"In-camera" chromatic aberration issues

stevebrot · 06-12-2014, 10:40 PM

Originally posted by kh1234567890

It is the linear resolution that matters as far as any increased visibility of CA etc. goes. The K-3 sensor is a touch smaller so the pixel spacing is about 3.9um for the K-3 vs 4.8um for the K-5. Less than 25% difference in whichever direction you measure.

I think this is somewhat different than your original assertion and definitely makes more sense. Is this the same as pixel pitch? If I remember correctly it is pixel pitch that influences the theoretical maximum horizontal/vertical optical resolution, which is what counts in this context.

Regardless, I was not impressed with that aspect of the camera review and was still left wondering which Pentax models handled CA better.

Steve

rawr · 06-12-2014, 11:01 PM

I think the camera reviewer is simply used to reviewing other camera makes (eg Nikon), where the in-camera CA correction seems to be turned on by default, and may be more effective than the Pentax default.

Anyway, the CA performance of this lens in the sample image is as expected. As the SLRGear test of this lens reminds us:

Quote:

"Chromatic Aberration
Below 100mm, chromatic aberration is tolerable - just some light color fringing in areas of contrast, and only in the extreme corners. ..."

which is where we are seeing it here.

Luckily the reviewer in OP's post didn't examine any shots taken with the lens at 100mm or greater

. Also from the SLRGear test:

Quote:

As the lens is zoomed in to 100mm and 135mm however, chromatic aberration is quite prominent, in fact, some of the most noteworthy we've come to see in these tests.

Having said that, CA hasn't really been a problem with my copy of this lens at any focal length.

stevebrot · 06-13-2014, 02:21 AM

Originally posted by rawr

Having said that, CA hasn't really been a problem with my copy of this lens at any focal length.

Or my copy of the K-3

Steve

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06-12-2014, 10:40 PM	#16
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by kh1234567890 It is the linear resolution that matters as far as any increased visibility of CA etc. goes. The K-3 sensor is a touch smaller so the pixel spacing is about 3.9um for the K-3 vs 4.8um for the K-5. Less than 25% difference in whichever direction you measure. I think this is somewhat different than your original assertion and definitely makes more sense. Is this the same as pixel pitch? If I remember correctly it is pixel pitch that influences the theoretical maximum horizontal/vertical optical resolution, which is what counts in this context. Regardless, I was not impressed with that aspect of the camera review and was still left wondering which Pentax models handled CA better. Steve

06-12-2014, 11:01 PM	#17
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	I think the camera reviewer is simply used to reviewing other camera makes (eg Nikon), where the in-camera CA correction seems to be turned on by default, and may be more effective than the Pentax default. Anyway, the CA performance of this lens in the sample image is as expected. As the SLRGear test of this lens reminds us: Quote: "Chromatic Aberration Below 100mm, chromatic aberration is tolerable - just some light color fringing in areas of contrast, and only in the extreme corners. ..." which is where we are seeing it here. Luckily the reviewer in OP's post didn't examine any shots taken with the lens at 100mm or greater . Also from the SLRGear test: Quote: As the lens is zoomed in to 100mm and 135mm however, chromatic aberration is quite prominent, in fact, some of the most noteworthy we've come to see in these tests. Having said that, CA hasn't really been a problem with my copy of this lens at any focal length.

06-13-2014, 02:21 AM	#18
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by rawr Having said that, CA hasn't really been a problem with my copy of this lens at any focal length. Or my copy of the K-3 Steve