Easy check decentered lens

Started Mar 7, 2022 | Questions
Gjdevr New Member • Posts: 4
Easy check decentered lens
1

Is it ok to check decentering easily by take a pic of a brick wall at 50 feet/15 meters and then compare in your camera the corners, plus check differences in curves?

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jrkliny
jrkliny Veteran Member • Posts: 4,931
Re: Easy check decentered lens
4

The more typical way is to shoot the brick wall, then rotate the camera 180 degrees and shoot again.  If one side is soft and the soft side rotates, the lens is decentered.

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Guy Parsons
Guy Parsons Forum Pro • Posts: 41,011
Re: Easy check decentered lens
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Gjdevr wrote:

Is it ok to check decentering easily by take a pic of a brick wall at 50 feet/15 meters and then compare in your camera the corners, plus check differences in curves?

That's the usual way, but have a read of this https://www.lensrentals.com/blog/2012/05/testing-for-a-decentered-lens-an-old-technique-gets-a-makeover/

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Jessica M Regular Member • Posts: 296
Re: Easy check decentered lens

Guy Parsons wrote:

Gjdevr wrote:

Is it ok to check decentering easily by take a pic of a brick wall at 50 feet/15 meters and then compare in your camera the corners, plus check differences in curves?

That's the usual way, but have a read of this https://www.lensrentals.com/blog/2012/05/testing-for-a-decentered-lens-an-old-technique-gets-a-makeover/

Thanks for sharing that link.  Decentering is more complicated that I originally thought.

Jessica M Regular Member • Posts: 296
Re: Easy check decentered lens

Gjdevr wrote:

Is it ok to check decentering easily by take a pic of a brick wall at 50 feet/15 meters and then compare in your camera the corners, plus check differences in curves?

Not just the corners.  I had a decentered lens which produced a blurry zone in the 11 o'clock area.  It was unusable for group portraits as certain people were blurry despite adjacent persons being quite sharp.

jrkliny
jrkliny Veteran Member • Posts: 4,931
Re: Easy check decentered lens

When you read some of the complaints about lens, camera and gear performance it is easy to become discouraged.  I guess I have just been lucky.  Over the past ten years or so, my wife and I have had a total of about 1 dozen Canon lenses.  I have never had a lens that was decentered, had any other major issue or even required all but minimal microtuning for the autofocus.

I did have the focusing motor die on a cheapy lens I got with my first Canon Rebel.  I have scratched a couple of lenses when they banged on rocks while hiking in the mountains.  My one repair was on a Canon L lens, the 100-400 bazooka when the main seal broke.

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