HDR Tutorial: How to use a tripod

Sutherland Backyard  

This street scene is from Sutherland in the Northern Cape of South Africa. It's a small town in the arid Karoo area and is well known for being the coldest town in the country, and home to the South African Astronomical Observatory. It was very cold when I was walking around, with a bitter wind, and the place felt absolutely deserted.

Most of the town is built from local stone, like you see here, with typically unpainted corrugated iron roofs. It doesn't rain much, so the roofs don't need painting.

 

On to this week's installment of the HDR tutorial, which is ...

How to use a tripod
Someone I once worked with always used to talk about 'back in the day'. Well, back in the day cameras were huge wooden boxes and really, really heavy. Exposures were seriously long, and you had to have a tripod to keep it all steady, no question about it.
Of course now we have the camera equivalent of Moore's Law, where things just keep getting smaller and smaller, and lighter and lighter, and tripods aren't needed for most things.
But here's the thing. To take HDR effectively you need a tripod. It's heavy, it's cumbersome, it's a pain, but you need to do it. You can take a hand held bracket set, sure, and I'll cover that in another tutorial, but the results are not going to be consistent. If you want to take high quality HDR images you need to suck it up and carry a tripod.
You are using a tripod for two reasons when you HDR:
  • Firstly, you will often be using very slow shutter speeds, especially on your +2 image. It will be too slow to hand hold except on very sunny days. A blurry image will not work on HDR, so using a tripod will solve that problem.
  • Secondly, you need to align all your images later in your HDR software, and a tripod will ensure that all your images start life perfectly aligned.
Even using a tripod doesn't instantly solve all your HDR woes. You will still need to be very careful to keep things as steady as possible, because even a tripod can move or transmit vibrations. I found that getting used to a tripod was quite a frustrating experience, and one that took quite a bit of fiddling and practice before I got it right.
So without further ado, here are my tripod tips, all learned from bitter experience:
  • Get a good, stable tripod. Stable unfortunately means heavy, because a tripod derives a lot of its stability from its weight. I use a basic version of the Manfrotto 055 which is a classic design and is tried and tested. It has served me very well so far. As far as the head goes, I find a ball head the most practical head to use. It lets me move my camera around quickly and easily, and it locks as quickly and easily. Mine is a Manfrotto 498RC2. I have seen other photographers recommend the Really Right Stuff and Gitzo brands, but they aren't available at the bottom of Africa, where I live. A good tripod is expensive, but it should last you many years, if not decades, so don't scrimp on it. While you're at it, get a good bag with a shoulder strap for it as well. Your shoulder will thank you.
  • Frame your shot first. Before you set up your tripod, find the shot you want by hand holding your camera. Once you have a tripod attached it becomes tempting just to set up the first, most obvious shot you see. Use the freedom of no tripod to find the image you want, then set up the tripod afterwards. If you ever see me shooting with a tripod then you will often see me breaking this rule by hand holding the tripod with the tripod still attached. Now that is unwieldy!
  • Batten down the hatches. When using your tripod check that every possible connector and screw and knob is tightened as much as possible. Check the tripod mounting plate that stays connected under your camera body as well. Just one loose bit can lead to a wobbly camera and a blurry photo.
  • Keep the tripod as low as possible. Set up lower for more stability, especially if it's windy. The longer the legs are extended the more unstable the setup will be. Try not to extend the central pillar either, as it's quite wobbly when extended. Obviously, if the picture you want demands that the tripod be fully extended, then do so, but be super careful about movement.
  • Hang heavy stuff from the tripod. Because a tripod derives a lot of its stability from its weight, you can increase that stability by increasing its weight. Most tripods have a hook near or under the central column that you can use for doing this. Pack a collapsable shopping bag in your camera kit for this purpose,  and use the bag and the hook to temporarily hang whatever heavy stuff you can find from your tripod. Or just keep a carabiner attached to your camera bag and hang it from the tripod.
  • Check the ground conditions. Set up your tripod on a hard surface, and push down firmly on the tripod to ensure the legs are fully splayed out and seated well on the ground. If the ground is soft, make sure you push the tripod in until it's seated securely, or find some rocks to seat the legs on.
  • Shoot in mirror up mode. You need to make sure that just like your tripod is as vibration free as possible, so is your camera. The first thing to do is put your camera in mirror up mode. That way the mirror flips up before you take the shot. The idea is to flip up the mirror, wait a few seconds for any vibrations to stop, then take the picture.
  • Turn off VR mode. That's Nikon talk for Vibration Reduction. The Canon equivalent is IS or Image Stabilisation. These modes reduce shake in your lens while you are hand holding your camera. They work by the lens generating its own vibration with little electromagnets inside itself. This vibration is used to cancel out the vibration caused when you hand hold your lens. The bad news is that if you are not hand holding (for example, you are using a tripod), the vibration made by your VR system can actually cause your picture to blur. I often leave it on by mistake, and it usually seems OK, but the manufacturers recommend you tun it off when using a tripod, so it's best to try and remember.
  • Use a remote. My Nikon comes with a nifty little infrared remote so you can trigger your camera without touching it. If you are taking exposures with a remote, your eye will be away from the eyepiece. In that case you should cover up the eyepiece with the little cover that was provided with your camera. Otherwise light will get into your camera that way, and could confuse your camera's exposure readings. If your head isn't blocking the eyepiece while you are taking exposure readings, then the cover should be on. I don't usually bother, but bear it in mind if your exposures are looking wrong.
  • Use auto bracketing. Try and use auto bracketing on your camera, so you don't have to touch your setup at all while making your entire bracket set. If you do need to manually change your exposure settings, then do so with an incredibly light touch. This will usually be the case when making a bracket set of more than three exposures.
  • Sometimes things move anyway. Even when I use a tripod, I sometimes get a small amount of movement. Maybe my tripod was set up on sand, and it moved a fraction, or the wind was blowing and the tripod shook. But not to fear, because Photoshop has a very nifty aligning feature. Aligning your images will be far better and more successful if you had slight movement on a tripod, rather than the far bigger movement you will get from hand holding. Its also better movement, because it can only be in a very limited range and you won't get the potential parallax shifts that hand holding gives (which may not be correctable in Photoshop at all).
  • Don't trip people. Tripods are clumsy so be careful and aware of people around you. Broken hips aren't cool.
  • Be careful of mugging. If you get totally wrapped up in your tripod setting up and HDR settings, you are a potential mugging victim, so again be aware of what's going on around you. A tripod makes a great weapon though, if you get into trouble. Try and cultivate a psychotic stare to go with it.

Unfortunately, as useful as tripods are, there are many times you just can't use them. Many museums or historical sites have banned tripods, so you may have to hand yours in at the door. Whether they are worried about you tripping people up, or damaging historic floors, or you just look like a professional photographer who will be competing with them in the postcard business, as soon as your tripod goes through the metal detector at the front door, it will be singled out and sent to jail until you leave the premises. Even in places other than museums, watch out for security guards. They really don't seem to like tripods, and get especially tetchy about them around airports and the like, as if photography was some terribly subversive pursuit.

That's when you'll need to hand hold. And that's the subject for next week's tutorial.

Going for gold in Istanbul

Interior View of the Mustafa Pasha Pavillion at Topkapi Palace, Istanbul  

This is the Mustafa Pasha or Terrace Pavillion at the amazing Topkapi Palace in Istanbul, Turkey. It also seems to be known as the Sofa Pavillion, and the word Kiosk is often used in place of Pavillion. Little know fact: the work kiosk comes from the Turkish köşk, meaning pavillion. Neat.

Topkapi Palace was the main residence of the Sultans of the Ottoman Empire from the mid-1400s to mid-1800s or so. It became a museum in the 1920s when Turkey became a new state. It's a huge complex with a large amount of impressive and well-preserved Ottoman architecture.

This particular room was built in the Rococo style in the 1750s to give the Sultan of the day and his friends a comfy viewing spot for the events in the gardens below. Probably on their sofas, hence the one name of the room. Or on their ottomans, perhaps? Ottomans on sofas? This view gives a good idea of the opulence of the palace. I don't think they believed you could overdo gold.

 

HDR Stuff

I was glad that this shot worked out well. The  room was closed to the public, and I could only get to view it through the windows from outside. Tripods were banned in the palace complex. I held the camera steady against the glass and set the shooting speed to high for a fairly well aligned handheld HDR bracket set of three (-2, 0, +2).

This is also for me a rare example of processing with Nik Software's HDR Efex Pro. I quite like the software, but don't find it as intuitive to use as Photomatix Pro. HDR Efex Pro has the cool feature of control points, which allow you to set a point on the photo from which you can set the amount of exposure level or saturation or sharpness or whatever in a certain radius from the point, and it auto-detects edges to contain its effect. It seems to do a good job of it, but often feels a bit fiddly to me. It is on my agenda to fiddle with more though, because it feels pretty powerful, and I'm sure there are some very good effects to be had, pun not intended.

HDR Tutorial: Bracketing

Muizenberg beach huts  

Muizenberg Beach in Cape Town has a very pretty collection of beach huts for changing in. I don't think I've ever actually changed in them, but I have photographed them often. Lurking around change rooms with a camera is probably not a terribly bright idea, come to think of it.

This was photographed at dawn, so no-one was near the huts. I was very surprised to see one family swimming already and there were several joggers around. It's hard enough to get up this early to photograph, so I don't know how you do it for exercise. I think the HDR technique does a good job of bringing out the texture in the weathered timber.

 

This week I continue with part four of my HDR Tutorial series by looking at an essential part of capturing an HDR image, bracketing.

What is bracketing?

Once upon a time, in the days of film photography, photographers didn't have the benefit of being able to preview a shot immediately after taking it, like we can on our funky little LCD screens. Which means they didn't do that amusing thing we do where we squint at the back of our cameras every single shot. But it also means they couldn't be sure they were getting the shot right until they had developed their film.

To make sure they had a better chance of getting their camera settings correct for difficult shots, they developed a technique called bracketing. The idea was to shoot a range of images of the same scene while just varying the one setting that was uncertain. For example, if you weren't sure of the exposure settings for a scene, you would take several shots with different exposure settings, adding to the the most likely setting with ones that were likely to be a little under- and overexposed. You would end up with a sequence of shots from too dark to too light, with hopefully an ideal one somewhere in the middle. This is a bracket set. The problem is that in difficult lighting situations there often isn't just one ideal exposure, even if you shoot a bracket set. Fortunately, now we don't need to choose one shot anymore, we can take them all and combine them into one HDR image.

You can use the concept of bracketing for other settings on your camera too, such as white balance or depth of field, but for the purposes of HDR we are just interested in exposure bracketing. The whole point of HDR is to extend the dynamic range of a single image, so we deliberately shoot a range of exposures from too dark through to too light, and let the software sort it out.

How many shots should I have in my bracket set?
Before you can set up a bracket set on your camera you need to decide how that set will be made up.
The convention of a bracket exposure set is that it's usually three, five, seven, or sometimes even more shots, with the middle one being the normal exposure you would have taken. From the normal middle shot, you vary the exposure up and down by a fixed amount, usually by an Exposure Value (EV) of 1 or 2 EV. The middle exposure is called '0' because it has zero deviation from the normal settings. An exposure underexposed by 2 EV is called '-2'. Likewise, an exposure overexposed by 2 EV is called '+2'. A simple bracket set could then be referred to as -2, 0, +2.
Deciding what bracket set to shoot for HDR is a topic of much debate and personal preference. I have found that for 90% of my HDR images, I can get the results I want with a -2, 0, +2 set. It's a matter of choice, but for starting out I would recommend you keep it simple and shoot your images with a bracket set like this. It's important to remember that you want to change your exposure by changing your shutter speed, not your aperture, so make sure you are set to Aperture Priority mode. If you change your aperture with each shot, all your shots will have different depths of field, which will be hard to combine later.
I increase the size of the set for shots with trickier lighting. So for a dimly-lit interior scene with windows looking onto a bright exterior, I would probably shoot a -4,- 2, 0, +2, +4 set. The most hardcore lighting is shooting directly into the sun, say for a sunset, and in that case I would consider an even bigger range. On trickier shots, I also sometimes use a 1 EV spacing in the set, so that the HDR software has an even greater range of exposures to work from. I don't find that making a huge difference, so I wouldn't recommend that while starting out.
Something to think about though. You've come all this way to take this photograph, you've taken the time to set up your tripod, you won't be here again for a long while, so why scrimp on your bracket set? Shoot more than you need, you can always delete the ones you don't want later. Not that I'm very good at deleting anything. But I'd rather suffer having to buy another hard drive than missing a shot because I didn't shoot enough images.
Muizenberg beach huts

 

How do you shoot a bracket set on auto?
Many cameras, especially digital SLRs, can shoot a bracket set automatically. Have a look at your manual to see how to set it up for your particular camera, but don't despair if you don't have an auto setting for it either.
You will typically be able to shoot three or more images in a set, and you should be able to set your EV spacing to at least 1, or maybe 2 EV. My Nikon D7000 lets me only shoot three shots on an auto bracket set, but I can set the spacing up to 2 EV, which is why I usually choose -2, 0, +2 as my standard set. On a camera that won't go higher than a 1 EV spacing, rather shoot a -2, -1, 0, +1, +2 set.
It's very easy to do it this way, but if your camera can't do auto-bracketing, or not as big a set as you would like, move on to the next section for help. If you are hand-holding your HDR then this is by far the best way to set up your bracket set, especially if you set your camera to high-speed shooting. You can get a three shot bracket in about a second, and they will be fairly well aligned if you have a steady hand.

 

How do you shoot a bracket set on semi-auto?
I find this the easiest way if I want to shoot more than a three shot bracket set on my camera, and it should work on most cameras. Simply use the Exposure Compensation setting on your camera to dial in the settings for your set. So if you want to shoot a -4, -2, 0, +2, +4 set, then set your exposure compensation dial to -4, then -2, 0, +2 and finally +4 for each consecutive shot, and you will have a perfect bracket set. Easy as that!

 

How do you shoot a bracket set on manual?
It's not actually that scary! Here's how you would do it if your camera can't or won't do the previous two methods.
There's the briefest of theory you need to know ...
Each +1 EV is equal to one standard increment in shutter speed. Shutter speeds have had standardised speeds since the early days of photography. These speeds are (in seconds) 1 s, 1/2 s, 1/4 s, 1/8 s, 1/15 s, 1/30 s, 1/60 s, 1/125 s, 1/250 s, 1/500 s, 1/1000 s, 1/2000 s, 1/4000 s etc. You can see that each speed is half or twice the speed of its neighbour, and therefore lets in half or twice as much light into your camera. (Your camera might have inbetween shutter speeds which you can ignore for this.)
Let's say that your camera tells you that the correct exposure for the image will be 1/500 s at an aperture of f8. This is the setting for your middle shot. You know that you must only vary your shutter speed, not your aperture, so the f8 setting can stay as it is. You have decided that you want to shoot a -2, 0, +2 EV set. You know that each EV is one standard increment in shutter speed, so 2 EV is two increments.
Looking at the list above, choose the shutter speeds two increments away in each direction. Those are 1/125 and 1/2000. So to get a bracket set, you take three shots at f/8, and at shutter speeds of 1/2000, 1/500 and 1/125.
Easy! There is even iPhone software which will work this out for you, such as PhotoBuddy, but it's really very easy to do in your head.

 

TLDR and tips
  • Shoot in RAW mode. RAW files contain far more information about the scene you photographed than a JPG file would. You're already extending your dynamic range by taking a bracket set, so you might as well also extend the dynamic range of each shot by using RAW.
  • Use a tripod as much as possible. Your shutter speeds might get quite low in a bracket set, so a tripod will help keep things steady. Also, it will make it hugely easier to align all you photos later. If you're using a tripod, remember to use Mirror Up mode, switch off your lens Vibration Reduction, and use a remote to trigger the shot. Make every effort to keep things as steady and solid as possible. Your results will be much better using a tripod than hand-holding.
  • Shoot high speed if hand-holding. If you have decided not to use a tripod, shoot in high speed mode to ensure the best alignment of your images.
  • Aperture priority mode. Always set your camera in aperture priority when shooting a bracket set. If you're shooting in manual, then vary your shutter speed, not your aperture. Varying your aperture will cause your depth of field to be different in each shot, which will cause problems in the HDR process.
  • Low ISO. HDR amplifies noise in images, so shoot in as low an ISO as you can to minimize noise. Don't use Auto ISO.
  • Turn off autofocus. Your camera may decide to change focus points in the middle of a bracket set, which will ruin the set. Either keep a very careful eye on your focus, or disable autofocus once you have set the focus correctly.
  • Clean your lens. And your filters. HDR amplifies this dirt, so keep your stuff clean. You may barely notice it on your bracket set, but it will look pretty bad once you have combined several bracket images with the same specks and spots.
  • Bracket from dark to light. Set up bracketing on your camera so that it starts from the -EV settings, then 0 EV, and then the +EV settings. It will make things look a lot neater when you view them in Lightroom, and will ensure that you always keep your whole bracket set together and in order. The default of many cameras is 0EV, -EV and then +EV. That just looks messy, and it's easier to lose images that way.
  • Your standard HDR set will be -2, 0, +2. Take more shots if conditions look trickier. As you get more experience you will build up a sense of how many images to take. If you won't be back this way for a long time, take more pictures than you think you need, and delete the excess later.
  • Single Image HDR. You can dispense with bracketing entirely and make a (pseudo) HDR from one image, but you will get much better results with at least 3 images.
  • 0 doesn't have to be 0.  Your middle image doesn't have to remain at 0 EV. If you feel you camera is making a mistake you can add some exposure compensation to that image, as long as the spacing in relation to your other shots remains even. For example, you are shooting a low light scene at dusk, and your camera tries for compensate for the low light by brightening your image. You correct the camera reading by setting an exposure compensation of -⅔ EV. Your bracket set should now be -2⅔, -⅔, +1⅓. The important thing is that the spacing of shots is at 2 EV.
  • Leave out images. But only when processing your HDR later, not while shooting. Just because you have shot a huge bracket set, doesn't mean you have to use every image. If you find that the HDR process is making your dusk scene look too bright for example, you can choose to leave out one or two of the lighter images to fox the HDR software into making your image darker.
  • Watch out for people. Keep a wary eye out for things changing in your scene while you are shooting your bracket set. Look out for people walking into view, for birds or cars etc. You may need to patiently wait until the people exit your scene before you resume shooting. Some of these things can be sorted out with the ghosting tools in Photomatix, and some can be painted out in Photoshop, but you will save yourself a lot of time to just not shoot the movement in the first place. Things like trees blowing in the wind, moving clouds or waves can also make your post-processing trickier.

 

Keurbosfontein Window, Cederberg (11 exposure set)
An 11 exposure set from -5 to + 5 at 1 EV intervals. This could have been simplified to a 5 exposure set from -4 to +4 at 2 EV intervals, and still have worked just as well.

The Blue Mosque

The Blue Mosque, Istanbul  

This is the world above Istanbul.

In the old city of Sultanahmet the streets are thrumming with tourists and markets and restaurants and vendors at most times of the day or night. This lively ground level is replicated up in the sky, where every hotel jostles to have the highest roof terrace with some view of the minarets and the sea. This roofscape is the world that tourists inhabit for breakfast and dinner and sundowner drinks, and perhaps reach a vague nodding acquaintance with their counterparts on the adjacent roof terraces.

This was the view from our particular terrace one beautiful dusk in autumn last year. That's the Blue Mosque in the background, just a few minutes walk away. A benefit of staying this close to the Blue Mosque (apart from it being one of the great buildings of the world, of course) was waking every morning to the beautifully evocative call to prayer. There are apparently some 3,000 mosques in Istanbul and it's quite impressive when they all start the call just before dawn. It makes you remember that you are somewhere very exotic and far from home from the moment you wake up each morning.

HDR Tutorial: What is HDR?

Keurbosfontein Window, Cederberg  

Today I am kicking off the first of a series on tutorials on how I do HDR photography, in the hopes that I might inspire you to do the same. Earlier this year I saw an image which made me go 'wow' many, many times, and it turned out that it was made using the HDR photographic technique. I immediately downloaded some demo Photomatix software and started experimenting. I eventually spent a large part of this year learning about the technique and trying to read and practice as much as possible, and now it's time for me to pass on that knowledge. It's also just in time for a new year, and maybe for your new year's resolution to teach yourself a new aspect of photography? It's not hard, but it does need quite a bit of patience. Let's get to it!

This first tutorial is an intro to look at just what is HDR or High Dynamic Range photography? Don't worry about the acronym or the confusing sounding name. Very simply, it's a technique that allows you to photograph a scene that has complicated lighting. Where there are extremes of lighting in a scene, a camera, whether film or digital, is not able to cope with the lighting range successfully. Photography is all about capturing the light, and that light is often complicated because that's the kind that impresses us the most.

A very typical example, which is the subject of this post, is shooting an interior scene with a window onto an exterior view. It's dark inside and bright outside, and your poor camera does not have a clue how to expose this, which makes it quite sad. You can expose for the scene outside the window, but the interior will be as black as the toast I forgot in the toaster this morning. Or you can expose for the interior, but the outside will be bleached out white like you've been staring at the sun too long (instead of watching the toast).

Have a look at the before and after slider below to get an idea of the range of lighting in this scene. The darker image is shot at an exposure compensation of -3 and the lighter one is shot at +3. For those that are new to exposure compensation, 0 represents the setting where the camera thinks the scene is correctly exposed, and any + or - setting allows more or less light into the camera than the 'correct' setting.

[beforeafter]Keurbosfontein Window, Cederberg (underexposed)Keurbosfontein Window, Cederberg (overexposed)[/beforeafter]

 

Neither of these images works, but there are a couple of ways you could try and tackle this scene. You could maybe turn on the lights inside the house to illuminate the wall if they were bright enough, but this was cottage in the country with no electricity and candles were not going to cut it. You could illuminate the inside wall with a very big flash or studio lighting, but I don't own either of those, or have much of a clue how to use them. You could take two exposures, one correct for inside, and one correct for outside, and then combine then manually later in Photoshop, which would probably work quite well. But the most fun way to do it is to take a much larger range of photos to ensure that you have the correct exposure for every part of the scene, and then process them all using specialized HDR software. The software combines the images into one composite image that reflects the correct exposure for each portion of the scene. That's mostly correct, but also a little bit of a lie, because you can also have a lot of fun with the software and create the composite in a number of ways, from fairly realistic to completely lurid and over the top.

Here is the range of images I took for this scene. Using a tripod to ensure all the images lined up perfectly, I shot an 11 exposure bracket set from -5 all the way through to +5, using 1 f-stop increments. That's probably overkill, and I would usually have shot a 5 exposure set at -4, -2, 0, +2 and +4 for an interior scene like this, but I felt like going a bit overboard on this one. No real reason. I usually shoot with 2 f-stop increments, and for most images with less extreme lighting I shoot a 3 exposure set at -2, 0 and +2. Shooting a bigger set than you need isn't much of a problem other than taking more time to shoot and more space on your hard drive afterwards.

Keurbosfontein Window, Cederberg (11 exposure set)

 

These images then all get loaded into your HDR software, you get to tweak a number of sliders and settings, and out pops an HDR image. They usually look a little fuzzy and vaseline-smeared when they are freshly made, and need to be cleaned up quite a bit with post-processing in Photoshop before they are ready to show your friends.

Here's a comparison using the before and after slider of a fresh Photomatix HDR next to the fully cleaned up and post-processed HDR version of the scene. Over the next several weeks, I'll be adding several tutorials to go step by step through the whole process, from using a tripod through to Photoshop post-processing.

[beforeafter]Keurbosfontein Window, Cederberg (photomatix)Keurbosfontein Window, Cederberg[/beforeafter]

 

By the way, this picture was taken inside the cottage on the charming homestead of Keurbosfontein, close to where I photographed my previous blog image from. There was no electricity here, no cellphone reception, no people, and it was just terribly relaxing! There were beautiful gardens all around the cottage, even though we were in a very harsh and dry climatic area, and it felt like a little oasis.