Dropped Lens- How to check?

tokyoscape · 02-16-2020, 07:36 PM

I would do a decentered test too. Lense gets bumped and or dropped can cause lens elements to misalignment / decentered.

How to Check Your Lens for Decentering - Articles and Tips | PentaxForums.com

**aslyfox** · 02-16-2020, 08:05 PM

I dropped my D FA 100mm F2.8 Macro ( no WR ) today

amazingly, I just yelled " shoot ", when it happened

[ very lucky since I was at the Topeka Zoo and there were families with kids ]

it appears to have survived

I certainly hope so.

PentaPrime · 02-16-2020, 10:24 PM

Originally posted by tokyoscape

I would do a decentered test too. Lense gets bumped and or dropped can cause lens elements to misalignment / decentered.

How to Check Your Lens for Decentering - Articles and Tips | PentaxForums.com

I'll try the test tomorrow but for now, let's assume it's damaged. What can be done to repair it?

tokyoscape · 02-17-2020, 12:56 AM

Originally posted by PentaPrime

I'll try the test tomorrow but for now, let's assume it's damaged. What can be done to repair it?

If it were decented by the impact, I guess the only way to fix is send it in for professional service.
The cap didn't fly off upon the impact, right? I hope the test will confirm that your lens is not decented.Goodluck

Sandy Hancock · 02-17-2020, 02:03 AM

Shoot a series of images at a brick wall at a variety of focal lengths, with the camera level and the sensor parallel to the wall.
If the images look OK, relax and enjoy your lens.

Don't bother checking the filter threads

PentaPrime · 02-17-2020, 05:44 PM

Top left corner images do appear to be blurrier than the other corners, however it might have been this way before (I got this lens about six weeks ago, but I hadn't done a baseline test yet). I'll never know, I suppose. Also on further inspection I can't find an issue with the aperture mechanism, except that from 2.8, to 3.2, to 3.5, I don't find that it seems to get much darker. At f/4 and above it goes noticeably, incrementally darker with each stop. But perhaps from 2.8 to 3.5 it is just not very noticeable. I was testing this under natural light with constant shutter speed and ISO, but I will try with a controlled artificial light.

02-16-2020, 08:05 PM	#17
aslyfox Seeker of Knowledge Join Date: Aug 2016 Location: Topeka, Kansas Photos: Gallery \| Albums Posts: 24,583	I dropped my D FA 100mm F2.8 Macro ( no WR ) today amazingly, I just yelled " shoot ", when it happened [ very lucky since I was at the Topeka Zoo and there were families with kids ] it appears to have survived I certainly hope so. Last edited by aslyfox; 02-17-2020 at 03:05 AM.

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02-16-2020, 07:36 PM	#16
tokyoscape Inactive Account Join Date: Oct 2018 Location: Tokyo Photos: Gallery Posts: 1,256	I would do a decentered test too. Lense gets bumped and or dropped can cause lens elements to misalignment / decentered. How to Check Your Lens for Decentering - Articles and Tips \| PentaxForums.com

02-16-2020, 10:24 PM	#18
PentaPrime Forum Member Join Date: Jun 2018 Location: Calgary Posts: 65	Originally posted by tokyoscape I would do a decentered test too. Lense gets bumped and or dropped can cause lens elements to misalignment / decentered. How to Check Your Lens for Decentering - Articles and Tips \| PentaxForums.com I'll try the test tomorrow but for now, let's assume it's damaged. What can be done to repair it?

02-17-2020, 12:56 AM	#19
tokyoscape Inactive Account Join Date: Oct 2018 Location: Tokyo Photos: Gallery Posts: 1,256	Originally posted by PentaPrime I'll try the test tomorrow but for now, let's assume it's damaged. What can be done to repair it? If it were decented by the impact, I guess the only way to fix is send it in for professional service. The cap didn't fly off upon the impact, right? I hope the test will confirm that your lens is not decented.Goodluck

02-17-2020, 02:03 AM	#20
Sandy Hancock Moderator Site Supporter Join Date: Feb 2012 Location: Adelaide Hills, South Australia Photos: Gallery \| Albums Posts: 11,275	Shoot a series of images at a brick wall at a variety of focal lengths, with the camera level and the sensor parallel to the wall. If the images look OK, relax and enjoy your lens. Don't bother checking the filter threads

02-17-2020, 05:44 PM	#21
PentaPrime Forum Member Join Date: Jun 2018 Location: Calgary Posts: 65	Top left corner images do appear to be blurrier than the other corners, however it might have been this way before (I got this lens about six weeks ago, but I hadn't done a baseline test yet). I'll never know, I suppose. Also on further inspection I can't find an issue with the aperture mechanism, except that from 2.8, to 3.2, to 3.5, I don't find that it seems to get much darker. At f/4 and above it goes noticeably, incrementally darker with each stop. But perhaps from 2.8 to 3.5 it is just not very noticeable. I was testing this under natural light with constant shutter speed and ISO, but I will try with a controlled artificial light.