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03-04-2019, 02:28 AM   #16
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QuoteOriginally posted by superdave Quote
Hi everyone, just wondering if you have checked if your lens is perfectly centered?

After a close look at my test shots, I noticed that the extreme left of the frame is noticeably softer than the right of the frame, on about 10% of the frame (right edge is very sharp).
It is visible from 11mm to 15mm and I need to close down to f/11 to have the same edge sharpness left/right.
Is your left/right of the frame equally sharp?

I still have two days to exchange the lens, but I would like to know of others copies are perfectly fine.

Thanks!

photo: left side inverted next to right side inverted.
Until now I didn't check the lens this way.

I'd support clackers' with his suggestion. Since there can be many influences when shooting, I'd like to add a little bit and do it the following way:
  1. Search a soccer playfield, a sports hall or something similar. These locations offer nice lines and grass field or wall ahead. Best choice: shoot in a fully static scenery.
  2. Set the camera to electronic shutter, use the self timer (which also disables shake reduction).
  3. Set the lens to 11mm and f/2.8
  4. Shoot from a tripod following a line along the optical axis with fixed focus point, grass field or wall ahead. Use an appropriate live view grid to align along the line.
  5. Focus the center manually precisely on a subject along the line.
  6. Repeat the shot with camera head downwards.
  7. Compare the shots after you have turned the second one by 180.
  8. If both shots show the same or nearly same sharpness (pixel peep) in all areas the lens shouldn't be decentered.



Last edited by acoufap; 03-04-2019 at 02:33 AM.
03-04-2019, 05:20 AM   #17
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QuoteOriginally posted by acoufap Quote
Until now I didn't check the lens this way.

I'd support clackers' with his suggestion. Since there can be many influences when shooting, I'd like to add a little bit and do it the following way:
  1. Search a soccer playfield, a sports hall or something similar. These locations offer nice lines and grass field or wall ahead. Best choice: shoot in a fully static scenery.
  2. Set the camera to electronic shutter, use the self timer (which also disables shake reduction).
  3. Set the lens to 11mm and f/2.8
  4. Shoot from a tripod following a line along the optical axis with fixed focus point, grass field or wall ahead. Use an appropriate live view grid to align along the line.
  5. Focus the center manually precisely on a subject along the line.
  6. Repeat the shot with camera head downwards.
  7. Compare the shots after you have turned the second one by 180.
  8. If both shots show the same or nearly same sharpness (pixel peep) in all areas the lens shouldn't be decentered.
Thanks everyone, I already tried the suggestion of clackers, shooting the same scene with the camera upside-down to be sure that the left edge softness is not because of the scene, and it is not because of the scene as the softness goes to the right side.

I also tried the test of focusing on an object at infinity, using the clamp to lock focus (very nice feature) and shooting the object in each corner. The two left corners are less sharp that the two right corners.

I took many shoots during the weekend and I am always a little disapointed to see the left edge (and also the left ground corner) blurry while the right edge is perfectly fine, so I will return the lens tomorrow for exchange, and cross my fingers to get a perfectly aligned lens next time, I suppose there are good copies.
03-04-2019, 05:29 AM - 1 Like   #18
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QuoteOriginally posted by superdave Quote
Thanks everyone, I already tried the suggestion of clackers, shooting the same scene with the camera upside-down to be sure that the left edge softness is not because of the scene, and it is not because of the scene as the softness goes to the right side.

I also tried the test of focusing on an object at infinity, using the clamp to lock focus (very nice feature) and shooting the object in each corner. The two left corners are less sharp that the two right corners.

I took many shoots during the weekend and I am always a little disapointed to see the left edge (and also the left ground corner) blurry while the right edge is perfectly fine, so I will return the lens tomorrow for exchange, and cross my fingers to get a perfectly aligned lens next time, I suppose there are good copies.
Hope you'll get a new flawless copy soon. Good luck!
03-05-2019, 06:17 PM   #19
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Cloudy day at southern Maryland.

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03-06-2019, 12:34 PM   #20
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KP • DA*11-18 • ISO100 • f/22 • 20s
03-10-2019, 10:30 AM - 2 Likes   #21
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QuoteOriginally posted by acoufap Quote
Hope you'll get a new flawless copy soon. Good luck!
Got my new copy and both sides look equally sharp/soft now
Left side is a little sharper than my first copy, but right side is a little softer, probably a side effect of the decentring which make the right side sharper than normal on my first copy...
So edges are not as perfect as I thinked in the first place, especially at 11mm and 12mm.
I would say the lens is a little sharper than 12-24mm, but not that much when closed down. It has a little less CA, and contrast is a little better too.
All in all, it perform better than 12-24, and build quality is far superior in all points!
One interesting thing is that 12mm on the 11-18 have a larger field of view than on 12-24.

I also tested sunstars, but I am a little disapointed as you have to close to f/16 or f/22 to really see them (bloody rounded aperture blades...).

Here are a few DNG for those who want to see how the lens perform: WeTransfer
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04-26-2019, 04:18 PM   #22
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Had a chance to shoot something else besides brick walls.
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Last edited by Ex Finn.; 04-26-2019 at 05:01 PM.
04-26-2019, 04:43 PM   #23
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Back at Udvar-Haze.

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04-26-2019, 06:01 PM - 2 Likes   #24
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I used the DA*11-18 every day in March. Album HERE. I haven't formally tested my copy for centring, but I haven't seen any major cause for concern.

Some highlights of the month:











05-13-2019, 01:44 PM - 1 Like   #25
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Two from last vacation. Great lens.



06-10-2019, 01:42 PM - 1 Like   #26
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Not much traffic here ...









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