Can Pentax make A Decent Lens? Ricoh have not fixed QC issues...

Started 5 months ago | Discussions thread
Trevor G
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Re: Can Pentax make A Decent Lens? Ricoh have not fixed QC issues...
In reply to BobORama, 5 months ago

BobORama wrote:

Trevor G wrote:

Perhaps I have no idea what you are getting at, in which case I apologise in advance. Post the full image so we can get some context.

Oops - here it is (I'm so used to posting this image in the past I tend to think everyone knows it):

If you want a real test, shoot a completely flat surface perfectly perpendicular to the normal. Or better, shoot a star field wide open. Focus the center of the image perfectly. You will see various aberations, but they should be equal in magnitude as you get farther from the center. Any decentering will be apparent.

Here's the other, easy to see shot which shows the skew to the DOF:

Open at max size and scroll from one side to the other while watching the DOF shift as you scroll - it's closer one side than the other, and also a different depth from side to side.

Also if 19 of your 20 lenses have this issue, perhaps the issue is with the camera body.

Both sold.  It didn't matter - they all showed the same relative skew.

Do all of the lenes have a right - left focus shift?   And with a top to bottom shift?

It's not the camera.  Betcha. 

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Cheers
Trevor G
Silkypix tutorials at: http://photo.computerwyse.com

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