Free HDR Tutorial Step 1 – Capturing the Image
How to set up your camera
I have found I get the best results if I use several exposures for my HDR images. You can use just one RAW image and there are times when that is what you will need to do to create your HDR photo. In most cases though, you will be in a position where you’re able to take multiple exposures. We will have a look at when a single RAW photo is best shortly…
Okay, we have spoken about ‘multiple exposures’ and ‘auto-bracketing’ and for some of you this may sound like another language. HDR stands for ‘High Dynamic Range’, for you to capture the dynamic range of a scene, you will need to take several shots of the same thing, and as you take each shot you will change the settings slightly each time. Typically for HDR you will want a minimum of 3 exposures, one that is correctly exposed, another at -2ev (under exposed) and the third exposure over exposed at +2ev (EV stands for Exposure Value). Click on the image below to make it bigger, you will see that there is some detail lost in each shot, but if we were to blend them all together and kept the best bits, we will end up saving most of the detail.
Thankfully, a lot of cameras have a function called ‘Auto-Bracketing’ that will capture the multiple exposures you need, automatically. In the case of my Nikon D800, it will automatically bracket my exposures, but only at a 1ev spacing, so to get the 3 exposures I need, I actually have to take 5 shots (-2ev, -1ev, 0ev,+1ev, +2ev). When I am shooting into the sun as in the example above I will want more, usually I will bracket from -3ev to +3ev, sometimes more (remember, it is free to shoot as many frames as you want), to me, it is like an insurance. I often will take more than I need and sometimes I won’t use all of the exposures when I create my HDR.
For the image we’re working on today, I wanted to go from -3ev to +3ev, and with my Nikon D700 I was using at the time, I had to take 7 exposures to get what I needed. Click on the image below to see more detail. You will see that each exposure has managed to capture different details from the scene. None of these exposures on their own look like what I saw the morning I was standing there, but by merging these together I can create what my eye’s and brain created that day.
I almost always use Aperture Priority, on your Nikon this is the mode denoted with an ‘A’, a lot of cameras will just use an ‘A’ for Aperture mode. Some though, like Canon, have their own quirky ways, they call this ‘AV’ mode, this stands for Aperture Value. Anyway… just get out your manual and work out how to shoot with Aperture as the Priority. I usually shoot at an aperture of somewhere between f8 and f13 unless I have a reason to go outside of this, for example very bright condition and I want some water blur or at night time I will shoot at f5.6 or something like that to allow for the lower light. The Shot we’re working on today, was shot in Aperture Priority at F9.
Usually I will set the base ISO available for the camera. My D700 was ISO200, my D800 is ISO100 and my Fuji X-E1 is ISO200. Once again, unless I am trying to capture something specific that requires me to increase the ISO I leave it as low as it can go. As soon as you increase ISO you will increase noise (grain) in your images, and HDR processing just makes it worse again.
I set my camera to ‘Matrix Metering’ (that’s Nikons name for it), Canon calls it ‘Evaluative Metering’ – In this mode your camera will average all of the light information and expose for what it thinks will be best overall. Using this mode will give you nice consistent exposures every time you shoot.
I shoot RAW… I love saying that… I don’t know why… it just sounds cool! Anyway, I am a boffin when it comes to remembering to reset things like white balance so I just shoot RAW. This means that I can adjust things like white balance later and the other upside is I can also manipulate the light information in a single exposure if I feel the need.
On that note, a single RAW file can be used to create your HDR image. You would want to do this in certain circumstances. For example, If something was moving as you took your 3 exposures, it then becomes a big blur or ghostly when you make your HDR in Photomatix… so instead, take the correctly exposed RAW file and using your software of choice, you can make a +2ev and a -2ev out of the one RAW file exposure, that way all 3 exposures will be exactly the same! There are other ways to deal with the blur and ghosting created by things moving in your shot too, I will cover that in step 3.
I like to use a tripod. You don’t have to, as Photomatix has an ‘Align Source images’ function that does a pretty good job… however, it won’t fix blur and quite often I will shoot at times when my shutter speed for the over exposures will be too slow for hand holding, so a tripod is a must. Get a tripod and use it… your images will be sharper anyway.
Once your camera is on the tripod, the best way to ensure sharp images is to give yourself as few reasons as you can for touching your camera, and this gives you a reason to buy another gadget! I use a wireless remote, I bought it on eBay for about $20. You may already have a wired remote, they’re fine… or the other alternative is to use the timer, so after you press the shutter button your camera has a few seconds to stabilise (sounds fancy!) – I get my auto-bracketing to start with the underexposed image first, this way the camera is doing it’s fastest shutter speeds nearest the time I had to touch it (if I didn’t use my remote)