A Quick Play With HDR

Following some discussion in the camera club I have had a quick look again at HDR, and it is a very quick look. I had used HDR software in the past but I have had several PC incarnations since then and it was no longer installed.

I have just installed Enfuse and used the EnfuseGUI which can create HDR images and, I believe, also do focus stacking. It is open source and so costs nothing. I believe it can also be used as a plugin for Photoshop, Lightroom and Aperture. In that case you use Enfuse and a plugin.

I have put next to no effort into this and I think the results are quite presentable. Because it was so easy I thought I would share it. With a bit of experience who knows what is possible?

The image I have used is a view of the cricket pavilion in Robert’s Park.

Straight from RAW file

The image above is taken from the RAW file. Looking at the settings it looks as though I had very slightly tweaked it – brightened slightly, the contrast increased and the shadows darkened. The sky is a bit (?) nondescript to say the least.

After installing the software I went back to the original RAW file and saved 3 JPEG images from it after changing just the exposure.

Darkened

With this one I darkened the RAW image several f stops and then saved as a JPEG. The sky looks reasonable but everything else is too dark.

As is

This one is saved as a JPEG from the RAW file with next to no adjustments.

Brightened

This one is after brightening the RAW file and saving the resultant JPEG. You can now see a bit of detail on the scoreboard.

HDRd

And the last one is processed through the HDR software accepting the default settings.

I then went through each image and changed the size to 1200×757 and saved at 95% quality. I think the processed one looks quite good. It doesn’t glare at you and was very easy to do. If I was serious about it I should have taken 3 or 5 photos of the scene at different exposures and then worked with loss-less image file formats throughout until the final save as JPEG, but as I said, this was a quick trial and I am quite pleased with the result.

The reason for going back to the RAW file and changing the exposure is that there is much more data in the RAW file. Darkening the RAW file brings detail out of the clouds whereas if I had used a single JPEG the sky might have already been “blown out” – white, with no way of bringing out the contrast between some of the areas as it is darkened. Similarly with the dark areas. Also the JPEG file format looses data and the image can deteriorate every time it is saved.

For an image to render what looks like a wide dynamic range it must darken some areas and lighten others but transition carefully between them. This can cause one of the things I don’t like about some processed images. You can get halos around dark edges. You can often see this along a roof with the sky above. ┬áTo maintain the HDR effect the contrast between the roof edge and the sky is kept high in that area but then as you get further into the sky the sky must be darkened to bring out the clouds. This often means that there is a bright halo around the roof. This is one reason why it may be better, in some cases, to do the work by hand.