(N.B. This is Part 2 of my HDR Tutorial. Part 1, which is a brief introduction to HDR, can be found here.)
Right, we know now what HDR is and what type of results we can achieve from the whole process. The next step is to actually get outside and take some RAW images! For this you will need:
- A camera (essential, DSLR is highly recommended), that can shoot in RAW (preferable but not essential), and can auto bracket (preferable but will be a real pain if it can’t
).
- A tripod (preferable; I have one, rarely bring it with me on trips, and always regret not having it.)
My current camera of choice is the Nikon D300 (you can pick up its successor, the D300s at B&H Photo); it’s solid, heavy, fast, and takes great images. It also shoots in RAW, a feature found on all DSLRs. RAW is the uncompressed sensor data that is captured by your DSLR each time you take a picture. If you shoot in JPG then what you are really doing is shooting in RAW and letting your camera compress the data into a JPG before saving. This all happens in the background and requires no input from you, however you are losing valuable image information by setting your camera to shoot in JPG. HDR is still doable with a set of JPGs; it just probably won’t give you the best results.
The D300 also has that single most important feature I mentioned in Part 1: auto-bracketing (AEB). AEB is the ability of a camera to take a metered shot (that’s your initial shot), followed in quick succession by a user defined number of under and over exposed shots (remember my five thumbnail shots in Part 1?). The amount of under or over exposure is measured in exposure values (EVs). I’m sure there are entire books on just exposure. In fact, here’s one! And here’s another! However I’m going to explain it as best I can in just a few lines!
Understanding Exposure Values- A crash course.
EV is a function of your camera’s ISO, shutter speed, and aperture size, and all other things remaining constant (e.g. if you’re in manual mode), will vary like this:
- If you increase your ISO, you increase the EV. When shooting for HDR we only use a single ISO value (the lower the better to minimise noise), so we don’t need to worry about this.
- Opening your aperture, e.g. from f/11 to f/4 will increase your EV. We also only use one aperture setting, to keep the depth of field constant (I always shoot using aperture priority) so we don’t need to worry about this either. Easy so far!
- Shutter speed is where all the action happens . Increasing the shutter speed will reduce the EV. Specifically, if you double your shutter speed, say from 1/15s to 1/30s the EV will decrease by about 1. Conversely, if you half your shutter speed, say from 1/30s to 1/15s the EV will increase by about 1.
Many DSLRs, the D300 included, can be set up to automatically take under and over exposed images at EV values of ±1 and ±2, relative to the initial metered shot. In Part 1 of this tutorial my metered shot was at 1/60s, and my under and overexposed shots were at shutter speeds of 1/15s (+2EV), 1/30s (+1EV), 1/125s (-1EV) and 1/250s (-2EV). As you’ve probably realised by now this is a very, very handy feature to have on your camera if you’re interested in HDR photography; without it you would have to manually change your shutter speed to give you the proper change in EV, something I’m sure I would grow tired of very quickly! When getting any DSLR make sure it has AEB functions.
Anything else?
Yes actually! You really should get a tripod. Keeping your camera steady while it is taking multiple images at different EVs is quite tough without one; I’ve tried it handheld and it just doesn’t really work. Sitting your camera on a wall or table is a workaround but then you are severely limiting the number of directions you can point your lens . On the rare occasion I bother to bring them, I use Hahnel Triad 50 tripod legs with a Manfrotto 322RC2 Joystick Head. The joystick head is a real wonder – it allows almost 360 degree positioning for your camera with nothing more than a squeeze of the grip. A tripod is well worth investing in if your serious about tack sharp images, there are plenty to choose from over at the B&H Photo website. The Manfrotto joystick head is also in stock .
I know now what I need, what do I shoot?
I don’t know! Whatever you want! Anything can be HDRed, the trick is knowing what can be HDRed well. Personally I love landscape shots with cloudy skies, shiny vehicles are great too, oh shots when the sun is prominent can be wonderful too, but they’re a bit tricky. The best thing to do is just get out and experiment. The one thing you want to keep in mind is you’re looking for a scene that cannot be captured by a single exposure; they’ll benefit most from the HDR treatment. Some examples are a dark room with a bright window, landscapes with a glaring sun, you get the idea…
To aid this tutorial I went out, set up my tripod, fastened my D300 securely to it, set my ISO to 200, aperture priority at f/9, and AEB to take a metered shot and four others at ±2 and ±1EV. The shutter speed of the metered shot was chosen by my camera to be 1/800s. Can you work out the other shutter speeds from this? Remember I don’t have to figure out these other shutter speeds, the camera does that for me, I just tell it the EVs to use. Here are the five images I took, below it is the finished HDR.
In Part 3 we’ll actually talk about turning the five images above into the finished HDR photo. The one essential piece of software you’ll need for this is Photomatix, which can be found at Hdrsoft.com. There are others, but Photomatix is in my opinion the best I’ve tried. If you have it already that’s great, if not you can download a free trial version from the website for either WINDOWS or MAC OSX. Any images made with the trial version will be watermarked however 
.
Purchase Photomatix at 15% discount with Coupon Code “projectvisual”
If you’re feeling adventurous you can jump straight in and buy Photomatix for either WINDOWS or MAC at a discount of 15% if you use the coupon code “projectvisual”; you’ll see where to enter it if you click either of my oversized links below! Hdrsoft were kind enough to give me this code because I asked them so nicely
A quick recap.
- You’ll want a camera with AEB functions. The D300s, with a 16-85mm VR lens has them, but may be a bit expensive at over $2000! For the more budget conscience consumer, the Nikon D5000, with an 18-105mm lens and AEB controls will set you back just a shade over $1000. Of course there are cheaper ones still, browse around B&H Photo.com and see what catches your eye.
- Tripod legs and head: anything sturdy will do . Again, I’d recommend the Manfrotto Joystick Head, just because it’s unbelievably convenient.
Some final tips that I’ve learned from the D300:
- If you have slow moving subjects in your scene like clouds or leaves perhaps, use a large aperture to increase the speed at which your images are captured. This won’t help when it comes to dynamic scenes such as people moving – but there’s a way around that…
- Use continuous auto-focus; if you chose single auto-focus your camera will refocus (possibly on different subjects) between each shot, and we don’t want that now!
- Shoot in aperture priority when shooting HDR; pick your own depth of field and leave the shutter speed to the camera.
Part 3 of this tutorial will arrive early in the New Year, in the meantime I’m heading down to south Ireland to ring in the new decade
P.S. If there is some information you feel is lacking / not explained well here please lets me know and I’ll fill in the gaps
