HDR vertorama photograph inside Litchfield-Cathedral

[HDR vertorama photograph inside Litchfield Cathedral, UK by Timothy Selvage]

INTRODUCTION

This article is a brief introduction to HDR vertorama photography so that you can understand what the main components of this style of photography is. Understanding HDR vertorma photography can be easily broken into two parts, understanding what HDR is and then knowing what a vertorama is.

In following articles and tutorials I will go into further details and present step-by-step guides. Add me to your circles on G+ and follow me on Facebook where I will post links to new articles and tutorials when I publish them. So you don’t miss out, the best way to be notified is to SUBSCRIBE.

For now I’ll be addressing the following questions. If you are already familiar with HDR you can skip to part 3:

  1. What is a HDR?
  2. Why would we use HDR?
  3. What is a vertorama / vertical panorama / panorama?
  4. What equipment is needed to take a HDR vertorama photo?
  5. How do I take a HDR vertorama photo?
  6. What software is needed to produce a HDR vertorama photograph?

 

HDR

HDR stands for high dynamic range. HDR capture is used by photographers when a camera can not capture the full dynamic range of a scene in one shot. It is most easily understood through illustration. These photos were taken as a bracketed set / series.

HDR-photography

Pic 1: -2 stops underexposed
Setting: ISO 100, Aperture f8, Shutter 1/15

HDR-photography

Pic 2: ‘correctly’ exposed / ‘zero’ / ‘middle exposure’
Setting: ISO 100, Aperture f8, Shutter 1/60 

HDR-photography

Pic 3: +2 stops overexposed
Setting: ISO 100, Aperture f8, Shutter 1/240 

By using a camera where we can manually change the settings it is possible to create a bracketed series of images. The examples here show an under exposed photo, a correctly exposed photo and an over exposed photo. To keep things consistent, the separation between each photograph was 2 stops, and only the shutter speed was altered to achieve this.

Depending on your camera this can be done in many different ways and orders. People most commonly use values of -2, 0, +2. The number refers to the number of stops. A single stop either halves or doubles the amount of light reaching the sensor. To double or halve the amount of light we simply double or halve the amount of time the shutter is open. Think of it as water flowing through a tap. The longer the tap is open the more water can pass through it e.g.

1/240 sec = -2 stops (amount of light reaching the sensor is halved again)
1/120 sec = -1 stop (amount of light reaching sensor is halved)
1/60 sec = correct exposure
1/30 sec = +1 stop (amount of light reaching sensor is doubled)
1/15 sec =+2 stops (amount of light reaching the sensor is doubled again)

Pic 1
Is underexposed by -2 stops. It is considerably darker than the ‘correctly’ exposed photo. We can see that shadow information has been lost so things like the writing on the plaque can not be read. Nor can we see the door, and we have lost details in the shadows. We can not see much texture on the pillars or floor. However, this photo has done a great job of capturing the colour of the sky, the texture of the clouds, the details in the more distant brickwork, and grass.

Pic 2
Is the correct / middle exposure photograph taken according the cameras light meter when set to measure the whole scene. In this photo you can see that the camera was only able to capture a limited amount of information. Photographers will say this photo has lost the highlight details, or that the highlights are blown out. They are referring to the details and colour in the lighter parts of the photo such as the distant bricks, the grass, and most obviously the sky. When details and colour information like this is lost (is just white) photographers will say things like, “In this picture the sky is completely blown out”.

Pic 3
Is 2 stops overexposed. This photo allows us to see all the details in the shadow areas, such as the textures on the pillars, the writing on the plaque and wood grain on the door. However, the rest of the photo is severely blown out.

This is where our eyes are better than cameras as they let us see high dynamic scenes easily. Whereas the cameras ability to capture the full dynamic range of this scene was limited. The camera was not able to capture the full dynamic range of the scene.

HDR capture and processing lets us take multiple photos* (referred to as ‘brackets’) of the same scene. It can be as few as two photos or as many as 11 in extreme situations, every photo having different exposure values. These bracketed shots / brackets are then merged together. The result is an image that contains more colour information than a single image alone and can be edited to resemble how we see the scene with our eyes.

*It is also possible to make a HDR image from a single photo. This is usually referred to as a Pseudo HDR or HDR from a single image. It is achieved by duplicating the original image and then changing the exposure value to simulate brackets. 

 

Merging them together to make a HDR photograph

There are three main methods of merging bracketed images together.

1) In-camera

All you do is press the shutter and your camera captures a series of bracketed images at different exposures and then merges them together for you.

2) Manual masking and blending

This is where you take the series of bracketed photos into a program such as photoshop and mask in or out different parts of each photograph manually.

3) HDR software

There are over 20 different software packages but three of the main players are:

Photoshop – Merge to HDR by Adobe (has been available since CS3 but best from CS 5 onwards)

Photomatix Pro by HDR Soft

Merge to 32-bit HDR lightroom plugin by HDR Soft (you need Lightroom by Adobe for it to work)

HDR Efex Pro by Google

I’ll be discussing these methods in future tutorials in more detail because each method has it’s own advantages and disadvantages you need to be aware of. There is also free HDR software available. However, for the purpose of this brief introduction, the most popular method is to use software such as Photomatix that will merge the bracketed images into one HDR image.

Processing HDR photos in photomatix

You can see how easily images are exported out of Lightroom straight into Photomatix Pro. You don’t even need Lightroom and can easily import your bracketed images into Photomatix Pro directly. Here are a few examples of the software interface and results from using the presets. You can also see there are numerous sliders in the left panel that allow you to manually alter each variable to you own unique taste.

It’s important to realise that a HDR image has all the colour information packed into it from the bracketed shots. When you merge the images it is called tonemapping. You can see that there are a lot of different variables that can be altered whilst tonemapping in Photomatix. Results can range from natural looking images, to grungy and heavily textured or the crazy psychedelic. It’s up to you, but what’s important, is that you have enough colour data to retain plenty of details throughout the whole dynamic range and you are in total control of how to manage it.

Click on the images to enlarge.

Processing HDR photos in photomatix
Processing HDR photos in photomatix
Processing HDR photos in photomatix
Processing HDR photos in photomatix

So what is it?
Vertorama / Vertical Panorama / Panorama !?!!

Now that you know what a HDR photo is you can now understand what a HDR vertorama is.

A vertorama in practice is the same as a panorama but in a vertical orientation. Most people are familiar with seeing super wide panoramas of landscapes and I’m sure many of you have used real-time stitching panorama software on your phone or camera. This is where you scan a scene from left to right whilst trying to hold the camera as steady as possible and at the same level. The camera is filming / taking many pictures as you move and then stitching them together – which is why you wait a short time for the panorama to be processed.

Below you can see the bracketed photos that were taken to form each HDR photo (see explanation of HDR above). These HDR photos were then stitched together using software. To take these photos I used a tripod with a panoramic setup. The camera was rotated around the nodal point of the lens by 30 degrees increments. The amount of rotation varies according to your lens, but most it’s recommended that photos overlap between 20-30%. More is not necessarily better as it can confuse software when it comes to stitching.

Diagram illustrating breakdown of a HDR vertorama photograph

How do I take the HDR vertorama photos?

how to a HDR vertorama photograph

Equipment and camera orientation for doing HDR vertorama photography

When you’re wanting to make a vertorama you will typically start with you camera facing the floor and then take a series of shots whilst rotating the camera upwards towards the ceiling. This can be done handheld but is easier and more precise if you use a tripods and panoramic head which can be setup and corrected for parallax. Parrallax is an issue that can cause stitching errors if it isn’t corrected. I’ll be writing about it in another article but if you can’t wait, see this article by Cambridge in colour. There are different set ups each with their own advantages and disadvantages.

Here you can see an animation which shows how to put together the most basic set up that allows you to correct for parallax.

So what equipment do I need and why?

Architecture-travel-photo-St-Edmundsbury-Cathedral

HDR vertorama photography inside St. Edmundsbury Cathedral, Bury St. Edmunds, UK by Timothy Selvage

Nodal slider / arm
This is what lets you find the nodal point and correct for parallax. I decided to buy one by Really Right Stuff MPR-CL II: MPR with integral clamp as I wanted the ability to upgrade to a 360 setup.

Camera
It doesn’t matter what camera you have, however, the ability to set the ISO, aperture, and shutter speed manually will allow you to control the exposure for more consistent results making it easier to stitch the final images. It also allows you to bracket your frames for HDR. Different cameras can automate this process. I sometimes use a D7000 which can take a brackted series of -2, 0, +1 after pressing the shutter once. I also use a Nikon D800 which lets me take a series of 9 bracketed shots in 1 stop increments automatically. I can also alter the range according to the needs of the scene e.g. -4 through to +4 vs -7 through to +1.

Lens
Wide angle is brilliant for this, but needs to be rectilinear if you want straight lines. Sometimes you may want to produce a scene that looks more natural. You can’t achieve this very easily i you’re using a fish-eye lens. For many of my images I like to use the Nikkor 14-24mm f2.8

Tripod
Any tripod will do. The steadier it is the better. If you haven’t bought one yet you should read this a brilliant article by Thom Hogan. In the end I decided to buy a Gitzo

Ballhead
There are different devices to attach the camera to the tripod. Some tripods have their own built in system, whilst ‘pro’ set ups usually have a separate leg section and head. Heads can therefore be selected according to your needs e.g. video heads are different from photography heads. You just need to be able to swing the part that attaches to the camera. Normally it would put the camera in portrait orientation. I use a Markins Q10

L-bracket
So you can attach the camera to the setup whilst keeping it in landscape orientation. I bought one by Really Right Stuff – L-Plate

Panoramic rotation device – Panning clamp
Lets you rotate smoothly in equal segments. Depending on the scene, lens, camera, combination and the desired final size of the photograph you want to produce you will alter the number of degrees you rotate the camera. I’m using on by Really Right Stuff PC-PRO Panning Clamp

So what software do I need?


HDR Software
As mentioned earlier you will need software to merge the bracketed series together to form an HDR photo of each frame / camera position. In the above there were x8 images as I rotated the camera in 30 degree increments

Stitching software
In this example I used photoshop, but I also use PTGui. Each has it’s own advantages and disadvantages.

tuorial-hdr-vertorama-panorama-stitching

Selecting photoshop option for effective stitching.

stitching-HDR-photos-vertorama-pano

Selecting images in Lightroom and exporting them into photoshop for stitching is easy. Here you will see the HDR images (yellow) that I made from the bracketed series. The series of brackets I used was -5 to +1 with one stop increments. I’ll be explaining why in future articles. 

creating-a-hdr-vertorama-photograph-photoshop-tutorial

Stitched, merged and rotated vertorama ready for warping and colour editing. Next week I’ll be telling you what I look out for and why so that you can improve your vertorams. 

Photo-editing software
Once you have stitched your images together you will probably want to make some final touches to the photo. I like to use a combination of photoshop and lightroom to do this. I’ll be discussing my post-processing techniques in future tutorials so make sure you subscribe to learn more.

Conclusion

So there we have it. A complete introduction to HDR vertorama photography. We have answered:

What is a HDR?
Why would we use HDR?
What is a vertorama / vertical panorama / panorama?
What equipment is needed to take a HDR vertorama photo?
How do I take a HDR vertorama photo?
What software is needed to produce a HDR vertorama photograph?

As you can imagine there are finer details, tips and tricks as well as many pros and cons of using different methodologies, equipment and software.  Over time I will update and add more information such as step-by-step guides but I need your support and comments to do it. Help me help you.

 

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