It’s Travel Photography Month here on Too Many Adapters – all photography all the time for the entire month of August! With tips and tricks, gear reviews and great advice from some amazing travel photographers, this is the place to be if you want to take better shots of the world you’re travelling through.
In today’s post I’m going to give an overview of a photography technique known as High Dynamic Range photography, or HDR. It’s a style of photography which, similar to the novelty of sound being introduced in the movies way back when, has the ability to hugely polarise opinion as to whether or not it should be used.
I say, do what makes you happy as a photographer, and what resonates with your followers. There’s no such thing as pure photography, just people who like to air their opinions.
That said, HDR is just another tool, and can’t turn a poorly composed image into a masterpiece. No matter how much lipstick you stick on a pig… well… you get the idea. For more thoughts on composition and taking photographs that suck less, check out this post from earlier in the month by Kirsten Alana. In the meantime, let’s get on with this.
What Is Dynamic Range Anyway?
The dynamic range of something is the bit between the maximum and minimum of a changeable quantity. Sounds complicated? Well, let’s think of the human eye. We can see things that are very bright, on a sunny day for example, and we can see things that are very dark, say on a starry night.
We can’t do both at the same time, as the eyes take time to adjust, but the difference between the brightest object and the darkest object that we can identify in any particular scene is significant, and this is referred to as our dynamic range.
The human eye has a much greater dynamic range than a camera. You’ve probably observed this phenomenon for yourself when taking pictures, perhaps from a shady spot with a bright sunny sky in the background.
Either all the shade disappears into blackness, and the sky is perfectly exposed, or the sky is just white, whilst the shade looks good. Yet your eye reveals a perfectly balanced image.
Here’s an under and overexposed version of the same image to give you an idea.
This can be frustrating when you just want to capture the scene in front of you. And this is where HDR can help out.
How Can HDR Help?
High Dynamic Range, as the name implies, is a technique that allows you to capture an image with a higher dynamic range than your camera could otherwise manage.
It works by taking multiple photographs of the same scene at different exposures, and then combining them into a final image that takes the best exposed parts from each image, resulting in an image with a high dynamic range.
Let’s talk examples. Take a look at the shots above of the church. This image was shot directly into the sun, which is obviously a fairly powerful light source. Each image shows the three different exposures that this was taken with, just arranged differently.
The difference between the far right images featuring the sun are most pronounced. In the underexposed shot (bottom) we can see clouds on the horizon and around the sun, whereas the valley is just a black abyss.
In the overexposed version of the shot (top), this situation reverses, and the sky turns into a white washout, while the valley and contents are clearly discernible.
Using HDR, we can take the useful parts of both of these images, and turn them into something closer to the reality of the actual scene.
Gear You Are Likely to Need
So that is what HDR is for. Now let’s talk practicalities.
The easiest way to take images for use in an HDR environment is to use a camera that lets you “exposure bracket” your images. This means that the camera will take a number of images automatically when you depress the shutter.
These will consist of a normally exposed image, an underexposed image and an overexposed image. This setting is often referred to as AEB, or auto exposure bracketing, and is featured on a great number of cameras – check your manual to figure out where to find it.
You will usually have the option as to how many stops of under or over exposure you want to shoot. This will depend on the nature of the scene, and the difference between the bright and dark areas, but in most cases a setting of +/- 1 or 2 will suffice.
Some more advanced cameras will also let you decide how many images you want to take – for example you could take just three images, exposed at –2ev, 0ev and +2ev, or you could take five images, at –4ev, –2ev, 0ev, +2ev and +4ev. The greater the dynamic range of the scene, the more images you will probably want to take in order to get all the details.
When shooting multiple exposures of the same scene, you are going to want to make sure your camera doesn’t move between exposures. The easiest way to do this is with a tripod.
Ideally, to eliminate shutter shake (the movement of the camera as you press the button), you will also use a remote release switch, but this isn’t critical.
If a tripod isn’t available, then finding some nearby scenery to rest on will work most of the time, although you can’t always frame the scene how you wish.
The key part of creating an HDR image is the software processing. Merging your images of varying exposure into each other requires some effort on a computer and the use of a dedicated software package.
There are a number of options on the market – here’s a quick run through of three of these:
Luminance HDR was the first HDR program I used, and it has the huge advantage over other software of being free. It’s also open source, if that sort of thing floats your boat.
It is certainly capable of producing great results with the right input, but the interface isn’t very intuitive, and control over your final image is fairly limited. Free, available for Windows and Max OS X.
Nik Software HDR Efex
Part of the Nik Software product suite, now owned by Google, HDR Efex is an interesting tool for creating HDR images that is both easy to use and powerful.
It has a host of editing options and the interface is very user friendly, but it doesn’t have quite the fine grained control compared to the next product on this list.
Its main advantage though is that it is available as a software bundle from Google for around $150, which includes a whole host of photography tools, including the excellent Sliver Efex, Viveza, Dfine Noise reduction and more. These are fantastic additions to any photography editing toolkit, and so I can still recommend this product as an alternative option.
Available for Mac OS X and Windows, either standalone or as a plugin for Adobe / Aperture software.
Photomatix Pro & Photomatix Essentials
Photomatix by HDRsoft is the benchmark when it comes to HDR software. It’s also the tool that is responsible for those HDR images that most HDR haters get most upset about – those ones that look like someone poured psychedelic paint all over an otherwise perfectly lovely photograph.
it is a very powerful tool though, that lets you tweak an image to your heart’s content. If you’re looking for just one bit of software to use for your HDR workflow, then make it this one.
The Pro version is $99, whereas the cut down Essentials version is $39. Plugins are also available for Aperture and Lightroom, and the software works on both Mac and Windows. There is also a demo version that you can try out, which will just watermark your final image.
How to Do It – Taking the Shot
Shooting for HDR is easy, but there are a couple of things you need to remember.
Shoot in Aperture priority mode
Changing the aperture of a camera changes the depth of field of the shot – i.e. what is in focus and what isn’t. If you shoot in aperture priority mode, then the aperture will remain fixed, and the camera will vary the shutter speed in order to change the amount of light coming in.
If you don’t shoot in aperture priority mode, then the camera might vary the aperture between shots, and you will end up with three images of different exposures that also have varying depth of field. When you try and combine these, you will end up with a blurry mess.
Shoot at as low an ISO as possible
When there is less light available, we can adjust the ISO rating of our camera to let us continue to capture images at shutter speeds that won’t result in “shaky-cam” affairs.
Unfortunately, increasing the ISO of the camera results in increased noise in the image, which comes across as weird pixels, grain or artifacting in the image.
This can be edited out in software if it’s just one image, but when combining multiple images together such as in HDR, any flaws in the images will be multiplied together – so that noise can become a serious problem. The only way around this is to minimise the noise in the first place by shooting at as low an ISO rating as possible.
If you have a dusty sensor, you will also find that dust spots, particularly when shooting at higher apertures, can be very troublesome in HDR images. Shooting at lower apertures can help in these situations.
Consider the motion
Because you are shooting multiple exposures of the same image, if the scene you are capturing features a lot of motion then you might find that your end result features weird ghosts.
This can be partially solved by the use of anti-ghosting options in the HDR software; it is just worth considering when shooting for HDR.
Take the shot
That is essentially all you need to know to take your HDR image. Now you just need to put your camera in AEB mode, compose the shot, and press the shutter until all the exposures have been captured. Next comes the interesting part… the editing.
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How to Do It – the Editing Process
This is probably the bit you’ve been waiting for – how to turn those captured images into a final product. I’m going to use Photomatix for this example.
First, you need to load up your images into Photomatix. Photomatix accepts both RAW and processed images – RAW files are preferable if possible, but JPG will work in a pinch – and cause your computer less strain.
From Photomatix, choose Load Bracketed Photos.
Select the images you want to use and press “OK”.
The Preprocessing screen appears and tries to boggle you. If you were shooting handheld or you think your camera may have moved between shots, then you can have Photomatix attempt to align the images.
If there was a lot of movement in the scene, the Photomatix can also attempt to remove the resulting ghosting artifacts with the “remove ghosts” option.
Finally, press ok, and let the magic happen. This will take a bit of time, depending on how many images you are using and how powerful your computer is, before an excitingly-complicated screen like the following loads up:
Fear not, it’s not as complicated as it looks. Down the right hand side are a whole host of preset options, which you can choose from to get started. You can pick something that looks fairly natural, or something that looks completely insane, just by picking a preset that you like the look of.
Down the left hand side of the screen are a whole bunch of sliders and check boxes and other options that give you incredibly fine grained control over your final image.
My advice is to start off with a preset that you like the look of, and then adjust it to suit with the sliders – of which there are many.
Hovering your mouse over a slider will make some helper text appear in the bottom corner. There are a lot of options, and I would suggest playing with them all to see how they affect the outcome.
If you come up with a combination of sliders that you like, you can save it as your own preset, for use next time.
Once you are done with the editing you can press process to finalise your image, and then save it from the final screen.
Here are some examples of how the image I’ve been demonstrating with could be made to look using the built in Photomatix presets:
And so that is it for a quick (well, maybe not so quick) overview of HDR. Hopefully you found it useful! If you’ve got any questions, thoughts or opinions, please fire away in the comments below!