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08-05-2009, 12:48 AM   #1
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COSINA 50 mm f/2?

Someone could tell me if is a good len?
Some photo example?
Is it good about flare, etc.?
Is there a big difference with Pentax 50 mm f/1.7 (m or a)?
Resolution? Quality?

08-20-2009, 05:47 AM   #2
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Ciao Alex.

I have both a Cosina 50mm f/2 and a Pentax 50mm A f/1.7 both in superb codition. I have done tests in the past and was surprised at the good results from the Cosina.

The Cosina seems easier to get consistently sharp results. The Pentax seems to be less consistent with sharpness. Amazingly sharp at times and then the next shot, of the same subject at the same distance, nothing is in focus. This sometimes is true with the Cosina. More the camera's fault than the lenses.
Cosina made lenses for some big names.

I will do more tests and post a link to the images. It will be interesting to see the results.

I have analysed several test images taken outdoors, and the two lenses are very close in image quality. The Cosina is much better at very close distances. And has surprisingly good control of flare.

Last edited by sonny2962; 08-21-2009 at 05:55 AM.
08-25-2009, 11:40 AM   #3
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I too have a Cosina 50mm F2 bought together with a Cosina ct-1a ( never used ), seems cheap, without the ability to use middle diaphrams ( it doesn't have an intermediate step e.g. between 5.6 and 8 ) and i still don't have a Pentax digital body to try it out...

Could you please post a sample maybe at large aperture ( or crops, center borders and so... )?

Thank you.
09-13-2009, 10:15 AM   #4
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I have just bought a 50mm 1.7 A and well, the focus rings seems to rotate better.

Still i haven't received my new K20 so i can't say anything about image quality.

10-15-2009, 01:24 PM   #5
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Cosina f/2

Hi. Sorry for the delay, I have been on holiday and snowed under with other things. I will be posting a link to some comparison images.
10-15-2009, 01:54 PM   #6
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Comparison Images

Here is the link to the full size images, converted from raw using DXO Optics 5.3.4 same settings for sharpness etc.

I hope I got this right!!

Last edited by sonny2962; 10-15-2009 at 01:56 PM. Reason: wrong link
10-15-2009, 03:10 PM   #7
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Try this Link

That must have been the wrong one.

Try this.

Picasa Web Albums - Shaun - Cosina and Pe...
10-18-2009, 08:32 AM   #8
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Thank you for posting this, I don't see a great difference, both good lenses.

10-21-2009, 03:40 AM   #9
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Very True

You are completely correct. The Cosina seems to be very good image quality wise. Some respects it is even better. Such as lateral chromatic aberration and longitudinal aberration at shorter distances. It is a complete bargain.

I have one of my images on iStockphoto accepted and downloaded using this lens.

Young Woman Outdoors | Royalty Free Stock Photo Image |

Many thanks

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