Weird OOF spot in (all?) Irix 15 including dpreview's

Started Dec 14, 2018 | User reviews thread
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alberto_b
alberto_b Regular Member • Posts: 154
Weird OOF spot in (all?) Irix 15 including dpreview's

I tried 2 copies of Irix 15 mm and both have the same defect, found also in dpreview gallery: a spot of OOF randomly appearing at center-left or center-right of the image, inside the APS-C area. You can see it clearly if you use it wide open on the infinity mark. The spots are rear focused, usually you need to manual focus to around the 3 m mark to get them sharp.

Probably it's a mechanical bug in the inner elements movement, since the spot locaton vary if you get the infinity mark turning the ring CW or CCW.

Since 3 samples on 3 tested are defective the same way, I think it's statistically relevant -that's why I can't recommend this lens, although optical design is very good IMHO.

Examples:

From dpreview gallery at f2.8, center-left part of the image at 100%, IQ growing from right to left

From dpreview gallery at f2.4, center-right part of the image at 100%, IQ growing from left to right

My first copy, the good and the bad, full res APS-C frame (Pentax K70)

My second 15 mm copy, two 100% crops of same frame focused to infinity rotating ring CCW - no good at right

My second 15 mm copy, focused to infinity rotating ring CW - very bad at left

 alberto_b's gear list:alberto_b's gear list
Panasonic Lumix DMC-LX7 Pentax K-70 Pentax smc FA 50mm F1.4 Pentax smc DA 12-24mm F4.0 ED AL (IF) Pentax smc DA 18-55mm F3.5-5.6 ED AL II (IF) +10 more
Irix 15mm F2.4
Wideangle prime lens • Canon EF, Nikon F (FX), Pentax KAF3
Announced: Mar 16, 2016
alberto_b's score
2.0
Average community score
3.2
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