Pentax 15mm Limited problems

Started May 26, 2012 | Discussions thread
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HL53
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Pentax 15mm Limited problems
May 26, 2012

Everyone,

I own a Pentax K5 and a set of Limited lenses but I was missing a really good wide angle prime so I bought the 15mm Limited. However, I have been very disappointed with this lens as the edge performance is woeful. I compared it to an A900 Sony with a 25 year old Minolta 20mm f2.8 and was surprised at the result. The old Minolta was superior in every way but conventional wisdom would indicate that a modern wide angle with a modest f4 maximum aperture should have better edge definition than a 25 year old wide angle with a brighter maximum aperture.

I have attached a comparison and would ask users of the 15mm Limited if they find the edge performance poor or have I purchased a faulty copy. Please note that in the comparison both lenses are equal in the central 50% of the image and the disparity only occurs at the edged (around 15%) of the frame. I suspect field curvature is the culprit but it would be useful to get the experience of other users. Please note that I do not have this issue with any other limited lens.

Both cameras were set to 200iso and the results are consistent in both RAW and JPEG. The results are also consistent regardless of how the lenses were focused, i.e. manually, hyperfocal distance or AF.Any feedback would be appreciated.

Best regards, Howard

 HL53's gear list:HL53's gear list
Sony Alpha DSLR-A850 Nikon D800 Nikon AF-S Nikkor 28-70mm f/2.8 ED-IF Nikon AF Nikkor 85mm f/1.4D Olympus M.Zuiko Digital ED 9-18mm 1:4.0-5.6 +6 more
Pentax K-5
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