High ISO with DPP should and can be better

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We have already established that Canon’s current noise reduction system is excellent. However, you can only take advantage of the new system by using JPEGs produced internally by the camera (As of today the EOS 40D, the EOS 1D Mark III and the EOS 1Ds Mark III are using Canon’s new noise reduction system).

Many of us use RAW these days, and some of us prefer to use DPP due to the excellent picture style system. You should be aware however, that the results you get out of DPP with high ISO images are not as good as the JPEG out of the camera. There is a quick fix you can do to produce better results, but it is really something Canon should address back in Tokyo.

Noise reduction and user controls

DPP allows you to define three intensity levels for both Luma filtering and Chroma filtering separately. By default, these controls are set to OFF, this does not mean there is no noise reduction at all, just that the intensity of filtering is somewhat reduced.

You can set noise reduction to Low and High settings, while there are some advantages to the Low setting in low ISO image, at high and medium ISO images it is best to set both controls to the high setting.

The example below is a 100% crop from our studio scene which we captured using the EOS 1D Mark III at 3200ISO. Move your mouse between the buttons to view the results.

100%
DPP OFF DPP Low DPP High

Next to the camera

Most photographers would think that RAW will always produce better image quality than the JPEG file of the camera. In some cases, depending on the RAW software being used, the results are better. The example below shows the difference between the original JPEG out of the EOS 1D Mark III and DPP set to high.

100%
DPP High EOS 1D Mark III JPEG NR ON

As you can see, DPP is able to produce sharper results than the camera. However, on flat areas (areas that do not contain edges) and dark areas, DPP does not produce results that are as pleasant as the JPEG out of the camera. The flat areas of the image contain many small bright “dots” that disturb the viewer. Those “dots” may produce the illusion that there are more details in the image, especially when viewing the image with small enlargement percentage.

This is only an illusion, as you can see from the example below, DPP does not show more details than the JPEG out of the cameras.
You must distinguish between details and sharpness. A sharper image does not mean it holds more details, it means the large dominant edges are simply sharper.

100%
DPP High EOS 1D Mark III JPEG NR ON

When looking closely (300%) at the DPP results, you can see that some pixels are brighter than the environment they are in. In other words, they are brighter than the average and some are darker than the average. This phenomenon will be very familiar for those of you who tuned or designed noise reduction algorithms and it is called “filtering holes”. These “holes” are small pixel groups that were not filtered.

300%
DPP High EOS 1D Mark III JPEG NR ON

This phenomenon takes place when thresholds that are set to distinguish between pixels that need to be filtered and pixels that do not need to be filtered (or filtered differently) are too low.
In this case, if the average of a group of pixels exceeds the threshold value, no filtering will occur. The results below in 300% view shows how well the EOS 1D Mark III is tuned compared to DPP.

Both the noise reduction system and the edge enhancement (sharpening) system could produce such poor results. To understand which system is responsible, we conducted a simple test.

By closing the sharpening setting completely in DPP but leaving the noise reduction settings on high, we took the edge enhancement algorithm out of the equation. We then applied an unsharp mask filter using Photoshop with the following settings:

Amount: 150
Radius: 0.7
Threshold: 0

We applied the same filter on the JPEG out of the EOS 1D Mark III to understand which file was filtered better. You can view the results below.

300%
DPP High EOS 1D Mark III JPEG NR ON

From these results we conclude that DPPs noise reduction thresholds are probably configured lower than the noise reduction thresholds of the EOS 1D Mark III. Assuming of course that the noise reduction algorithm is the same. Ultimately it is likely that both DPPs edge enhancement and noise reduction thresholds require improvements.

It is to be expected that Canon should try to extract more details or to produce a sharper image with DPP. But I feel that the price Canon and all Canon’s users are paying is too high. I generally prefer the results from the EOS 1D Mark III JPEG file rather than the results from DPP with high ISO images.

Since there is no way for the user to tune thresholds, the best thing we can do for now is to lower the sharpening level to 1 or even 0, while keeping the noise reduction setting on high for high ISO images. By doing so, the results won’t be as sharp as before, but the flat DC areas will appear more pleasing with less filtering holes.

By toggling between the images below you can see that as the sharpening level is reduced, less filtering holes appear.

100%
DPP NR High sharpening 3 DPP NR High sharpening 1 DPP NR High sharpening 0 EOS 1D Mark III JPEG NR ON

Final words and recommendation

It is expected for RAW software to produce more details and sharper edges. But the way this is implemented in DPP is not good enough. There are improvements to be made, and I think Canon can improve the results easily by simply improving the tuning of the algorithms.

Furthermore, I think canon underestimates the importance of defaults values. With the current DPP defaults values, high ISO images are not as good as the EOS 1D Mark III JPEG file. I would like to see DPP configured to its best for each ISO setting and for each camera model. The same way it is done with DIGIC III for each camera Canon has made. The user should then tune the image according to his preferences by using the controls.

Compared with the camera DPP does produce more detail in some very specific areas. It is most likely that the internal sharpening of the EOS 1D Mark III is reduced when the camera is set to high ISO levels. Therefore, by sharpening the JPEG of the EOS 1D Mark III, we can see how well the internal noise reduction is configured, as the images below show.

100%
DPP NR High sharpening 3 EOS 1D Mark III JPEG NR ON + Photoshop USM EOS 1D Mark III JPEG NR ON

As you can see by toggling between the images, the JPEG file could be sharpened to produce sharper edges but without introducing artifacts at flat areas. This means that the configuration of the noise reduction algorithms inside the EOS 1D Mark III is probably better for flat areas. It’s worth noting that DPP seems to filter Chroma edges slightly better.

Recommendations for Canon

* Configure thresholds and algorithms to exceed or match the image quality of the camera, while producing pleasing grain.
* Configure the default values of both sharpening and noise reduction to match the camera. Do not keep noise reduction levels OFF while the camera clearly is configured differently.
* Improve edge detection in order to extract more details and improve edge sharpening while making sure the flat DC areas are not affected so as to give an unpleasing result.

Recommendation for DPP users

For now, I would recommend to set the sharpening level in DPP to 0 or 1 in order to avoid emphasizing the flittering holes with high ISO images. It is also possible to set noise reduction to HIGH (both) and set the sharpening level to 0. Then, use solutions such as Noise Ninja to “fix” the filtering holes Canon left behind. The last stage should include sharpening using your favorite tool.


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