PL over-sharpening images from the OM 8-25mm f/4 lens

PL6 seems to badly over-sharpen certain textures in images created with the Olympus 8-24mm f/4 lens. The effect appears, or disappears, by activating or de-activating the “default” settings in the LensSharpness correction tool of PL.

LensSharpness is a recommended part of RAW image processing (see the DXO User Guide) and the over-sharpening cannot, as far as I can see, be compensated by other tools in PL (nor by local adjustments). Lowering the default ‘Global’ setting in LensSharpness does reduce (not eliminate) the problem but at the cost of a loss of overall image quality.

I have emailed DXO Support on this issue and hope they will be able either to clear up my mistakes or to correct the Optics Module for this lens on the OM-1 camera. I raise it here in case others have (or have not) found the same problem and have (or have not) found a work-around.

Here are two crops from an “actual size” image: one shows the image with LensSharpening “on” at the default setting and the other with LensSharpening “off”. I hope you can see that neither is good: in the first, the grasses have bright false-edges whereas in the second the colors are apparently more saturated (because of the absence of edge-sharpening) but the edges are blurry.

The pity of this is that the 8-25mm f/4 is a wonderful, sharp-edge-to-edge, landscape lens with very low or absent optical distortions and lovely ‘rendering’.



I am one who disagrees with DxO’s decision to set the default Lens Sharpening value to 1.00, because that adds noticeable edge artifacts. Most of my micro four thirds lenses give very sharp and clean results with Lens Sharpening set to 0.00 - so that is what I have baked into my default preset for RAW files. Note that a setting of 0 isn’t the same as turning the adjustment off. I think the only reason to leave it off is if you are using an unsharp mask or other software to apply sharpening instead.

It’s also important to not apply too much microcontrast if you don’t want fine details like tall grass looking white. If that isn’t a factor, and lowering the Global setting in Lens Sharpness isn’t working out as you say, then something might be going wrong in the demosaic stage of image processing, which I understand is when Lens Sharpness is applied. I would consider that a bug.

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Thanks, Greg. As you might imagine I’ve tried a variety of ‘work-arounds’. In general I find (with my other Olympus M4/3 lenses) the PL “Lens Sharpness” tool at the default setting works well.

I agree with your caution about ‘micro-contrast’. Like you I find no need for global sharpening of images processed in PL. The contrast delivered in OM-1 raws processed by PL without further user-adjustment is usually sufficient. At the margin, I use the Tone Curve if I want to touch-up the overall contrast of the image; rather than the specific Contrast panel settings.

But, as the DXO PL User Guide points out, lens sharpness is an optical property that even the best demosaicing of the raw file will not address. It’s a matter of ‘Airey disks’ and sensor (quantum) physics etc. The necessary corrections here are determined empirically by DXO and incorporated in the optics module for each lens/camera. “Lens Sharpness” is the means of enabling these corrections, which is why the User Guide advises leaving it set the default amount.

I’m wondering if the current Optics Module for the OM-1+Olympus 8-25mm lens needs revision. Perhaps the module was last verified for the Olympus versions of this camera (EM-I, II and III). The OM-1 has a newer, backlit “quad” pixel sensor that may have different characteristics. But this is just speculation on my part. Perhaps the module was revised for the newer sensor & I’m “holding it wrong” :blush:


One size fits all? I consider presets and their default settings to be a starting point only. If the result is not what I want, I change settings and work images individually, or, if I find a setting that works well in 80% of the images, I store it as a new preset.

Sharpness is only a technical property and is not that important to me…Which makes me like the oversharpened photo better than the other - because of the colour.

An important question is, might there be something wrong with some of DxO’s optics modules? Or is this an aberration of the lens? There are definitely cases where something’s going wrong and the cause is elusive. I’m working on two myself: with the Panasonic Lumix 12-60mm lens (which might be due to a filter I was using on that lens) and the Panasonic Leica 25mm f/1.4 lens (which can’t be explained that way).

…possibly, and DxO has updated modules in the past. Maybe DxO support will come forward with a proposal. Let’s wait and see. But again, if the lens is “a wonderful, sharp-edge-to-edge, landscape lens with very low or absent optical distortions and lovely ‘rendering’”, why applying extra sharpening?

Technique/ choice is irrelevant here. The OP is trying to identify the cause of DxO misbehaviour, not whether or not he needs to use the process. It ain’t doing what it says on the tin :grinning:

I know that it’s about possible module issues… but choice remains relevant…always.

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I agree, Its too much most the time. I have set mine to 0.00 and save it as default preset.

Its possible. I have a Sony lens that has wrong correction for vignette. I had to manually adjust it. I would advise if you find the correct settings for your lens to save the settings as preset and apply it automatically, once you know what works for what lens.


There is a bokeh slider in the “lens sharpness” panel and my understanding is that it adds a big of blur, probably guassian blur across the entire frame. Supposedly its supposed to reduce the effect of ever sharpening and artifacts. Unlike Global and details sliders which are calibrated per lens, bokeh slider affects the entire frame. My understanding is that its there in the case you want to apply sharlening per lens as it is calibrated by DXO and than use Bokeh to take the edge off, sort of speak of the overshapen look or if artifacts start to appear.

Have you tried that? If now, there is another approach, which is to reduce bokeh slider to zero and use less aggressive global and detail sliders, until you find the correct settings for your lens.

If it does, I haven’t noticed the blurring effect. Perhaps it depends on focal length etc. Unfortunately it does not seem to reduce the over-sharpening of high-frequency foreground subjects. In fact, I can’t see much impact with variations of the “Details” slider either at the 100% view that DXO says is necessary to see the corrections.

@PeterGallagher , would you mind posting (a link to) your original image and .dop files? The uploaded screenshots don’t show the issue here, in fact, the sharpening on the first image looks okay, while the second image looks blurry.

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I would love to play with the original image as well to try to figure out what is wrong.

That’s strange. If you can, please upload the original raw file for us to try.

In the manual of PhotoLab it says:

Lens sharpness

About optical sharpness

DxO PhotoLab’s exclusive DxO Lens Sharpness tool is one of its major strengths. Lens sharpness is an optical aberration which results in a point being transformed by the lens into a small blurred circle. (This should not be confused with out-of-focus or motion blur, which DxO PhotoLab does not correct.) DxO Optics Modules have been created by measuring the amount of blur for every point in the image area for each supported camera body and lens combination. By combining the shooting parameters saved in the EXIF metadata (aperture, focal length, etc.) and the information provided by the Optics Module, DxO PhotoLab can apply corrections that are tailored to each pixel in the image. These corrections are not uniform, given that lenses are sharper in the center, which means that the pixels closer to the edges of the image will be subjected to a stronger correction than those near the center.

The Lens Sharpness palette is visible only for images for which the appropriate DxO Optics Module is loaded. If no module is available, you should use the Edge offset slider in the Unsharp Mask palette to manually adjust the sharpness in image corners.

  • Global: Since DxO PhotoLab 6.3 (February 2023), the DxO Wide Gamut color space applies to both RAW and RGB files (JPEG, TIFF, linear DNG). The negative settings (from – 3 to 0) do not diminish the image sharpness, but result in more subtle corrections; in any case, the corrected image will be at least as sharp as the original. Even set at 0, the sharpness is greater than that of the original. To reduce sharpness (on a portrait for example) move the Global slider to the left; to increase it, move it to the right. The Lens Sharpness tool is what is known as an “intelligent” correction — one that is able to confine its effects to the noisy parts of the image, or when a photo was taken at high ISO.

It is important not to increase the sharpness of a shot that has already been sharpened by the camera, as is the case for JPEG images. So if you intend to post-process your images, you should shoot without any in-camera sharpening.

  • Details: The Details slider is set at 50 by default and is used to enhance the micro-contrast of fine details in the image. This subtle correction can be very worthwhile for use in landscapes, but should be reduced to a minimum for portraits, where a certain degree of sharpness is needed to hide (for example) skin blemishes.

Unlike the Unsharp Mask tool, enhancing details with the DxO Lens Sharpness tool does not create white edges or halos around the sharpened areas.

*** Bokeh: The Bokeh slider reduces artifacts in the bokeh (i.e., the out-of-focus area in your photos, mostly in the background) that can appear when using the sharpening tools. However, the slider will also have an influence on the sharp portions of the image.**

Lens Sharpness and Unsharp Mask

We recommend that you perform as much of your sharpening as possible using the DxO Lens Sharpness correction tool before using the Unsharp Mask. Of course, for images where the appropriate DxO Optics Module is not installed, you will have to use the Unsharp Mask for all manual sharpening tasks.

Personally I had a lot of success in tweaking these sliders to get what I want. Other than being a corrupt optics module for that lens and camera combination or some kind of corrupt data file of that module, I am fresh out of ideas and would love to try to test the original raw file to see if I can find out what is wrong.

Here is one of my examples. Show with a soft kit lens on a APS-C sony body.

As you can see I can dial in just the correct amount and makes a big difference. I think this is one of the big advantage soft lens sharpening feature in DXO.

If its not a problem, let us try your RAW file and we might find the problem.