Digital Camera World » HDR

What is HDR? Everything you ever wanted to know about high dynamic range images

jmeyer — Sat, 02 Mar 2013 02:00:24 +0000

So what is HDR photography all about? In short, HDR techniques allow you to take pictures of high-contrast scenes and preserve all that important shadow and highlight detail. But it comes with a lot of jargon. Here we answer all the common questions about HDR images.

What does HDR stand for?
HDR stands for high dynamic range; and the abbreviation is often used in a longer form, HDRI – high dynamic range imaging. HDR is a form of photography that enables you to create a picture with a greater dynamic range than is usually possible.

To understand what it is and to appreciate its use, you first need to have a grasp of what dynamic range is all about.

So explain dynamic range to me
Dynamic range is a measure of the range of different light levels – from the darkest black to the brightest white – that can be recorded or displayed by a device. It defines the amount of contrast you can capture or show without losing detail at the extremes.

The dynamic range that can be captured with your SLR is greater than can be displayed on your monitor.

Why is this important?
Some scenes contain too much contrast for us to capture successfully with our cameras. We avoid taking pictures in the midday sunshine as our cameras can’t cope with the full range of light levels. Low-light scenes are another common problem area – we can expose successfully for the shadows, but not for the brightly-lit areas or vice versa.

Exposure for midtones

Are there ways around this?
Digital imaging has made it easier to resolve because we can see the result immediately and take remedial action. We can also use flash to help reduce contrast on a sunny day and use a graduated ND filter to balance the brightness difference between the sky and landscape.

What’s more, there are processing tricks we can use in Photoshop, particularly if we shoot in raw, that enable us to get information from the darkest and lightest parts of our pictures.

So where does HDR come in?
HDR enables us to shoehorn a greater range of brightness into an image in a way that a straightforward picture can’t achieve. A true HDR image is created from several shots of the same scene taken with slightly different exposures.

Each exposure captures part of the full tonal range. They are then combined into a single image with software. The trouble is that these true HDR images are hard to see…

What do you mean?
A true HDR image contains a far greater range of tones – too many, in fact, to be displayed on a normal computer monitor, or printed out on paper.

They are typically stored as 32-bit files – allowing 4.3 billion shades in each colour channel. By comparison, a standard JPEG image allows 256 (8-bit) shades per channel, and a raw file 4,000 (12-bit) to 16,000 (16-bit) shades per channel.

So what do you do with these very large files?
The next stage in most HDR images is tone mapping. Here the program uses the 32-bit HDR image to create an image with a contrast range that can be shown in print or on a monitor.

Each tonal value is remapped onto a scale that creates an image in which you can see detail in the brightest highlights and the darkest shadows, and without any clipping in these extreme areas of brightness. It’s this tonal mapping that creates the controversy with HDR.

Why the controversy?
Tonal mapping brightens shadows and darkens highlights, which slightly flattens the contrast of an image and increases edge definition.

But many HDR enthusiasts use the software to go further, creating an image in which all the detail can be seen clearly, but which no longer looks realistic. The effect is similar to that used in ‘hyper-real’ styles of painting. Some people like it, some don’t.

Exposure for shadows

What sort of software do I need?
There are lots of HDR programs available – including some free ones. The best known is Photomatix Pro, but the latest version of Photoshop (CS5) has a built-in HDR facility.

HDR programs usually have a range of sliders to help you control the tone-mapping effect to your own taste.

How do I take pictures in preparation for HDR effects?
Essentially, the process is the same as that used for bracketing. The number of shots you need is largely dependent on the actual tonal range of the scene you’re shooting. The more contrast, the more shots you need.

Three is the usual starting point, but you may need to take as many as nine, each with a one-to-two stop difference. Some SLRs have an AEB (automatic exposure bracketing) function, which will enable you to do this without too much fuss.

Exposure for highlights

What other settings should I use?
Your sequence of exposures should be as similar in content to each other as possible (although obviously, the brightness will vary). Any changes caused by movement can create a ghosting effect that the software will struggle with.

Set the focus manually, use a tripod, and set the exposure to aperture priority (so the depth of field remains constant). Set the camera to the fastest continuous drive setting available.

Is there an easier way?
Creating HDR images involves some effort at the time of shooting and processing but it’s relatively straightforward. However, there are easier ways.

A number of programs offer false HDR effects that can create realistic-looking HDR images from just a single picture. Similarly, a number of DSLRs and compacts now have built-in automatic HDR facilities that will take the sequence of pictures for you and compile them into your tone-mapped image in the camera itself.

Luminosity masks: why raw HDR is the best HDR

jmeyer — Tue, 27 Nov 2012 02:00:04 +0000

In the latest post of our ongoing Raw Tuesday series on editing raw format images we show you a luminosity mask technique that enables you to create the perfect raw HDR image by blending two exposures according to lightness, not just area. This is a variation on the traditional HDR photography technique, but because we want to darken highlights and lighten shadows throughout the image rather than in selected areas, we’ll blend the images in a different way.

01 Create a well-exposed sky
To create a version of the image with a well-exposed sky, we’ve reduced Exposure to -0.40. Now we can open the edited image in Photoshop/Elements or save a copy before producing a second edit. By reopening the original file in Adobe Camera Raw if need be, and increasing Exposure to +2 and dropping Blacks to 2 or 3, we can produce the foreground exposure – you can go back later and try different Adobe Camera Raw settings at this stage if you like.

02 Rename the images
Now we can open this second edit in Photoshop/Elements (if we’d saved the edits out of Adobe Camera Raw, we’d open both from our desktop). We should also rename the images ‘sky1’ and ‘foreground1’ in case we want to produce more raw edits (bear in mind that if we tried this using a raw file in Elements, we wouldn’t be able to open the RAW file again unless we renamed the second version).

03 Combine the sky and foreground
Using the sky image, we Select All and Copy. Then on the shadows image, we Paste the sky image into the foreground document as a new layer. (In Elements, we’d see a bit-depth warning if the images were in 16-bit mode; you’d OK this to convert to 8-bit). The new layer is renamed ‘sky’ so we don’t get confused about which layer is which.

04 Make the selection
Now it’s time to create the luminosity selection that we’ll use to blend the two images. If we were using Photoshop Elements, we’d skip to steps 6 and 7 at this point. Using Adobe Photoshop though, we open the Channels palette and [Ctrl]/[Command]-click on the RGB channel. This action generates a selection of the sky layer’s highlights and light midtones.

05 Photoshop: Add the mask
With this selection active, we click the ‘Add layer mask’ button at the foot of the Layers palette. The layer mask will be based on the luminosity selection that we’ve just generated: the selected highlight areas of the upper layer will be revealed and its dark areas will be hidden, revealing the correctly-exposed shadow areas on the Background layer, which is the shadows image.

06 Elements: Create the mask
To create a luminosity mask in Elements, click the sky layer thumbnail and select Select All and Copy. Next, add a Levels adjustment layer, and OK the dialog without touching the sliders (from Elements 8, this will be the Adjustments panel rather than a dialog). To display the mask in the main image window, [Alt]/[Option]-click the mask thumbnail and paste the copied sky image.

07 Elements: Create a clipping mask
A grayscale version of the sky layer is now visible; the mask will be based on those grayscale values. A quick [Alt]/[Option]-click on the mask thumbnail enables us to view the image again. To apply the mask to the sky layer, we move the Levels layer beneath the sky layer in the stack, then [Alt]/[Option]-click the line between the two layers to create a clipping mask.

PAGE 1: How to get the raw HDR look with luminosity masks
PAGE 2: Common questions about raw HDR and luminosity masking

Fake HDR effects in Photoshop Elements

jmeyer — Thu, 22 Nov 2012 11:30:18 +0000

Some photographers employ the processing powers of packages like Photoshop CS5 or Photomatix to bracketing exposures to combine into a single composite high dyanmic range image that reveals fine detail in the shadows, midtones and highlights. HDR photography editing techniques add rich (and sometimes false) colours that enhance the artistic look of a shot,  and many even like the way the HDR process can add artefacts such as halos around object edges.

If you’re an Elements user then you’ll lack access to more sophisticated commands like Photoshop CS5’s Merge to HDR Pro, but you can still endow your compositions with typical HDR properties from within Elements.

The trick to getting the HDR look is to shoot a series of bracketed exposures. Here, we’ll show you how to process multiple raw format files to reveal specific tonal details and then use the standard Elements Photomerge command to combine them into a single image packed with detail.

We’ll then show you how to add typical HDR artefacts using the Unsharp Mask command. This will also claw back missing midtones, so that delicate details such as the engravings on our shot can be read more easily.

Step by step how to fake HDR effects in Elements

01 Reveal the wood texture
Open your bracketed exposures in the Camera Raw editor. Click on the hdr_before_02 thumbnail and drag Exposure to -0.45. Boost the Blacks to 21. Increase Contrast to +91 and Clarity to +83 to make the wood grain stand out.

02 Enhance tonal detail
Click on your first image and increase Exposure to +2.45 to reveal midtone and highlight detail. Increase Contrast to +37 and push Clarity up to +41. On your third image, set Exposure to -2.55 to reveal more shadow detail. Click Select All, then Open Images.

03 Use Photomerge
Go to File>New>Photomerge Exposure to merge the shots. Click Open All, then tick Smart Blending. Drag the Highlight Details slider to 73 to darken the brightest areas. Drag Shadows to 70 to lighten the shadows. Increase Saturation to 17 and click Done.

04 Try Unsharp Mask
Photomerge blends the shots together and displays the composite image as a new layer.  Go to Enhance>Unsharp Mask. Set Amount to 87% to reveal the engraved text. Set Radius to 40 to spread the contrast change and create a hint of a halo. Click OK.

05 Tweak the Levels
Choose Layer>New Adjustment Layer>Levels. Set the grey slider to 1.29 to lighten the midtones. Grab the Brush tool. Set Opacity to 100% and the foreground colour to black. Click on the white mask. Spray over the engraving to stop it being lightened.

06 Burn the wood
Choose Layer>Flatten Image. Grab the Burn tool and set Range to Shadows. Set Exposure to 20%. Spray over the grain and knots in the wood to darken them and reveal their texture. Add a Hue/Saturation Adjustment Layer and up Cyans Saturation to +14.

HDR Photography: set up and process your first high dynamic range image

jmeyer — Tue, 20 Nov 2012 11:30:12 +0000

Capturing a scene with a full range of tones is one of the biggest challenges faced by everyone from amateur to professional photographers. Our tutorial on HDR photography shows you subtle ways around this common photography problem by learning how to set up, shoot and process a high dynamic range image. Even if it isn’t your first time practicing HDR photography, we’re confident you’ll learn something new.

One of the limitations of digital camera sensors is that they simply cannot record detail in both the shadows and highlights in high-contrast conditions. You’ll frequently encounter this sort of situation shooting outdoors on bright days, or when you’re photographing interiors or night photography scenes.

Landscape photographers typically resolve this by using graduated filters to balance the exposure between the land and the sky. However, there are limitations with this.

Not only are the filters expensive, they are fiddly to use, and the technique relies on a straight horizon for the best results as there’s no way to mask out a lone tree or standing stone that breaks through the horizon.

However, there is another solution. You can take several pictures at different exposures and combine them in the digital darkroom to create an image with an expanded range of tones. This is known as a High Dynamic Range image – better known as HDR photography.

Shooting HDR photography is not as complicated as it sounds. All you need to do is take a sequence of images by bracketing at different exposures, from underexposed to overexposed. How many images you need and what the difference in exposure between shots should be largely depends on what you’re photographing.

Here’s how to make a high dynamic range image.

HDR photography step by step

01 Keep it steady
As you’ll be combining multiple shots to make your final image, the composition needs to be exactly the same in each photo. This means a sturdy tripod is vital. You’ll also need to take steps to avoid any camera movement between shots, so use a cable release so you don’t have to touch the camera at all during the process.

02 Camera settings
Your aperture has to remain constant throughout the sequence, otherwise the depth of field will change between shots and this will make aligning them more of a challenge. So, switch to your digital camera’s A, or aperture-priority mode. Now the camera will vary the exposure by changing only the shutter speed. We used an aperture of f/11.

03 How many shots?
In most cases, three to five images with a one- or two-stop difference between one shot and the next is enough for constructing an HDR image, but if the scene has a very wide brightness range you may need to shoot five or seven frames. Most HDR software can process NEF files, so set image quality to raw format for the best results.

04 Auto Bracket
Activate your camera’s auto bracket feature. This will calculate and adjust the exposures in your sequence. There are two settings. One is the number of shots – three is the normal number, but some cameras let you shoot five. The second setting is the interval between the shots. This can be 1EV, 2EV or, on some cameras, 3EV.

05 Continuous mode
Now set your camera to the continuous shooting mode. If you have a choice of speeds, pick the fastest available. This will minimise any cloud and tree movement between each shot which can cause nasty ‘ghosting’. You’ll now be able to take all the shots you need for the HDR sequence without touching the camera.

06 Test shots
Take some test shots before starting. The longest exposure should show detail in the darkest areas, such as the shadows, while the shortest exposure should show detail in the brightest ones, such as the sky. Use the histogram to assess exposure. Our scene had a medium to high brightness range, so we took three shots at intervals of 2EV.

07 Get HDR software
Download the free 15-day trial version of HDR Efex Pro 2 from Nik Software. We’ve installed it as a plug-in to Photoshop CS5. Browse to your images in Adobe Bridge and select the five raw files. Go to Tools>Nik Software>Merge to HDR Efex Pro. Your images should open in the HDR Efex Pro window. This can take several minutes.

08 Blend your shots
You’ll notice presets on the left panel of the HDR Efex Pro window. These are especially handy if you’re new to this technique. We used the Realistic Strong preset. These settings can be further refined using the sliders in the panel on the right side. We applied these settings: Stricture 48%, Blacks -44%, HDR Method Clean and Method Strength 35%.

Bracketing explained: what you need to know about maximising detail

jmeyer — Tue, 13 Nov 2012 16:15:28 +0000

Whatever subject you shoot, capturing detail is fundamental. And bracketing your exposures is one of the best and easiest ways to ensure you can produce images with a high dynamic range and bags of detail. A staple on lists of photography tips all over the internet, getting in the routine of bracketing photos will put you in good position for making images of the highest quality.

Below we’ve answered some of the most common questions about bracketing, as well as explained step-by-step how to bracket exposures and explained the principles of dynamic range and exposure blending.

Image by Adam Burton

Bracketing – that’s when you take multiple pictures that are slightly brighter and slightly darker than a normal shot, isn’t it?

Yes, that’s right. Bracketing involves taking a sequence of pictures of the same scene at a range of exposure settings. There are two reasons you might want to do this; as a safety net to ensure you get at least one well-exposed picture of the scene (as camera exposure meters don’t always get it right first time), or to give you a range of exposures that you can blend together later in software.

Why would I want to spend time blending images together? That sounds like far too much hassle!

The digital sensors in today’s cameras have a limited ‘dynamic range’. This means that they are only capable of capturing fine detail within a certain range of brightness levels.

The exposure that’s set at the time of shooting forms the mid-point of this range, and the camera can record detail either side of this, in areas  that are slightly brighter or darker than this ‘middle’ setting.

Dynamic range can be measured in stops. For instance, if a camera offers nine stops of dynamic range, it means it can record detail in areas of a picture that are up to four stops brighter and up to four stops darker than the set exposure.

The contrast – or the difference between the darkest and brightest parts – of a scene will often fall within the camera sensor’s dynamic range, which means you can record detail in all areas in a single shot.

However, high-contrast scenes may exceed the camera’s dynamic range, so you may end up with a picture  that holds no detail in shady areas or bright areas – or either.

For example, when you photograph a dark building backlit against a very bright sky the difference in brightness between the deepest shadows on the building to the brightest highlights in the sky may be 12 stops.

This is likely to exceed your camera’s dynamic range, so it won’t be able to record detail in all of the areas of the picture in one attempt.

As a result, you may find that you end up with a picture where the shadows are actually too bright, or the highlights are too dark. This will depend on the ‘middle’ exposure setting that’s selected by you, or automatically by the camera.

To get around this limitation, you can try taking a whole sequence of shots at different exposures –  from a short exposure that under-exposes the shadows (but ensures that the highlights aren’t burnt out), through to a long exposure that reveals the detail in the shadows (but over-exposes the highlights).

The well-exposed parts of each of your sequence of shots can then be combined in Photoshop or similar software to create a high dynamic range (HDR) image.

OK, so what’s the best way to go about bracketing a shot?

You can manually bracket a shot, or let the camera do it automatically. To manually bracket a series of images, set the camera to either Aperture Priority, Shutter Priority or Manual shooting modes, because these modes give you the most control.

If you’re working in the first two modes, you can simply take your shot as normal, then use your camera’s Exposure Compensation function (press and hold the ‘+/-’ button) to take another shot that’s brighter  (by dialling in a ‘+’ value) and one that’s darker (by dialling in a ‘-’ value).

The amount of compensation you need to dial in will depend on the scene and lighting conditions, and of course the final effect that you’re trying to achieve. Try 2/3 or one stop either way to begin with.

In Manual mode, you can just adjust either the aperture or the shutter speed in order to give you  a brighter or darker image.

In this high-contrast scene, the shadows and highlights are being ‘clipped’ at the edge of the histogram, so the image will be detail free in these areas.

So, if I use automatic bracketing the camera will do this for me?

It will, although you’ll need to tell it how much you want to bracket a shot. Your DSLR’s Auto Exposure Bracketing (AEB) function can be found in the camera’s shooting menu.

This lets you dial in the strength of the bracketing, which is usually up to three stops brighter or darker than the set exposure, in 1/3 stop increments.

With AEB activated and your camera’s drive mode set to continuous shooting, the camera will automatically capture three or more different exposures when you hold down the shutter release.

Are there any situations where Auto Exposure Bracketing won’t work?

Yes there are. AEB might not be an option when you’re photographing fast-moving subjects, such as motor racing or flying birds. There might only be one frame that captures the peak of the action, and this might  not correspond with what you consider the ‘best’ bracketed exposure.

You also need to be aware of any moving elements in a scene if you’re planning on taking a range of exposures to blend together later in software, because this can make it a little trickier to blend the shots.

Likewise, you need to avoid changing the aperture if you’re planning on combining frames, because this will change the depth of field (how much of the picture appears in sharp focus).

Finally, always make sure you use the camera in Aperture Priority mode when you activate Auto Exposure Bracketing, because this lets you lock the aperture value in.

PAGE 1: Common questions about bracketing
PAGE 2: How to start bracketing exposures
PAGE 3: Understanding dynamic range
PAGE 4: Try exposure blending

Vertorama Tutorial: make enormous landscapes with extra impact

jmeyer — Sun, 14 Oct 2012 03:00:29 +0000

Follow our simple steps below and learn how to stitch two photos together to create a vertorama image, or vertical panorama, which gives you the best possible image quality in your landscape photos.

One way of creating a square image is to take two rectangular photos with the aim of stitching them together afterwards. This is easiest if you have a tilt-shift lens because you can use the shift movements to take two photos that align perfectly.

But you can also do it with regular lenses, as long as you’re prepared to do some Photoshop work and crop the blended photos to a square.

This technique works well with subjects such as seascapes where it’s easy to merge the photos at a point where the join is easily hidden – either in the sea or in the sky.

It also has the benefit of giving you a larger image to work with, because it’s made from a combination of two files. This is useful if you intend to make large prints, or if you have an older camera with a relatively low megapixel count.

I created the square photo here by joining two rectangular images together. I mounted the camera on a tripod, took one photo, then swivelled the camera upwards leaving a little overlap, and took another. It was then fairly simple to merge the two together in Photoshop.

This type of image is called a vertical panorama – or vertorama. Search for this term on Flickr to see plenty of examples.

An advantage of this technique is that you can take two images with different exposure settings, one for the land and one for the sky, and combine them to get the best possible image quality in both areas – another reason why vertoramas are ideal for landscape photography.

The photo on this page is a good example of this principle. We exposed the bottom photo for the land, and the top one for the sky, then processed the raw files in Adobe Camera Raw (ACR) to get two matching images. I did this by keeping all the settings the same, such as the white balance and contrast, except for exposure, which I adjusted individually for each image so they matched. Then it’s just a matter of aligning the two images in Photoshop, tweaking the Levels, and merging them.

01 Open and align
On the first image, go to Image>Canvas Size and double the height, keeping the photo anchored to the bottom. Copy and paste the second image onto the first, aligning with the Move tool.

02 Make a selection
Select the Rectangular Marquee tool and draw a rectangle across the join. Go to Select>Refine Edge. Set Smooth to 100 and Feather to around 150. Press OK when you’re done.

03 Blend the images
Go to Select>Inverse. Click the Add layer mask icon to create a new Layer Mask. Adjust the Levels and colour balance to get a get a good match between the images. Finish by cropping to a square.

Behind the image: how pro photographer David Clapp fought the fog… and won

jmeyer — Sat, 15 Sep 2012 06:00:45 +0000

In a new series of weekend guest blogs on Digital Camera World, professional travel and landscape photographer David Clapp will be sharing the stories behind how he made some of his favourite images. Sometimes it will be how he processed a photo; other times it will be how he simply got to his location in one piece! In his first post, the Getty contributor tells us how a challenging sunny, yet foggy, morning in Devon made getting a good exposure a real challenge.

You can follow David on Facebook or Twitter, or keep up with his work on his wonderful photo blog.

The first week of September has been a rather misty one to say the least. After a moonlight photography session on Dartmoor became a raging success, I was out for another round the following morning.

Still rather sleep deprived I headed to Haldon Forest near Exeter to make the most of yet another foggy start.

This is a favourite Devon view point of mine, looking down over the gentle countryside over Mamhead towards the Exe Estuary.

It’s problematic to say the least – too much fog and its a write-off, too little and it can be a rather unrewarding. On that morning, the fog enveloped the countryside beneath, but as the sun rose, the golden light lit the incredible mist and trees in front.

Camera Setup
I used my trusty 1Ds3 for this image matched with a Contax 35-70 f3.4 lens, mounted on a Gitzo 5540 6x tripod. There was literally no wind whatsoever, which made life a lot easier.

I knew the image would become a digital blend of multiple exposures so there would be no ghosting between exposures, a common problem when shooting high contrast scenes from multiple images.

Processing – and it’s an HDR
Would you be surprised to tell you that this is an HDR? It’s made of nine images, an Auto Exposure Bracket, +2 0 -2. There are three landscape format compositions stitched together.

Although my original idea was to process the entire batch in PTGui, (which can fuse images and stitch together as well) the initial results were rather unappealing and lacked warmth and colour.

I processed each part identically using Photomatix (Details Enhancer), making sure the image parameters were identical, as finally stitched the three blended parts together using PTGui.

Final Touches
Additional masking was done to subtly enhance light and colour, as well as slight soft focus effects to the trees. I also had my work cut out removing a rather large airplane contrail, which was removed using the patch tool and then subtly blurred to cover my tracks.

Although a complicated shot to assemble, it all looks very natural, but I have to say, it think this was mostly down to the great September weather. Long may it last.

Dynamic Range: what you need to know about capturing all the tones in a scene

jmeyer — Wed, 12 Sep 2012 01:00:09 +0000

If you’ve ever taken a shot in sunlight, or any other situation where the brightness range is high, the chances are your camera will have lost some detail in the darkest parts of the picture, the brightest parts or both. It’s one of the most common photography problems you’ll encounter, but it isn’t to do with exposure. It’s because the difference between the brightest and darkest areas, or ‘dynamic range’, is so great that you can’t find a single exposure that can capture them both.

Digital camera sensors can capture a wide range of brightness values, but there is a limit. If you’re faced with a scene that has a wider dynamic range (or brightness range) than the camera’s, you may well have a problem. In this article we’ll offer some of our best camera tips and expert advice for recognising, measuring and overcoming this problem.

How do you check dynamic range?

Your camera’s histogram display is a good way to check if there’s a problem (learn more about how to read a histogram).

If the histogram is chopped off, or ‘clipped’ at the left-hand end of the scale, it means that some of the darkest parts of the picture haven’t recorded and will appear as a solid black.

If the histogram is chopped of at the right-hand end, it means the brightest parts of the picture have been overexposed and will reproduce as a solid white.

Quite often, you can adjust the exposure, re-shoot and solve the problem. But scenes with a very wide brightness range also produce a very wide histogram – and sometimes the histogram is so wide that it’s clipped at one end or the other, no matter how you adjust the exposure.

The range of tones on an overcast day is quite narrow, producing a narrow histogram. This won’t pose any exposure problems. But the extreme brightness range of a sunny day may produce a histogram so wide that it won’t fit within the camera’s dynamic range no matter what you do.

What’s the answer?

The histogram shows you the range of tones in the whole picture, but not necessarily the ones which you’re most interested in! Sometimes it’s okay to have dense areas of black. It’s fine, for example, in black and white photography.

So by all means use the histogram as a guide, but consider checking key areas of the picture yourself. You can do this using your camera’s spot metering mode to check the brightest and darkest key areas in the picture to see if there’s a single exposure which can capture them both.

Alternatively, you can shoot raw files. These capture up to 1EV of extra shadow and highlight detail that you can extract later in your raw conversion software. You won’t see any sign of this on the camera histogram, though, because your camera will display a processed JPEG preview of your image for display on the LCD, even if you’ve shot in the raw format.

You still have to get the exposure exactly right, even if you shoot raw, but the slight extra leeway might be all you need to capture extremely dark and bright tones in the image.

Sometimes, though, even shooting raw files won’t be enough, and this is where you enter the world of HDR…

PAGE 1: Checking key areas of your picture
PAGE 2: High Dynamic Range techniques
PAGE 3: Scenes that cause problems for dynamic range
PAGE 4: How to measure dynamic range

Get the HDR effect from one image

jmeyer — Wed, 15 Aug 2012 11:23:57 +0000

When you’re faced with a subject that has a high dynamic range – that is, one that has high contrast, with both very bright highlights and very dark shadows – one technique you can use to capture the full tonal range is high dynamic range imaging. But as you will see in our Photoshop tutorial below, there is a simple way to get an HDR effect from just one raw format picture.

To produce an HDR effect, you typically shoot a range of bracketed exposures (find out how to use your camera’s auto-exposure bracketing) to capture detail across the tonal range, and if you want the image to retain the utmost quality then this is the best way to do it.

But while HDR is great for landscapes and cityscapes, you can’t use the technique for sports or other action shots, because if there’s any movement between exposures you won’t be able to align and blend the images effectively.

However, it is possible to produce an HDR effect from a single raw file, by producing three different versions of the same image – one ‘standard’ exposure, one ‘under’ and one ‘over’ – and then merging these images using HDR software.

For this tutorial we’re using Photoshop’s Merge to HDR Pro command, but you can get similar results with dedicated HDR software such as Photomatix Pro.

Click here to see step-by-step how to create an HDR effect from just one picture.

Truthful Tone Mapping: a quick guide to realistic HDR in Photomatix Pro

jmeyer — Tue, 05 Jun 2012 05:00:30 +0000

High dynamic range (HDR) is something photographers either love or hate. We love it! You can use it to create some extremely dynamic, surreal images and push the look to its limits. There are many bad examples of HDR out there where extreme tone mapping in Photomatix has left images overcooked and overdone. But when you aim for realistic HDR and your images aren’t pushed to extremes, it’s a technique that can really help you in difficult lighting conditions.

The strength of the HDR ‘look’ depends on the image. Some cry out for a strong, bold, unmistakable HDR approach, while others require a gentle realistic HDR look that you wouldn’t even know was HDR. Photomatix Pro’s Tone Mapping – Details Enhancer does exactly what it says on the tin, making every fleck of rust or faded colour really jump out in our sample image for a hyper-real look.

When taking your own HDR images, put your camera on a tripod and use manual settings for everything, including focus, white balance and exposure. Bracket the exposure with the shutter speed only, at -2 stops, normal exposure and +2 stops. In very high-contrast conditions, such as indoors with windows, you’ll need more bracketed images to handle the exposure range (find out how to use your camera’s auto exposure bracketing to conquer high contrast).

We found this wrecked boat on a beach in California. The sun was shining so the light reflecting off the white side of the wreck made a normal image impossible. It’s ideal for some fun in Photomatix Pro, so let’s get going!

Step 1: Check out the default
Download, install and start Photomatix Pro (see Super Tip!, right). In Workflow Shortcuts on the top left of your screen, check Load Bracketed Photos. Next click Browse and open photomatix1_start.tif, photomatix2_start.tif and photomatix3_start.tif and click OK. Uncheck Align Source Images and Remove Ghosts, then click OK again. On the Tone Mapping Adjustments page, click the first Preset.

Step 2: Build a custom preset
Play around with the Preset thumbnails for a while. Look at overblown Grunge and cool B&W. Then choose the thumbnail for Enhancer – Default, because it’s a great starting point. Although you could happily go with it, you want to create a strong look here, so put Strength and Colour Saturation up to 90. Jump down to Gamma and set it to 1.30. Then go back to Luminosity and set that to 6.0 and Detail Contrast to 1.0. Tick Lighting Effects Mode and select Medium.

Step 3: Move on down
Smooth Highlights to 30 and set White Point and Black Point to 0.010%. Set Shadows Smoothness to 10, but leave all the other controls as they are. It’s all very heavy-handed, so a halo is just visible around the boat, but it’s not too objectionable. Click Process, then File>SaveAs, and make sure that TIFF 8 bit is selected in the window before you save it. Next close Photomatix Pro, fire up Photoshop Elements, and load your new image.

Step 4: Remove haloing
In Enhance>AdjustLighting>Shadows/Highlights set 10%, 10% and +20%. In Enhance>Adjust Lighting>Levels, move the midtone slider to 1.15. In Filter>CorrectCamera>Distortion move the Vignette to -30. With the Burn tool at 100 pixels, change the Range to Midtones at 9% and go around the boat to remove the halo. Get rid of sensor spots in the sky with the Spot Healing brush, using the Content-Aware type.