Originally posted by causey In particular, has anyone noticed improvements in this respect after DxO processing of pictures taken with Pentax 18-250mm
It improves the corners, as it does the center, for this lens. Nevertheless, the corners still suck. However, just not that much anymore. I attached an example (forgive the photographic quality -- I normally don't keep both PEF and DNG ...)
The original is PEF developed with LR.
The DxO image is processed by DxO with lens corrections only (distortion, vignetting, lens softness), saved as DNG, and then treated by LR like the original.
The efficiency of DxO is lower at high ISO. But nevertheless, DxO brings the quality of the 18-250 on par with standard zooms.
A comment regarding the sample shown below:
You can increase sharpness in the original using an UnsharpMask filter (USM). For the border crop, a radius of 4px and intensity of 200% must be used in an attempt to approximate the DxO quality. Still, the DxO crop has lots more detail. Moreover, if you apply an USM (radius 1px, intensity 100%) to the DxO crop, then you obtain a perceived sharpness not feasible with the original crop. And more detail. So, the effect cannot be reproduced in Photoshop...