[awscreo]

Thank you for sharing images. I definitely have something to compare to after I do the tests. Another thing I thought might be an issue - af. I'm guessing using a central point and recomposing might not work too well for this lens if focal plane is curved, maybe I need to move the focusing point to the object, or at least close to it. Also, need to check if lens is back/front focusing, maybe that can cause the blurry areas. Lots to thing about.

[tryphon4]

This pic is handheld, 15mm F/5.6:


The K-1 depth of field is so small that it is easy to get a front/back focus and even at 15mm you have to close the aperture to get enough DOF.

[Sandy Hancock]

Some hand held examples in the suspect shutter speed zone:

ISO 100, f/11 and 1/250. Pretty good from wall to wall I reckon.



Not razor sharp at 1/60 and off base ISO, but still acceptable and even across the frame.



I think your copy is de-centred, and needs servicing.

[awscreo]

Some hand held examples in the suspect shutter speed zone:

ISO 100, f/11 and 1/250. Pretty good from wall to wall I reckon.



Not razor sharp at 1/60 and off base ISO, but still acceptable and even across the frame.



I think your copy is de-centred, and needs servicing.

eh, second decentered copy in the row. I wonder how Adorama is storing lenses, possibly kicking them to the shipping bay? Or using it as building bricks for Zeiss Otus lenses? Just my luck I guess.

[Na Horuk]

Did you check the aperture blades? They can be a little asymmetrical when stopped beyond f12 (they don't form a perfect circle at small apertures on pretty much all modern lenses), but they should operate fairly smoothly. If tthere is a problem with the blades it could result in uneven DoF

[awscreo]

Question - do you guys shift the focus pointer to the object you want to focus on with 15-30 or focus with the central point and re-compose? I seem to have better results if I shift the focus pointer as close to the object as possible.. Dunno if it's the sign of decentering or its just how the lens suppose to work, maybe a curved focal plane?

---------- Post added 12-19-17 at 08:21 PM ----------

Did you check the aperture blades? They can be a little asymmetrical when stopped beyond f12 (they don't form a perfect circle at small apertures on pretty much all modern lenses), but they should operate fairly smoothly. If tthere is a problem with the blades it could result in uneven DoF

Blades seem fine to me

[Medex]

I do focus with central point and recompose.

[awscreo]

Just came back from a short trip, and unfortunately I'm still seeing the issue. Pics available below, I've even marked the blurred edge. Basically only one side can be sharp at the same time, either right or left. Usually left side is soft, if I try to focus on that side then right side goes out of focus. I'm guessing it's a second dud in the row? What you guys think? Center is consistently sharp, so i don't think it's motion blur. I've only posted few pics, but I have more that show pretty much the same effect. I didn't get a single image that I would say is evenly sharp across the frame..

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[Paul the Sunman]

Yes, it's on the wrong side of acceptable, especially for such an expensive lens. The worst case is 3195.

CA is pretty strong too, perhaps a little stronger than I'm used to seeing with this lens.

[Medex]

Just came back from a short trip, and unfortunately I'm still seeing the issue. Pics available below, I've even marked the blurred edge. Basically only one side can be sharp at the same time, either right or left. Usually left side is soft, if I try to focus on that side then right side goes out of focus. I'm guessing it's a second dud in the row? What you guys think? Center is consistently sharp, so i don't think it's motion blur. I've only posted few pics, but I have more that show pretty much the same effect. I didn't get a single image that I would say is evenly sharp across the frame..

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in my opinion, your lens has coma issue on the left side. TIM3195 and TIM3197 pictures perhaps show this. Look at small lights in those pictures, the form is like elongated semilunars. But those lights are not in perfect focus. The elongation of small dot like sources in the frame corners is always visible in super wide field of view lenses, the same thing you can observe using Samyang 14 mm, but here (TIM3195 and TIM3197 pictures) I suspect coma. If these pictures were taken at f8-11, then teh lens is really suspicious. The starry sky test is advisible.

[awscreo]

in my opinion, your lens has coma issue on the left side. TIM3195 and TIM3197 pictures perhaps show this. Look at small lights in those pictures, the form is like elongated semilunars. But those lights are not in perfect focus. The elongation of small dot like sources in the frame corners is always visible in super wide field of view lenses, the same thing you can observe using Samyang 14 mm, but here (TIM3195 and TIM3197 pictures) I suspect coma. If these pictures were taken at f8-11, then teh lens is really suspicious. The starry sky test is advisible.

Unfortunately skies are not clear these days. I'll give it a shot. At this point I'm trying to decide if I want to try to get a refund and shop in another store, or accept this as is and send it to Pentax for a fix-up. Is there any possibility lens is beyond repair? Or it's most likely just misaligned? So far I haven't had great experience with Precision Camera (Pentax side, I had great experience with them with my older Olympus body), but Tamron was able to completely fix my 70-200 decentered copy.

---------- Post added 12-21-17 at 12:47 PM ----------

I'm so upset with this experience... Thing is, I don't know anyone that has this lens in my area (or even the Tamron version of it) so I can go and compare with another copy directly, ruling out my own possible mistakes..

[awscreo]

This is a pretty much my final test I think, on tripod, perpendicular to the furthest wall, side walls are same distance from the camera. Left side is sharp, right side is soft, center is razor sharp. I couldn't achieve even focus on left/right sides without getting center softer, and even then it only makes the whole image softer.

_TIM3205.JPG - Google Drive

[awscreo]

Unfortunately lens is going back to the store for a refund. Thinking if I should try my luck with another store, or maybe settle with what I have for a while... What a shame

[Medex]

Unfortunately lens is going back to the store for a refund. Thinking if I should try my luck with another store, or maybe settle with what I have for a while... What a shame

I tried this evening interesting thing to test for decentering. At home I have a large day curtain with repeating fine texture. I noticed that the Pentax K-1 display shows moires on the whole area when good focus is achieved. If the lens is decentered, then moirs should be visible just in part of the dysplay. My lens shows moirs throughout whole area, at all angles simultaneously. You can see moirs on the dysplay even better than in the picture (link provided below) as colorfull areas.
But even at f8 I can see CA's on the frame edge. When sharpness is perfect in the center of the frame, it is not perfect (just good or very good) on the frame egde.
The tripod was positioned not so far from curtain, just about 1,5 meter. I did not see any sign of field curvature even at f2,8.
If you have at home a large day curtain with repeating fine texture, you can try to do this simple "test".

IMGP6269.JPG - Google Drive

[awscreo]

I tried this evening interesting thing to test for decentering. At home I have a large day curtain with repeating fine texture. I noticed that the Pentax K-1 display shows moires on the whole area when good focus is achieved. If the lens is decentered, then moirs should be visible just in part of the dysplay. My lens shows moirs throughout whole area, at all angles simultaneously. You can see moirs on the dysplay even better than in the picture (link provided below) as colorfull areas.
But even at f8 I can see CA's on the frame edge. When sharpness is perfect in the center of the frame, it is not perfect (just good or very good) on the frame egde.
The tripod was positioned not so far from curtain, just about 1,5 meter. I did not see any sign of field curvature even at f2,8.
If you have at home a large day curtain with repeating fine texture, you can try to do this simple "test".

IMGP6269.JPG - Google Drive

Thanks for sharing! It's an interesting test for sure, I don't think I have time to do it though, lens is heading back to Adorama tomorrow morning. I posted the last test image one post above, it was done on a tripod, focused perfectly on a wall ahead of me, perpendicular to it (i'm right in the middle of the room), yet sides of the image are not even, right side is much softer. I'm going to think what to do now - get another 15-30 from a different store, or settle with Rokinon (which is perfectly capable in general, I just wanted the flexibility of a zoom and WR), or maybe get something like Irix 15 or Laowa 12 or their new 15 2.

I've also thought of maybe selling my 28-105 as well, and possibly going an uwa prime (irix or laowa) + 24-70. Wouldn't be as flexible as having 15-30 + 28-105, but would probably save me some cash, and I always wanted to try a 24-70.