Panorama comes from two words that literally mean “all” and “sight”. The purpose of a panorama is to captures as much of a field of view as possible, usually by combining several individual shots into a single image. High Dynamic Range (HDR) panoramas combine High Dynamic Range photography with panoramic photography techniques.
Panoramic images date back to before photography, as there are many panoramic paintings. Panoramic photography is as old as photography itself. The first photographic panoramas were simply shots overlaid on top of one another. More sophisticated techniques were invented to create what appeared to be “seamless” photos. With modern digital photography, this is easy to accomplish with panoramic stitching software, which we will cover later. With this in mind, this tutorial will show, how to compose an HDR panorama, then generally cover the post-processing of such images.
First, what you will need:
- Tripod – preferably with a panhead. This is the sort of head that has independent handles for the pitch, yaw, and roll of the camera. “Ball” heads usually have some sort of ball-in-socket mechanism for moving the camera around. These aren’t really conducive to panoramas, unless the head also allows for panning too.
- Camera — Most any camera will work so long as it allows you to manually control the shutter speed.
- HDR software (Luminance HDR, Photomatix, or PhotoShop)
- Stitching Software (Hugin, Photoshop)
- Lens Hood
Taking the shots
- Determine the limits of what you want to photograph. This is important. Without this limit, you will either get too much or too little when photographing the subject. You can do this by choosing a landmark in the field of view.
- Mount the camera in portrait mode for horizontal panoramas or in landscape mode for vertical panoramas.
- Choose an aperture and leave it there! You’ll want to use the same aperture for the entire composition. For general purpose panoramas, I think f/9 – f/11 works fairly well. You may want smaller apertures if you need long exposures or something like that.
- Set the camera on manual mode. With some cameras, you may be able to use aperture priority rather than manual mode because of AEB – Automatic Exposure Bracketing or similar programming. In any case, you want to leave the aperture consistent through all the shots used to compose the panorama to avoid variable depths of field.
- Take some samples from bright spots and dark spots in the field you want to capture. Note the shutter speeds of the various shots. If you’re camera does not have AEB, you’ll want to figure out the range of shutter speed you will need to capture the dark and light areas of the shot so they are not burned out or blacked out in the final image. That is, it may require a long exposure (say ¼ of a second) for the darks and a quick exposure (say 1/200 of a second) to get the details in the bright areas.
- Determine the number of shots you will need to take. This is a function of the width (or height) of the panorama and contrast of between the light and the darks.
- Conventional panoramas are usually composed of “slices”. I found overlapping images by 50% give pretty decent results for panoramas, as usually, the outer extremes are cropped out and I only use the center portion to the image appears more natural. This means that if 6 slices covers the area I want to capture, I will take 8 slices knowing I’m likely to crop out the half of the two edges, but need this information so the panorama software can correct the distortion.
- Next, determine the number of images needed to cover the contrast (that is dynamic) range. (This is kinda technical…hold your breath) In the example earlier, I needed 1/4 of a second to 1/200 of a second to properly expose the content of the panorama. This is a rather large dynamic range. In theory, for any shot at a given shutter speed, doubling the shutter speed would mean that the sensor only receives half the light, which would correspond to one full stop on a camera. A digital camera shooting in RAW has a range of around 8-9 stops while JPEG is about 5, which means that a properly exposed image would have about +/- 4 stops each way for RAW and +/- 2 for JPEG. This means I need to set the camera at ¼ of a second, 1/32 of a second, and something around 1/256 of a second (1/250 would probably suffice) to capture the full dynamic range of the image. These are 3 stop intervals, but the camera could do it with 4 stop intervals. It is also good to have overlap here too, and with HDR, the more the merrier, I could do it in 2 stop intervals to get even better results. This would be necessary however for JPEG.
- This means 3 shots per slice for 8 slices, a total of 24 exposures. Each color in this sample represents a relative slice, each overlapping the previous slice 50%.
- Start the pan by centering the camera on what you determined to be the edge of the field you want to capture and start taking shots at the lower shutter speed. Move up to the next interval, then take the shot. Repeat this for each determined shuttered speed. Then move the center so the edge of the frame is where the center was. This means 50% of the previous 3 shots will be in the next set, and repeat the process for the determined shutter speeds. You’ll want to avoid camera shake and want to lock the pan head with each exposure to make sure the camera does not move between each slice and HDR. Click the shots, then move to the next slice. You’ll want to do this as quickly as possible, (but not to get in a hurry!) because sometimes items in the panorama can change such as clouds or shadows. I cropped out the extremities on this shot, I was principally going for what is shown, so for this reason shot a lot of extra so I’d have lots to play with.
HDR Panoramas are time intense on taking and in post processing. The example used in this tutorial took nearly an hour! The basic strategy here is to first, create HDR for each HDR slice, second create a panorama for these HDR slices, then 3 perform HDR post processing on the HDR Panorama.
- To combine each HDR slice, open your HDR software and work through the wizard for each slice. This typically means selecting each image that composes the slice and letting the software align merge the images into an HDR. If you are using the same software that combines images to HDR that you will need to merge the images, you may not need to save the images, although this is recommended because HDR and Panoramas by themselves use tons of RAM, so you may want to have only one slice loaded in memory at a time to conserve system resources. Luminance HDR (a.k.a. qtpfsgui, a free HDR Workflow) and Photomatix are two independent programs that perform HDR. Photoshop since CS2 performs HDRs and will do panoramas too. Here’s a tutorial on composing HDR’s in Photoshop. Luminance HDR (aka qtpfsgui) does pretty well to. Check out post processing in my HDR Waterfall tutorial for a how to on this. If you use a separate software, you’ll want to save the images out in some format that supports 16 bits per channel (or more), such as TIFF files. JPEGS, PNGs, and BMP use 8 bit. Saving in these formats will hinder any post processing after the panorama is created. WHATEVER YOU DO, DO NOT TONE-MAP THE IMAGE! This will be done after the panorama has been created. Save each HDR slice in a separate file for combining later in the panorama stitching software. Here are some samples for one of my slices I used in making the HDR Panorama in this guide:
- Next, open your panorama software and created the panorama from the HDR’s you created from each slice. Photoshop’s “Photomerge” wizard (File –> Automate –> Photomerge) does a phenomenal job at combining images and creating panoramas. There are some free tools such as Hugin will create panoramas quite nicely too, albeit it is more technical to use. These programs will walk you through a wizard like interface and combine the images. Photoshop does not “flatten” the image (that is combine the layers it creates into a single image) when you are done with it, so you’ll have to do this manually. You’ll want to crop the image too afterwards. Hugin and others will do this for you, so use the software accordingly. As before, you’ll want to save the image in a 16 bits-per-channel or 32 bits-per-channel when finished.
- After creating the panorama, take the panoramic image back into your HDR software and perform tone mapping on the image as you would any traditional HDR photo. The tone mapping will attempt to compress the high contrast image into a dynamic range suitable for onscreen viewing such as a JPEG. Once you have tone-mapped the image you may want to perform some other adjustments such as levels, saturation, and balances, but this is purely discretionary.
Here are some examples I did using these techniques.
I hope you have found this tutorial helpful. Happy shooting!