Sunday, 22 June 2014

Panorama Photography

What is Panoramic Photography Tutorial
by Kathy Roman

1) What is Panoramic Photography?
Panoramic photography, also known as wide format photography, is a special technique that stitches multiple images from the same camera together to form a single, wide photograph (vertical or horizontal). The term “panorama” literally means “all sight” in Greek and it first originated from painters that wanted to capture a wide view of a landscape, not just a certain part of it. The first panoramic photographs were made by simply aligning printed versions of film, which did not turn out very well, because it was close to impossible to perfectly align photographs. With the invention of personal computing, advancements in computer software and digital photography, it is now much easier to stitch digital images together using specialized software. In fact, using a proper photography technique and panoramic equipment, it is now possible to create near-perfect panoramas at extremely high resolutions. Some photographers even stitch hundreds of high resolution images to create gargantuan “gigapixel” panoramas. Today, digital panoramic photography is quite popular and common not only among landscape photographers, but also among architectural and cityscape photographers.

Panoramic Photography can get quite complex and expensive, depending on what you are trying to do. For example, creating panoramic images in architectural photography requires camera and lens to be properly calibrated on special panoramic equipment to prevent curved lines, distortions and improper stitches of close objects. At the same time, you can successfully take great landscape panoramic images without investing on any camera equipment, as long as you know how to do it right.  this article,  will primarily focus on taking panoramic images either hand-held or with a tripod, without spending on any other equipment.

2) Types of Panoramas
While the word “panorama” automatically assumes that it will be a wide horizontal or vertical image it does not necessarily have to be. If you stitch several images together and it turns out to be a square image, it is still consider it to be a high resolution panoramic image.
    Wide angle panoramas – anything that looks like a wide angle photograph, which covers less than 180 degrees, whether horizontal or vertical. Wide angle panoramas can even look like regular images, except they are stitched from several photographs and therefore would have more resolution.

2) 180 degree panoramas – panoramas that cover 180 degrees from left to right. These types of panoramas look very wide, covering a large area.

3) 360 degree panoramas – panoramas that cover up to 360 degrees. These panoramas look extremely wide and they cover the whole scene in a single, super wide image.

4) Spherical panoramas – also known as “planets”. These are 360 degree panoramas that are converted to a square spherical image using a special post-processing technique.

Spherical Panorama
All of the above panoramas can either be photographed in a single row (meaning one row of vertical or horizontal images) or multiple rows (higher focal length is often used to yield much higher resolutions. Multi-row panoramas often require special panoramic equipment).

3) How to Photograph Panoramas
Let’s now get to the meat – how do you capture panoramic images that will be used to create a panorama? There are two ways to capture panoramic images:
  1. Taking Landscape shots – an easy method for quick panoramas, where resolution is not important.

  1. Taking Portrait shots – a preferred way to capture panoramas. Vertical images capture more of the sky and ground and yield higher resolution panoramas compared to horizontal ones.
  2. Depending upon the subject matter it is often better to avoid shooting horizontally, as you lose too much resolution due to some cropping that is required after the panorama is stitched by software. Vertical panoramas are much better in that regard and they always yield more resolution than horizontal panoramas.
The shots I took overlap each other by approximately 30-50%. In order for any program to be able stitch multiple images together, the images have to overlap each other by a certain margin, so that alignment points are properly identified. The alignment points serve as flags for the stitching algorithm that seamlessly merges the images and cuts out the rest of the image. The overlap margin is a subject of opinion and while some people recommend 20-30% overlap, I personally do it by about 50% (see why below).

3.1) Camera Equipment
  1. Digital Camera – as far as the camera itself, any camera should work, as long as the exposure (aperture, shutter speed and ISO) can be locked. Ideally, you want a digital camera that can shoot in full Manual mode (preferably a DSLR).
  2. Lens – The find zoom lenses to be the most useful for panoramic photography. You can certainly photograph panoramas with fixed/prime lenses, but being able to zoom in and out will give you more options and versatility, especially in difficult conditions where your movements are limited. If you have a DSLR, any wide zoom lens such as Nikon 18-55mm or Nikon 18-200mm should work perfectly fine. I personally use the Nikon 24-70mm f/2.8G lens for most of my panoramas and I have been very happy with the results.
  3. Lens Filters – Its recommended taking filters off your lens while shooting panoramas. It is OK to keep a clear filter on, as long as it is not introducing any vignetting to your images on the wide end. Definitely remove a circular polarizer if you have one mounted on your lens, because it will colour your sky in varying shades.
Tripod – a tripod is optional, but highly recommended for best results. Any sturdy tripod should work, but make sure that the head is flexible enough for you to be able to pan from left to right with ease.

No tripod:1. Attach a string (with a weight on one end) to the end of your lens.
2. Hold your camera up, and observe where the string touches the ground. You will take all photos with the string touching this exact part of the ground.
You also have to be very careful to keep the camera on the same plane so that when the photos are stitched together you don’t have the black gaps as you see here.
  1. Cable Release – optional, but recommended for capturing shake-free images.
  2. Panoramic Setup – a full panoramic setup is ideal for best results, but it is very expensive ($500+). Not recommended for beginners due to complexity of use, but a must-have for professionals that want to sell their images.
3.2) Camera Settings
Before you start taking panoramic images, you have to change some of the settings on your camera. Here is what I recommend to set in your camera:
  • Shoot in “Manual” mode – the most important thing in panoramas is consistency of exposures. It is imperative that no matter how bright or dark parts of the scene might be, your images must have the same exposure. If your camera allows locking exposure, you can certainly shoot in other modes, but I suggest to shoot in Manual mode to prevent possible accidents.
  • Set your lens to Manual Focus – if you have a DSLR, focus your lens on a distant object (infinity or near infinity), then switch to manual focus. You do not want your camera to change focus every time you take a picture.
  • ISO – make sure that “Auto ISO” is turned off and set your ISO to the camera base ISO (either 100 or 200).
  • Aperture and Shutter Speed – for panoramic images, you want to have everything in focus. Therefore, make sure that your aperture is set to a good number that will put everything, including any foreground elements, into perfect focus. Depending on your lens focal length, you should set your aperture to at least f/8, preferably f/10 and higher (depending on how close the nearest foreground object is). Once you set the right aperture, set your shutter speed based on the meter reading as explained below.
  • Metering – in terms of metering, do not meter off the brightest or darkest areas of the scene, but rather try to find a “sweet middle” and set your shutter speed based on that area for the entire panorama. Take a couple of pictures and make sure that the images are not too overexposed or underexposed for the brightest and darkest parts of the scene.
  • Lens Focal Length – ultra wide and wide-angle lenses below 24-28mm on FX sensors and 16-18mm on DX sensors typically have heavy distortion and vignetting issues that can make it difficult to properly align and stitch images. Typically, the focal lengths that work best for panoramas are between 28mm to 50mm on full-frame FX bodies and 18mm to 35mm on DX, depending on the lens.
  • Shoot in RAW – I always recommend shooting in RAW for best results.
  • White Balance – set your White Balance to “Auto” when shooting in RAW and change later, if necessary.
3.3) Shooting Technique
  1. Identify the area you want to photograph. The first thing you need to do, is identify what you want to capture. The best candidates for panoramic images are overlooks, i.e. standing on the top of a mountain or hill, or looking down from an elevated area with no near objects. Avoid shooting panoramas with trees, bushes and other objects in the foreground, unless you have special calibrated panoramic equipment. If you are shooting a scene that is far away from you, the panorama will stitch perfectly, because the software will not have to deal with parallax errors.

Watch for wind and other moving objects. Wind can move tree leaves, grass, water and sand in different directions, which will spoil your panorama. Only shoot in windy conditions when the wind strongly moves everything in one direction. Avoid taking pictures of moving water waves. Pick the right scene

Motion can be a real problem in a panoramic image, because the software you use to stitch the two images together may not know what to do with overlapping parts that don’t look exactly the same. So that big beautiful pine tree in the foreground with branches waving in the wind might actually ruin your shot, or at the very least force you to stitch those images together manually. Cars, people and other moving objects will also be a problem. If you can, it’s a good idea to time your images so that these little intruders don’t become a problem in post-processing.
  1. If you will be using a tripod, set the tripod on a firm surface and level it. Once it is leveled, mount your camera on the tripod horizontally or vertically and firmly tighten it. Make sure that you can freely pan the camera from one side to another without letting it change any angles. Try to watch for alignment errors by matching the lines in your viewfinder with the horizon.
  2. If shooting hand-held, keep the camera close to your eye and look through the viewfinder instead of the back LCD. Pan from left to right and see whether you can keep the camera straight and aligned against the horizon.
  3. Set your camera settings as shown above and make sure that the exposure is fully locked.
  4. Check camera focus and make sure that autofocus is disabled.
  5. Note the starting point and ending point you will be photographing and visually remember both.
  6. Take a single picture and see if the image looks good on the back LCD. If the image looks good, you are ready to shoot. If it doesn’t, check your exposure settings and make changes, if necessary.
  7. Point your camera at your starting point on the left and take the first picture. Before you move the camera, remember where your center focus point inside your viewfinder is pointing, then start moving the camera to the right, until that point is at the center edge of the frame. This basically means that you will be overlapping your new image with the first one by approximately 50%. Take a picture and repeat this process until you get to the end point. Remembering where the center focus point is at relative to the scene is the easiest and safest way for me to make sure that the images overlap enough for post-processing software to be able to stitch them later. You can certainly overlap them by a smaller margin and decrease the total number of images, so it is totally up to you on how you want to do this. Just make sure that the images overlap by at least 20% and there are visible stationary objects that will allow the stitching program to identify them and connect them later.
  8. If shooting hand-held, stand in one spot, keep your elbows close to your body and rotate only the upper part of your body, keeping the camera close to your head at all times. Imagine that your legs are a tripod and your upper body is a tripod head. This will minimize the effect of parallax on your images.
  9. Once you are done taking the pictures, visually inspect all images on the LCD at least once to make sure that you do not have any problems with your setup.
The easiest and quickest panoramas can be done by hand-holding your camera.

 3.4) Using a Panoramic Head
If you want to get serious with panoramas, you should invest in a good panoramic setup, which will allow you to take pictures without worrying about parallax issues. There are plenty of different solutions out there and the most popular ones are by Nodal Ninja, Manfrotto and RRS, the latter being the number one choice for professionals. With a good panoramic head, you can have the camera setup rotate around the entrance pupil of the lens and take perfect single-row or multi-row panoramas that will stitch without any problems.
The biggest challenge with panoramic photography is stitching problems due to parallax errors. (Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.[1][2] The term is derived from the Greek παράλλαξις (parallaxis), meaning "alteration". Nearby objects have a larger parallax than more distant objects when observed from different positions, so parallax can be used to determine distances.)
4) Stitching Panoramas in Software
Once you are done taking the pictures, you then need to stitch them using specialized software that is capable of handling panoramas. I’ll talk about how to use Photoshop, PSE and Microsoft’s Image Composite Editor (“ICE”). There is also PTGui and many more on the web.
4.1) Using Adobe Photoshop
Stitching panoramas in Photoshop is super easy. If you use Lightroom, simply select the images and then right click, “Edit In”->”Merge to Panorama in Photoshop…”. If you do not use Lightroom, simply open up Photoshop and then go to “File”->”Automate”->Photomerge…”. A dialog box will come up that looks like this:
The images will automatically show up if you use Lightroom. If you do it from Photoshop, simply click “Browse” and select the images to be merged into a panorama. Make sure that “Blend Images Together” and “Geometric Distortion Correction” are checked, then click OK. This will start the stitching process, which can sometimes take a long time, depending on the number of images and their size. Once the process is completed, all you have to do is crop the image and you are all set!

Post processing: how to complete your image

You can stitch your panorama together manually, which with practice may actually give you better results. But in this tutorial we’re going to talk about the faster way, which is to use Photomerge in Photoshop Elements. Here’s how:
In “full edit” mode, choose File > New > Photomerge Panorama. You’ll get a pop-up menu asking you if you want to use individual images (“Files”) or all the images in a single folder (“Folders”). Alternately, you can just open all the files you want to use prior to selecting “Photomerge Panorama,” then you can choose “add open files.”
If you choose “Files” or “Folders,” you’ll then need to navigate to the directory where your photos are stored.
Now choose “perspective” from the layout menu. (You can also choose a “cylindrical,” “spherical,” “collage,” “reposition” or “auto,” but for the type of panorama we’re discussing here you will want to stick with “perspective.”) In the perspective layout, the software will choose the center image as its reference point, and then stitch all the other images together around it, skewing, stretching or repositioning as necessary. Note: there is also an “interactive” layout, which allows you to manually position everything.
Now Photoshop Elements will give you the option of blending the images, which means it will select the best place to join the photos and will blend the colors in order to create an invisible seam. You can also choose to remove any vignettes that may have occurred in the images when you were taking them, and to correct for distortion. It is, of course, better to avoid these problems rather than expect Photoshop Elements to fix them for you, since the software may not do a perfect job after the fact.
Now click “OK.” The software will ask if you want to fill in the transparent edges; if you say “yes” it will add “content-aware” healing to the edges.
And that’s how it’s done – at the basic level, of course. You may find that you aren’t completely satisfied with the job Photomerge does; that’s when it’s time to re-evaluate your technique and perhaps learn how to use Photomerge in interactive mode. Or just do it all manually. Whatever you decide, panoramic photos can be a great way to present a truly compelling image of a landscape or other fantastic piece of scenery. After all, it’s really hard to reproduce the splendor of a landscape in two dimensions. But when you do it in 180 degrees, you’re going to come a lot closer to giving your viewer the impression that he’s standing right there with you, taking in the view.
4.2) Using PTGui
PTGui has a lot more stitching options than Photoshop and you can customize pretty much anything, even manually set control points and select various stitching algorithms.
How To Take Great Panorama Photos With The iPhone
Posted by: Emil Pakarklis
Show how to take panoramas on Iphone: touch photo icon: touch options: touch panorama. Keep line in centre
In general, the iPhone’s built-in panorama does a great job at stitching together multiple images. As you can see above, all transitions are done flawlessly, thus making the built-in panorama feature a good choice in most situations.
However, the iPhone’s built-in panorama has two disadvantages. First, it tends to struggle with exposure in scenes that have a high dynamic range.
The other disadvantage is that the height of your image is limited by how much you can see through the lens of your iPhone in portrait orientation. Other panorama apps allow you to create higher panorama photos, but this feature is not available in the iPhone’s built-in panorama mode.
Option 2: 360 Panorama App
Another way to crate panorama photos with your iPhone is using the 360 Panorama app. This is a paid app, and it’s currently selling for $.99 on the App Store.
In general, I was rather disappointed by how 360 Panorama performed. The sky is severely overexposed and the coastline in the center of the photo is not stitched accurately.
On the other hand, the “virtual reality” panorama viewer that I mentioned in the video is really cool. If you want to play around with it and have some fun, you should buy this app. Otherwise it’s probably not worth it since the stitching algorithm is quite inaccurate.
Option 3: Photosynth App
Another way to capture panorama photos is using the Photosynth app by Microsoft. This app is currently free and it also offers advanced panorama functionality. This photo has been stitched very accurately, and the exposition is accurate throughout the image. The iPhone’s built-in panorama mode did an equally good job at stitching, but Photosynth appears to be better at maintaining proper exposure throughout the scene.
In general, the stitching is done accurately, but there are significant issues with color and brightness in the central part of the image.
It appears that the app had a hard time dealing with the extreme dynamic range in the central parts of this photo. The results would probably be better in a scene that has more even light.
From the panorama apps that were tested in this article, Photosynth seemed to perform best. It’s stitching was very accurate, and it was able to maintain a proper exposure throughout the scene better than the other alternatives. And best of all, it’s free. You will get the best results with Photosynth if you only stitch images horizontally, and not vertically.
The iPhone’s built-in camera app is also a good option, but it seems to perform worse than Photosynth when the exposure has to be very different throughout the scene.
Extra Tips
You should avoid moving subjects when taking panorama photos. Since panorama photos are stitched together from multiple separate images, you are going to have problems if the scene is changing while you’re taking a panorama. Similarly, you should not move much since your own movements will change the angle from which the photos are taken.
These principles are nicely explained in the help section of Photosynth.
With that said, it’s practically impossible to keep your iPhone in the exact same position while you keep moving around to capture a panorama. However, you can minimize the impact of inadvertently changing the position of your iPhone by only capturing distant views. The further your subjects are from you, the less worried you have to be about moving your iPhone too much.
Finally, panorama images allow you to get creative in ways that wouldn’t be possible otherwise. Have you ever wanted to have the same person casually appear in your photo twice? With panorama photos you can do exactly that…