HDR tools - Comparison

HDR imaging is becoming more and more popular in digital photography world. The creation of hdri gives a number of challenges to software developers, with merging and tone mapping the most important of them. The versatility of programs gives the user a choice and we are trying to give some guidance as to how to choose properly.

This last article in the series is devoted to comparison of all the reviewed hdr making programs. We shall look at the default results of each of them and compare them using basic quality characteristics such as alignment, ghost artifacts, tonal compression, noise, etc. The illustrations set side by side will speak for themselves in most cases.

The source images for the example were taken with Nikon D 80 camera at ISO 400.

First we compare alignment and ghosting artifacts avoiding jobs. The fragments are marked in a bigger image.

Auto alignment works fairly well in all the programs. Though on the margins of the images some minor shifts are still present. Note also the blue and red stripes on the edges.

Not even so good is the performance with ghosting artifacts that can appear when moving objects are present in the image.

Only Photomatix and Digital Photo HDR have any tools for dealing with such occurrences. Both are not performing ideally but still do better than nothing. Digital Photo HDR has a better result to our consideration. It only produces light traces of the masking tool but these can be retouched away quite easily. Photomatix deals with second and third ghost like figures and leaves only one of them but those have mistakes and need substantial afterwork. This makes Digital Photo HDR the absolute leader in this sphere.

The waving leaves in the same photo mostly display very poor job at a closer look.

Only Easy HDR, Enhancer, and Photoshop show no mistakes. Photomatix produces too dark shadows (which is one of its characteristics overall), Artizen also looses part of the shadows, Digital Photo HDR performs with mistakes and clear double lines without its mask option used (the use of the mask on big areas has its disadvantages, see the article). As for the noise, the amount is most the same for every program.

Now to the quality of the tonal compression job. Below you see the default tone mapped hdr images created with every one of the six reviewed tools. The images were aligned automatically. These are the images as you will see them after the tone-mapping process is finished.

As you see tone mapping methods of different programs produce rather different results. That is partly due to the fact that different methods are placed as default. In Photoshop and Photomatix, for example, first go the global operators; Digital Photo HDR clearly uses some local operator as seen by distinct halos around some objects.
We did not show here all possible tone-compression methods results, you can have a look at them in the corresponding articles, but simply took default settings and operators.
Photoshop tone mapped image colors are a naturally looking with not too much contrast. The highlights are a little clipped though and the clouds show a bit unnatural gradient. Nothing that cannot remedied by fine-tuning the settings though.
Photomatix produces a more contrasted image with deep, to the point of clipping, shadows and bright colors. The sky at the top of the image is too deep blue to our mind.
Digital photo HDR processed image stands very close in contrast and brightness to Photomatix but without its deep shadows.
Easy HDR is a shade lighter than the latter two.
Enhancer is ok with overall colors but some dark blue grain shows in the sky.
The last comes Artizen with distinct halo around the clouds in the sky again.

Below is a table with basic hdr making programs functionality compared:

	Photoshop	Photomatix	EasyHDR	Artizen	Enhancer	Digital Photo HDR
Aligning	Auto	Auto	auto	auto	auto	auto manual
Tone mapping (global operators)	Exposure and gamma Highlight compression Equalize histogramm	Tone compressor	Mask unchecked	Display	HDR mode	Eye catching Ultra contrast Photographic
Tone mapping (local operators)	Local adaptation	Details enhancer	Mask checked	Lock05 Lock06 Fattal Cipher	no	Smooth compressor Autoadaptive Human eye
Ghost reduction	no	yes	no	no	no	yes
Post processing	yes	no	no	yes	yes	yes
Extra effects	yes	no	no	yes	yes	yes