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17-50mm Lens on an SD1 Merrill - Sharpness Field.

Started Aug 24, 2021 | Discussions thread
Scottelly
Scottelly Forum Pro • Posts: 18,028
Re: 17-50mm Lens on an SD1 Merrill - Sharpness Field.

xpatUSA wrote:

I'm reading about Lens Field Curvature in articles by Roger Cicala (he of Lens Rentals fame). I've also read comments here about a significant field curvature from the 17-50mm. Cicala mentions that the field curvature of a lens can be shown by shooting grass and then applying Edge Detection to the resulting image:

https://www.dpreview.com/opinion/4042117089/roger-cicala-why-i-dont-use-an-mtf-bench-to-test-my-own-lenses

I intend to do that soon with my copy of the 17-50mm, set at f/2.8 and a few different focal lengths.

Nice!

But, meanwhile, I tried out Edge Detection on a shot taken at 23mm focal length with the said lens:

The usual test scene ...

Focus was on the far tree tops about 600 ft distant. SPP settings were all at default, including Sharpness. Algorithm was Laplace as found in the GIMP - there are others ...

Not the best scene for Field Curvature, but I'm beginning to wonder why I sold the SD1

I'll swap it for an SD Quattro H, if you can get hold of one of those Ted.

Merrill.

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Scott Barton Kennelly
https://www.bigprintphotos.com/

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