A Brief Tone Mapping Guide To iCamera HDR

Tone mapping is your friend.

by Pu on May 25, 2011

Dynamic range is the ratio between maximum and minimum light intensity (or white and black, to say it more plainly); it varies a lot depending on the medium. The human eye is a highly sophisticated instrument, able to perceive the world in its complexity more efficiently than most artificial devices. It’s a crucial problem for photographers to be able to capture a scene in all its tonal richness, overcoming the technical limitations of the camera medium.

In digital photography, tone mapping is a technique allowing to process images so that they display a wider range of tonal detail than the medium allows. This technique permits to make up for technical deficiencies of cameras, monitors, printers, etc., bringing out what seems to be either lost in the shadows or in the highlights. HDR photography heavily relies on tone mapping processing.

iCamera HDR uses three different tone mapping engines for creating HDR composites. What are the differences and when to use them? Read on to know more.

  • Tone Balancer
    Tone Balancer is a local tone mapping engine. Local means the engine processes each pixel extracting information from its surrounding area. Tone Balancer is aimed at balancing light and dark areas in pictures, so that resulting images are highly contrasted and sharp; the negative side concerns the fact the images often feature exaggerated, unreal colors, frequently in combination with intense halo artifacts. 

    iCamera HDR - Tone Balancer

    Image processed with Tone Balancer

    Adjustable parameters in Tone Balancer:
    Strength – Sets the contrast of the image;
    Local lighting – Sets the brightness of the image.

  • Tone Enhancer
    Tone Enhancer is also a local tone mapping engine, which means pixels are processed according to their local context. Differently from Tone Balancer, Tone Enhancer is more targeted at bringing out fine detail. Images processed with Tone Enhancer are not as “overdone” as those processed with Tone Balancer (their colors are especially much more realistic), but they are also prone to feature emphasized halo artifacts and noise. 

    iCamera HDR - Tone Enhancer

    Image processed with Tone Enhancer

    Adjustable parameters in Tone Enhancer:
    Strength – Sets the color saturation of the image;
    Fill Light – Reduces contrasts and lights up dark areas of the image.

  • Tone Compressor
    Tone Compressor is a global mapping engine. Global means that every pixel of the image is processed in the same way, regardless of the values of other surrounding pixels. The resulting images lack in contrast, but they are also less likely to be affected by halation and noise. Tone Compressor delivers more natural looking images, at the expenses of detail. 

    iCamera HDR - Tone Compressor

    Image processed with Tone Compressor

    Adjustable parameters in Tone Compressor:
    Strength – Sets the global contrast of the image.

Closing comments
Which among the three tone mapping engines in iCamera HDR is the best? Which among them will make photos look better? These and other similar questions are frequent among iCamera HDR users. However we look at it, there is not a general rule as to what is more proper to use to process photos in iCamera HDR. It all depends on what kind of effect you are looking for and on what photos you are going to use. The best suggestion is not to stick to a single processing, but to try for every image different solutions, knowing before starting what kind of feeling and look you want to convey.

Jay May 25, 2011 at 4:20 am

Thanks for posting this. I like iCamera HDR, but was lost when it came to those 3 settings.

Mar May 25, 2011 at 3:42 pm

Thank you! I use Tone Compressor for portrait shots, particularly indoors at night with artificial light. It complements skin tones very well, and brings out lost details in dark hair.

Why are the three pictures you show all gray? Only the sky has some color. Was it shot at night?

Pu May 25, 2011 at 4:00 pm

They’re not supposed to be all gray, haha. The picture was shot in overcast weather and a little before sunset, so that apart from the sky, the color in the images perhaps doesn’t stand out much. Maybe I should change them to something more colorful =)

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