My Lumix LX7 has an ‘high-dynamic range’ feature. Otherwise known by its initials ‘HDR’, high-dynamic range is a technique for digital imaging that allows greater detail in highlights and shadows by combining several images of the same subject that were exposed at different values.
The LX7 includes the HDR setting as one of the options in ‘scene mode’ (SCN on the selection dial). This rapidly exposes a sequence of images and combines them in-camera to produce a single HDR JPG. Obviously you need to hold still when you make the photo.
Also it helps to photograph a static scene or the result my get a bit weird.
In this instance, I photographed some flowers on the platform of NI Railway’s station at Whitehead, Co. Antrim (Northern Ireland).
This is my HDR composite photograph. The camera automatically exposes a burst of images at various exposure settings and combines them in-camera to produce a single image with greater shadow and highlight detail than is normally possible with a single frame.
There are other ways of accomplishing a similar result.
So I decided to compare the HDR with some manipulated versions of a camera RAW file that I exposed of the same scene. With the RAW images, I’d adjusted the file with Lightroom post processing software, selectively altering contrast, gamma, and colour saturation and colour temperature to make for a more pleasing photograph.
Specifically I applied a digital graduated neutral density filter, while making global changes to highlights and saturation.
The output of the RAW is also as a JPG, which I scaled for presentation here.
This view is from a single RAW file exposed with the Lumix LX7 and manipulated digitally to maximize highlight and shadow detail. This is my first of two manipulations.This is a more intensively manipulated file than the image immediately above. Again this image was from a single camera RAW file. This one features slightly darker highlight values.
I made two versions of the RAW interpretation.
In both sets of images I’ve intentionally focused on the flowers and not the NIR train.
Among the built-in features of the Panasonic LX7 is a HDR—High Dynamic Range—setting in ‘Scene Mode’.
The theory behind HDR is the ability to produce a digitally exposed photograph with better highlight and shadow detail through post-processing blending of two or more images of the same scene exposed at different light settings. (In other words, a multiple exposure).
A common way to accomplish this is to place the camera on a tripod and make three images of identical composition with one image over-exposed (too light), one normally exposed, and one underexposed (too dark). Then combine all three images as multiple exposure.
When done effectively this can be used to overcome the limited dynamic range inherent to digital sensors. It can also be used creatively through extreme exposure variations to produce some outlandish images with nightmare skies and penetrating shadows.
The LX7s feature makes exposing a basic HDR style image exceptionally easy as the camera automatically takes three photos in rapid sequence and processes them immediately in-camera to produces a blended Jpg available for viewing.
I found this most effective in high contrast scenes, such as sunsets, that might be difficult to capture because of the camera’s limited exposure range. In other situations, it seems to flatten the contrast and doesn’t necessarily make for a more pleasing photograph.
Another point, if the scene isn’t static, ‘ghosting’ will occur of moving elements. My sense is that camera’s software must have a comparative feature that attempts to minimize the effect of ghosting, but the results can appear unnatural if not outright bizarre. Especially, when the subject, say a passing locomotive, become transparent!
Below are a few of my experiments. With most I’ve first included a comparison image (an ordinary non-HDR photo) exposed in the normal way.
This is the non-HDR normal photo. I’ve intentionally selected a high contrast scene to test the difference between a normal image and the HDR. Princeton Junction, exposed with Lumix LX7 in ‘A’ mode.Exposed in HDR mode. Notice that this does a much better job of retaining shadow and highlight detail. It is easier to see into the cab of the train and the clouds are better separated from the blue sky. Princeton Junction, exposed with Lumix LX7 in HDR ‘scene’ mode.This NJ Transit train had paused at Princeton Junction in high midday June sun making for an ideal opportunity to test the effect of HDR. This my ‘normal’ non-HDR comparison image. Note the nearly opaque underside of the locomotive where wheels and equipment are lost in an inky black. Princeton Junction, exposed with Lumix LX7 in ‘A’ mode.This is the HDR photo of the same scene. By using multiple exposures, the HDR feature has added detail to the shadows making equipment on the underside of the locomotive more visible. I’m not sure if I like the effect on the trees, which to me seem like a painted backdrop compared with those in the normal photo above. Princeton Junction, exposed with Lumix LX7 in HDR ‘scene’ mode.I thought I’d try the HDR feature on a rapidly moving train. One of Amtrak’s Keystone trains is passing Princeton Junction at speed. Notice the effect of double exposure where the cab car is ghosted into the coach. This is curious aberration, but probably not the best solution for railway action photography. I don’t have a ‘non’-HDR image of this scene. Princeton Junction, exposed with Lumix LX7 in HDR ‘scene’ mode.This high contrast scene at Overbrook, Pennsylvania in early July 2014, made for another opportunity to make comparisons. This is the ‘non-HDR’ image, exposed with Lumix LX7 in ‘A’ mode.SEPTA at Overbrook, exposed with Lumix LX7 in HDR ‘scene’ mode.Sunset at CP83 in Palmer, Massachusetts. Owing to the extreme contrast of the scene, I opted to expose for the sky in the normal (non-HDR) image. If I exposed to make the tracks lighter, I’d lose the effect of the sunset. Exposed with Lumix LX7 in ‘A’ mode.Here’s the HDR image. While it retains sky and track detail, it radically altered the effect of sunset. Is this a more realistic portrayal of the scene? Exposed with Lumix LX7 in HDR ‘scene’ mode.View of an Irish Rail ballast train at Islandbridge Junction in Dublin. This is the ‘non-HDR’ comparison, exposed with Lumix LX7 in ‘A’ mode.While waiting for the ballast train to get the signal, I took the opportunity to make an HDR comparison. It was free, so why not? However, I don’t think this improved the scene, now it just looks washed out to me. Exposed with Lumix LX7 in HDR ‘scene’ mode.
This is a work in progress, and I’ll follow up in more detail in a later post.
