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

Started May 18, 2014 | Discussions thread
BobORama Senior Member • Posts: 2,484
Re: Can Pentax make A Decent Lens? Ricoh have not fixed QC issues...


-- hide signature --

BTW. I'm not a hypochondriac; an optichondriac maybe! But it doesn't faze me, rather glass worries than health ones!

In the end, there is a proper way to test for centering.   Nobody has done that.   And to believe that one individual has some how cornered the market on decentered lenses is... unlikely.

In my original reply to the OP I accused him of having skewed the results by skeweing the optical axis of the lens so that the very shallow DoF at F/1.8 would cause the effect he saw.   But I backed off that and instead asked for the original photo.   So something like this:

With F/1.8 the DoF might be 10-15 feet, depicted in green in my exaggerated cartoon, so if you are not perfectly aimed normal to the walls, they will appear in focus on one side, and OOF on the other.

Also, when I see complaints about decentering, its ALWAY left to right.   Can you think of a mechanism where by the QC failure would result in a left / right differential in focus?   Of course not, decentering would likely not have any preference.   If anything you would see a top / bottom shift as gravity causes the front element to sag relative to the body of the lens / camera.

Or put another way, you can dismiss Occam's razor, but its cut through a lot of bull over the centuries.

 BobORama's gear list:BobORama's gear list
Pentax K-5 Pentax K-1 Sigma 10mm F2.8 EX DC HSM Diagonal Fisheye Pentax smc DA 18-55mm F3.5-5.6 AL WR Samyang 14mm F2.8 IF ED MC Aspherical +9 more
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow