Processing RAW using DxO - post your samples and tips - Part II

DxO's deep prime de-noise is great for high ISO shots. I wondered it could help get 'reasonable' shutter speeds for infrared landscape photography using an IR filter (such as the Hoya R72) on an unmodified camera on very fast wide-angle lenses at their widest apertures, and pushing the ISO for photos.

The problem with IR photography with unmodded cameras is the shutter speeds are very long, often 10-30 seconds, causing blurred foliage if there's any wind. (Cameras can be custom modified for IR photography at 'normal' shutter speeds by removing the sensor's internal IR filter.)

I gave this a try with various native EF-M mount lenses and my Canon M6ii...

I used my Canon M6ii, and a Hoya R72 filter in 67mm size, which fits the Sigma 16mm f1.4 C lens and Rokinon 12mm f2 MF lens I have, and step-up rings can be used with my other lenses.

I tried my fastest wide-angle lenses: the Rokinon 12mm f2, Sigma 16mm f1.4, and Canon 22mm f2 lenses. The Rokinon was OK, however it has a 'hot spot' in the center at f2 and f5.6, and the edges of the frame were blurred due to focus or field curvature differences that lens seems to have with IR light, so I didn't go far with it and results for the Roki aren't shown here.

The Sigma 16mm f1.4 worked well... it had a mild hot spot in the center at f1.4 and f4.5, but the spot was correctable with a mask - reducing exposure of the spot by -1 EV and increasing the contrast and microcontrast slightly. Results below.

The Canon 22mm f2 also worked fairly well, however at f2 it has significant corner vignetting, which degraded the f2 high ISO corners noticeably. Results also shown below.

Here's a shot with the Sigma 16mm f1.4 lens in normal 'visible' light at f4.5, at ISO 100, with no filter:

Canon M6ii, Sigma 16mm f1.4 at f4.5, 1/1000s, ISO 100

Here's the same scene with the Sigma 16mm f1.4 f1.4 lens in infrared light, with the Hoya R72 filter (67mm filter size) at ISO 100:

Canon M6ii, Sigma 16mm f1.4 at f4.5, Hoya R72 filter, 10s, ISO 100 (pushed to ISO 400 in post)

The shot above was white-balanced to Temperature of 2100K and Tint of -66, Reds punch up +40 and Blues and Greens dropped -66, Exposure compensation in post +2.13, Contrast +53, Microcontrast 20. Saturation +90, Vibrancy unchanged. (Processing infrared color images is subjective, there's no right or wrong, it's mostly getting an image that is to your taste.) My goal was to get some color that looked fairly neutral, with a tonal range and 'look' that was somewhat like the visible light image.

The problem with a long shutter speed of 10 seconds is that a light wind blew the tree branches around, blurring them...

By shooting with the lens wide open at f1.4, and shooting at ISO 1600 in camera (pushing to about ISO 8000 in post), I was able to get a shutter speed of 1/15s which reduced the blurring of the foliage quite a bit:

Canon M6ii, Sigma 16mm f1.4 at f1.4, Hoya R72 filter, 1/15s, ISO 1600 (pushed to ISO 8000 in post)

Very similar tone and color processing as the f4.5 image - the main difference is that this image was pushed 2.43 EV in post to about ISO 8000 and Deep Prime Denoise setting was set to Luminance 70 instead of 40, to reduce the high noise level to a 'light grainy appearance'. ISO 1600 gave the correct initial exposure that did not oversaturate the red channel, but after color balancing the overall exposure needed to be pushed.

Here's the result using the Canon EF-M 22mm f2 lens at f4.5:

Canon M6ii, Canon EF-M 22mm f2 at f4.5, Hoya R72 filter, 8s, ISO 100 (pushed to ISO 400 in post)

And the Canon EF-M 22mm f2 lens at f2 at high ISO and a faster shutter speed to avoid blurring the foliage:

Canon M6ii, Canon EF-M 22mm f2 at f2, Hoya R72 filter, 1/10s, ISO 1600 (pushed to ISO 6400 in post)

Note the degradation in both color and grain in the corners of the f2 shot due to the vignetting correction pushing the corners to a more extreme ISO.

All images above are uncropped but downsized to 2160 pixels high (web or 4k monitor resolution). Deep Prime de-noise was adjusted so the grain at this image size was balanced between having good detail and sharpness for the high ISO shots without washing out to a 'watercolor' appearance.