Recovering a -2 EV Underexposed Image From Olympus XZ-1

Our grand nephew insisted we join him and his family to the cinema one evening. Unfortunately the movie he wanted to watch was taken off for the day's screening. Feeling disappointed and dejected he was not in the best of mood so we decided to have dinner first before thinking how to fill our time for the rest of the evening.



Kids being kids, after dinner he got over the disappointment  and was running all over the mall and posing for photograph. My wife was pleasantly surprised by his happy mood and quickly pulled out her XZ-1 and started snapping away.  He and his little sister were happily posing in front of the lighted fountain at the mall entrance but the tiny flash from the XZ-1 did not have sufficient power to cover the whole scene. On top of that the alternating fountain lighting from bright to dark accompanied by ever changing coloured illuminations fooled the camera metering.

2 stop underexposed photo from Olympus XZ-1 digital camera
A 2 stops underexposed photo from the Olympus XZ-1 in Normal Program Pattern metering mode — Camera: Olympus XZ-1. Setting lens zoom at 28mm(35mm film) or 6.0mm(lens) and at f/1.8 1/30s, ISO 100, Built-in flash On

This photo with both of them in front of the fountain was about 2 stops under exposed. With the images loaded on the computer we tried to recover the images from the RAW files. On the Olympus Viewer 3, I set the Exposure value to + 2 EV or 2 stops over which is the maximum setting available on Olympus Viewer 3.

The recovered image looks good, the colour vibrant and Olympus Viewer 3 has kept the noise level at an acceptable level. I am amazed at how good this small 1/1.63" old fashioned CCD sensor that many people thought as outdated, on the XZ-1 is doing.

After seeing the result from the Olympus Viewer 3, I decided to try this on the Darktable; the raw processing and work flow software on Linux computer. Darktable is very powerful but with a different and sometimes geeky user interface. I had toy with Darktable for a while but yet to commit to it seriously.

2 stop increase in exposure in Darktable Raw Conversion Olympus XZ-1
The same image as before but with a 2 stops increase in exposure during RAW conversion using Darktable — Camera: Olympus XZ-1. Setting lens zoom at 28mm(35mm film) or 6.0mm(lens) and at f/1.8 1/30s, ISO 100, Built-in flash On.

Comparing the result I got from both theDarktable and Olympus Viewer 3 they are very close. The Darktable seems to do better with more details in the mid tone area on the fountain itself while the Viewer 3 is better in protecting the highlight. The Viewer 3 also did better in the noise reduction but the Darktable had many ways to denoise - I tried the Profile Denoise feature on Darktable and found it to perform very well. Darktable is more flexible with what you can do with the images but that also makes it more complicating. The Olympus Viewer 3 has limited set of settings but is a much easier software to master yet produce good result.

After looking at the recovered images and the original images I got an idea to Exposure Blend the recovered image with the original together. Olympus viewer 3 and Darktable both do not have Exposure Blend features in the current version of the software. So the Blending part goes to The GIMP and the blended and tone mapped image overall looks better than the +2EV photo with more contrast and details especially on the illuminated sign and lamps in the photograph.

Result of  the -2EV underexposed image blend with the RAW converted Image.
Exposure blending the two previous images to form this final photo — Camera: Olympus XZ-1. Setting lens zoom at 28mm(35mm film) or 6.0mm(lens) and at f/1.8 1/30s, ISO 100, Built-in flash On.

The only draw back is the blended image has more noise but that can be taken care of with the Wavelet Denoise on Gimp. For web use like on the blog or social websites the noise on the blended image should not pose any problem with the image scaled down to web-ready image size.

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