Re: Is there a quick and easy test for the 16-50 decentering problem?
On Apr 9, 2010, at 6:50 PM, David Parsons wrote: Are you planning on taking lots of pictures of brick walls? No. But it would be handy to be able to test it at the camera shop rather than after driving the thirty miles home. I would try shooting with the lens for a while under normal conditions and investigate if you see a consistent problem. There is that too. -- Larry Colen l...@red4est.com sent from i4est -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Is there a quick and easy test for the 16-50 decentering problem?
Yes, do that as you tell. But don't forget to try several distances among close-to-medium focus. The one I had on test was excellent around 60-70mm, awful around 1-1.5m and then good beyond that distance. Dario - Original Message - From: Larry Colen l...@red4est.com To: Pentax-Discuss Mail List pdml@pdml.net Sent: Saturday, April 10, 2010 1:11 AM Subject: Is there a quick and easy test for the 16-50 decentering problem? Would it be something like take a picture of a flat surface (brick wall) and look for one corner being out of focus? -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Is there a quick and easy test for the 16-50 decentering problem?
Would it be something like take a picture of a flat surface (brick wall) and look for one corner being out of focus? -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Is there a quick and easy test for the 16-50 decentering problem?
Are you planning on taking lots of pictures of brick walls? I would try shooting with the lens for a while under normal conditions and investigate if you see a consistent problem. On Fri, Apr 9, 2010 at 7:11 PM, Larry Colen l...@red4est.com wrote: Would it be something like take a picture of a flat surface (brick wall) and look for one corner being out of focus? -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Aloha Photographer Photoblog http://alohaphotog.blogspot.com/ -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Is there a quick and easy test for the 16-50 decentering problem?
With the 16-50, what you're looking for is a focus field that is not flat.. A brick wall will work. But shoot off a tripod and make sure the camera is square to the wall. Expose at f2.8. If the lens has the misalignment problem that plagued some copies of the 16-50, one edge of the frame will be out of focus when the other edge is in focus. It's pretty easy to detect. From what I've heard, the lenses are really way off or not at all. My first copy was defective, and I noticed it before testing. With a brick wall test, it was completely obvious. Paul On Apr 9, 2010, at 7:11 PM, Larry Colen wrote: Would it be something like take a picture of a flat surface (brick wall) and look for one corner being out of focus? -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
