thanks for lens reviews and a suggestion

Marc Sabatella · 07-11-2010, 09:29 PM

FWIW, the "Best in Class" on the DA*16-50 appears in last month's issue (the "Dive" special) in a roundup. And I note the review you mention does say the Sigma is better in certain areas, but sharpness is conspicuously missing from the list. Once more, I have no experience with or interest in defending the 16-50 - just observing that different people have different opinions. I can't imagine that I'd have anything more to add on this subject.

Last edited by Marc Sabatella; 07-11-2010 at 09:35 PM.

**rparmar** · 07-12-2010, 04:48 AM

Originally posted by Marc Sabatella

Once more, I have no experience with or interest in defending the 16-50 - just observing that different people have different opinions.

Of course that is true. I think my "meta point" is that not all opinions are created equal. They must be analysed and evaluated using hard data. And trust, built up over time.

bdery · 07-12-2010, 05:32 AM

MTF evaluates the capability of a lens to create a sharp and "instantaneous" transition between black and white. Nothing more. It is generally also used for general sharpness, but that's simplyfing.

You can beasure almost anything about a lens, honestly. All the aberrations (and I mean, ALL), disrotsion, contrast, sharpness can all be evaluated at the design stage, and verified after assembly.

Don't put too much weigth on MTF. It's an interesting measurement, but not at all the holy grail of lens quality evaluation.

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07-11-2010, 09:29 PM	#16
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	FWIW, the "Best in Class" on the DA16-50 appears in last month's issue (the "Dive" special) in a roundup. And I note the review you mention does say the Sigma is better in certain areas, but sharpness is conspicuously missing from the list. Once more, I have no experience with or interest in defending the 16-50 - just observing that different people have different opinions. I can't imagine that I'd have anything more to add on this subject. Last edited by Marc Sabatella; 07-11-2010 at 09:35 PM.*

07-12-2010, 04:48 AM	#17
rparmar Site Supporter Join Date: Jan 2008 Photos: Gallery Posts: 8,823	Originally posted by Marc Sabatella Once more, I have no experience with or interest in defending the 16-50 - just observing that different people have different opinions. Of course that is true. I think my "meta point" is that not all opinions are created equal. They must be analysed and evaluated using hard data. And trust, built up over time.

07-12-2010, 05:32 AM	#18
bdery Pentaxian Join Date: Mar 2008 Location: Quebec city, Canada Photos: Gallery Posts: 9,362	MTF evaluates the capability of a lens to create a sharp and "instantaneous" transition between black and white. Nothing more. It is generally also used for general sharpness, but that's simplyfing. You can beasure almost anything about a lens, honestly. All the aberrations (and I mean, ALL), disrotsion, contrast, sharpness can all be evaluated at the design stage, and verified after assembly. Don't put too much weigth on MTF. It's an interesting measurement, but not at all the holy grail of lens quality evaluation.