sharpness, CA, build | | Cons: | Distprtion | | Sharpness: 9
Aberrations: 7
Bokeh: 8
Handling: 9
Value: 10
Camera Used: Pentax K-S2
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The lens is well made metal with a few plastic parts. Even though 30 odd years old still works smoothly. Bad parts first. Distortion, towards the edges there is bending of the plane, though this is hard to measure only doing a brick wall test. So maybe not for architects, In normal everyday shooting expect it would not be noticed. However, this does not carry over to the sharpness or CA which are very good. Mine is a Vivitar brand variant with the 'A' pin, I have seen other brands, the focus grip is quite different, not cross hatched, but large indents for fingers. It can focus down to 20cm, the aperture blades give consistent exposure when shooting the same scene at different f numbers. On a APC cannot see any vignetting, obviously can't say for FF, for which it was made.
| | | | | | | New Member Registered: October, 2016 Posts: 2 | | Review Date: April 3, 2017 | Recommended | Price: $66.00
| Rating: 9 |
| Pros: | Small, sharp, well built, very good focal range | | Cons: | Some distortion | | Sharpness: 9
Aberrations: 8
Bokeh: 9
Handling: 10
Value: 10
Camera Used: K20D
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A nice treasure of lens. Been quite underestimated, probably because not a native Pentax lens (mine is branded Exakta), and not quite popular. My copy is close to new, very well built. The 'macro' option is very good, although not a real macro, but a close focus. I need to set exposure compensation on it (+0.3-0.7), as the K20D underexposes; I rarely shoot at something different than f4, at this aperture the lens perform really well. The 24mm on my cropped K20D sensor gives an FF equivalent of 36mm, which makes the lens a real walkaround classic.
 | | | | | Veteran Member Registered: July, 2014 Location: Nagoya Posts: 577 | | Review Date: May 17, 2017 | Recommended | Price: $50.00
| Rating: 9 |
| Pros: | Sharpness, colours, solid build | | Cons: | Some CA and distortion, but nothing unusual | |
I have the Miranda branded version with the KA mount.
As other reviewers have noted, this is a satisfyingly good 24mm. Overall image sharpness and colour is good, CA and distortion are no worse than any other wide angle, and the close focus function gives surprisingly good bokeh if you're willing to shove your camera right up against the subject.
Build quality is pretty good - not quite as smooth as some older lenses but everything it satisfyingly weighty and metallic. But not weighty as in too heavy - the sensible f2.8 aperture means that this lens won't pull your head off if you try to sling your camera round your neck. Maybe it's just me, but the 24mm f1.4s that have been appearing recently seem like a pretty weird idea.
If you're looking for the 24mm focal length, and not wanting one of the new monster lenses, then this Cosina, in whichever of its many forms, will not disappoint.
| | | | | New Member Registered: March, 2016 Posts: 2 | | Review Date: November 28, 2017 | Recommended | Price: $40.00
| Rating: 10 |
| Pros: | All except... | | Cons: | Plastic aperture ring. No af? | | Sharpness: 10
Aberrations: 9
Bokeh: 9
Handling: 10
Value: 10
Camera Used: K3II
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This lens is amazing from the begining to the end. The plastic aperture ring is the only thing that makes it not a perfect lens.
Is very sharp at 2.8 and super sharp at 5.6 but you can also shoot at f22!! being the image pretty good.
Contrast is ok but microcontrast at 2.8 is a bit soft, but only a bit.
Its not hard to focus because the depth of field, even at 2.8, in almost situations is enoug to get the pic in focus. (Not like with my old and sold takumar 135mm f2.5)
It doesnt create too much distorsion and deals very well with the aberrations.
Its nor the lightest nor the smallest but its not a monster like all the new 1.2 or some another new stuff.
For me is a perfect low cost prime combo with the Da 50mm 1.8 and the kenko x1.5.
24mm (35mm FF eq.)
50mm (75mm FF eq.)
50mm + x1.5 Kenko ( x1.4 real) 70mm (105 FF eq.)
 | | | | | New Member Registered: January, 2018 Location: Paris Posts: 8 | | Review Date: March 26, 2018 | Recommended | Price: $90.00
| Rating: 8 |
| Pros: | IQ, Neutral colors , close focus at 2,8 | | Cons: | None at this value | | Sharpness: 8
Aberrations: 8
Bokeh: 8
Handling: 10
Value: 10
Camera Used: K1
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Mine is exakta branded.mint copy .
This is a good little Lens
Very Sharp at 2,8 at close focus
2,8 usable (at least in the center area)
Very Sharp F4 and F8 on the whole frame
F5,6 and F11 are useless to improve iq among the frame it seems
Few ac
Build is really ok , not a PENTAX k but satisfying
A very good small 24mm and ok on K1 full frame. Maybe even better on apsc
I recommend this Lens
The only cons comparing to my zoom fa 20-35 is the less attractive contrast and color rendering wich is less warm but Maybe more natural
| | | | | New Member Registered: June, 2017 Posts: 15 | | Review Date: October 26, 2019 | Recommended | Price: $10.00
| Rating: N/A |
| Pros: | good on film - surprisingly good as a "standard" lens with close focus capaility on micro 4/3 bodies | | Cons: | none at the price | | Sharpness: 8
Aberrations: 8
Bokeh: 7
Handling: 9
Value: 10
Camera Used: P30 film; Lumix G5 for M4/3
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24mm lenses are hard to come by - and this has to be the bargain one to hunt down.
Mine is good on 35mm film - with little IQ problem seen on 7x5 prints. Especially - the colour rendition is very good. I have a sigma 24mm F2.8 and I think this is the better of the pair with lower distortion.
Used close up it is excellent - not a true macro - but very good for close ups - indeed it seems to be optimised for closer work rather than infinity focus.
+++++++++
UNEXPECTED BONUS - On Micro 4/3 with a 2 x crop factor and a telephoto 52mm thread long lens hood in place to reduce the chance of internal reflections it works very well as a "standard" almost macro / close focus lens. Focus is smooth and at F2.8 the manual focus is easy with the mirrorless viewfinders. Cropping out the edges solves the "soft corner" problem reported for full-frame 35mm.
This creates a close-focus "standard lens" that is unavailable at any reasonable price in native m4/3 mounts. Check out the price of the LUMIX G Macro 30mm f/2.8 Asph. as competition !
Long lens hoods are near necessitiies when adapting full frame lenses to Micro 4/3 as 50% of the full-frame lens image is "unused" - just creating light that can scatter internally dropping contrast and colour. I use those three-position rubber ones by choice as they extend a long way foreward when folded out and give great lens protection as well as shading.
| | | | | New Member Registered: November, 2013 Posts: 14 | | Review Date: September 20, 2022 | Recommended | Price: $45.00
| Rating: 9 |
| Pros: | very sharp lens in the center and midframe 75LP/mm | | Cons: | some few visible CAs at the border and in the corners | | Sharpness: 9
Aberrations: 8
Bokeh: 7
Handling: 8
Value: 10
Camera Used: pentax k-5 k-x k200 k-s1 Fuji x-t100 x-e1
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I've got both identical versions of Cosina and EXAKTA . Especially for close ups very fine lenses (not 1:1 "MACRO" as indicated)
The Cosina/EXAKTA lenses 2.8/28 are a few better CA corrected in the corners, obviously, but if ou stop them down to f 8-11 the weak sharpness of the extreme border and corners will disappear nearly totally (no more / not visible on 20 x 30 cm = 8" x 12" inches)
O/+ not perfect corner sharpness and CAs correction with wide open aperture = 7 points 
+ corner sharpness and CAs stopped down the aperture to f 8 - 11 = 8 points 
+++ center sharpness wide open and stopped down = 10 points
PS: for big magnifications corner CAs must be corrected by PhSh.
averidge 8.5 points
in comparison with 7artisans 1.8/25 the a.m.COSINA/EXAKTA lenses have no visible distorsion, it is trong for close ups of 7artisans.
BUT
CAs correction of the 7artisans lens is much more better over the full aperture range and in the extreme corners, but the sharpness of approx. 2 % of the image in the extreme corners is not sufficient, even with f 16. Therefore 7artisans for portraits / flowers etc., but COSINA/EXAKTA for landscapes architecture etc..
75 LP/mm = 150 black and white lines per mm is a semi-professional value ! | | | | | Senior Member Registered: June, 2020 Location: Guangdong Posts: 180 | | Review Date: February 6, 2023 | Recommended | Price: $65.00
| Rating: 9 |
| Pros: | close-up ability, color, PKA, weight & size, good value for money | | Cons: | Vignetting on FF, corner distortion | | Sharpness: 9
Aberrations: 8
Bokeh: 9
Handling: 9
Value: 10
Camera Used: K-50, Lumix S5
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I bought this lens at the Yahoo auction for 8700 JPY (approx. $ 65). Overall, I think it is of great value for the price! Though the glasses and body are both in good condition, my copy has a rather stiffy focus ring... But, better than no damping, right?
With PK-A mount supported, I won't get fussy about the metering. That's great.
The "Macro" function of this lens is really really helpful and that's the key reason I would love to purchase this lens! From food to plants, you get fantastic results doing close-up shots even at wide open! I strongly recommend this lens as a daily city-walk lens.
Sample photos I took with this lens on K-50 and Lumix S5 👇
https://www.pentaxforums.com/forums/122-lens-clubs/372480-24mm-club-any-all-...ml#post5695616
You can see obvious vignetting on the Lumix S5 (FF mode, both are taken wide open). However, someone may see a vintage atmosphere in that, haha. The corner distortion is quite notable btw.
I haven't got the chance to test its glare&ghost-resist ability to see how its MC (multi-coated) feature works. I may post results concerning that later.
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