Understanding panorama photography and parallax

Understanding how to capture all the sight

How to capture the endless beauty, is one of the challenges of shooting expansive landscapes. Lens makers have provided us with wide-angle lenses, however they have their limitations. One of them being, it’s another lens that you have to buy or rent and carry along with you. Another, and in my opinion a more serious issue, is the difference in perspective and distortions that are introduced, far away things become minuscule and the foreground objects very large. This is definitely not a bad thing, but not always what is desired. Which is why we have panoramas, a term I’m sure many are familiar with originating from the Greek language, meaning “all sight”.

A panorama, for those who are unfamiliar, is a method where one takes multiple images and then stitch them together to form a larger image. Please do not be discouraged by the generally very mis-aligned panoramas concocted by your phones or point-and-shoots. The purpose of this article is to discuss a technique allowing the photographer to create high quality panoramas, which you will be able to make large prints with and will be pleasing to the eye. The advantage of a panorama is that you can take it using a standard lens, providing a natural point of view, whilst covering a wider angle and create high resolution images.

What do I shoot?

Before you setup your gear or take shots for the panorama, first ask yourself what do you intend to achieve?

Allow me to explain, with a panorama, you can create any of the below:

1. Wide-angle shot, higher resolution – Anything that looks like a wide angle shot. It may be a scene which you could have very well captured in a single shot but composed to pack higher resolution for a large print.

2. Ultra-wide+ – An image that capture a very wide-angle, 150 degrees, 180 degrees, essentially very, very wide.

3. 360 panorama – As wide as you can get, covering the full 360 degrees, you can print these as well as make interesting interactive tours where the viewer can rotate and zoom as he pleases. A common format for these interactive panoramas is 360º x 180º. You can also make “small planets” with these.

4. Brenizer – A technique used to create portraits with a shallow DOF and wider angle of view, something not possible with a traditional wide-angle lens.

For all of these methods one can take a single-row panorama or even multiple rows. Multiple rows require special hardware to minimise stitching errors and can get a little more complicated.

Required gear:

1. Digital Camera – Any camera will work, as long as you can lock the exposure. A DSLR is not a must, but is preferred. If you are using an SLR, any lens will work, however I’ve found myself using 24-70mm, 35mm equivalent most often.

2. Tripod – A tripod is not necessary but I HIGHLY recommend one. A tripod will reduce stitching, parallax error and assists in producing high quality panoramas. Brenizer method doesn’t really require a tripod, unless you feel more comfortable taking portraits with a tripod or if you have a very heavy lens.

3. Shutter release – Again not essential, but helpful to reduce shake, specially if you are shooting at a narrower aperture or in low-light conditions and need the longer shutter speed. You can use a 2-sec timer, but that slows things down, any shutter release will do, wired, IR or RF.

 4. Filters – I suggest you don’t use filters, specially polarisers, your skies will go crazy. Graduated filters can be problematic too, however if required, go ahead and use them, make sure to line them up correctly for each capture. UV and clear protective filters are fine.

5b. Nodal slide/Macros focus rail – This is essentially a long QR plate with a clamp at one end allowing you to mount your camera away from the tripod head. This is desired to locate the NPP (No Parallax Point) directly above the center of the rotating head. Although this item is not essential, I would suggest it if you want to create high quality panoramas, specially with close foreground objects or multi-row panoramas. Which is recommended to create a more interesting image as it gives your image a 3D feel.

5c. Spirit Level – A hotshoe spirit level is very cheap and helps to level everything out, before starting off with your panorama.

5d. Panning clamp – A panning clamp, is a clamp that has a built in QR plate at the bottom and a clamp on top which, can be rotated along the central axis. This is extremely helpful as it means you only have to level your tripod head, rather than the tripod legs as well (Explained further down).

5e. Panning tripod head – If you get really serious about panoramas and obtaining absolute precision, then you will have to invest quite a bit into dedicated panoramic heads. These are also needed if you want to make multi-row panoramas. They may have built-in multiple sliders and panning clamps to locate the NPP. These can be found in manual as well as automatic styles, manual ones require you to make the rotations and take the shots manually, automatic ones will do this for you. Examples of these are the Nodal Ninja 4 as well as the GigaPan Epic.

What is Parallax Error?

Mohit, you’ve been going on about parallax error, but what is it?

Well to understand parallax error, we must understand parallax. Parallax is the difference in apparent position of an object. This means that the object’s true position doesn’t change but seems to look like it has changed when viewed from two different positions; this becomes more evident when looking at two objects, one near and the other far away. This is less evident for two objects both far away. Parallax is responsible for our depth of perception, allowing us to see in 3D because of the two different viewing points provided by our two eyes.

Now, there is a virtual point in the lens, called the entrance pupil which is also the NPP. Without going into too much technical details, this is a point at which all light rays cross when travelling to the sensor. Parallax error is the error that arises due to rotation of the camera about a point that is not the NPP. For the camera, this is like viewing from two different points. Thus the relative position of the close objects and the far objects would be different in two seperate shots. Suppose you take your shots with 50% overlap, if there is no parallax error, the 50% of one shot would overlap perfectly with the next shot, however if there is parallax error, this would not be the case and you will see ghosting. Modern day stitching software is very intelligent and can get rid of some of the parallax errors, however as much as I love technology, I still believe in getting as much correct in camera as possible.

In the next segment of this article we’ll look into how to find the no parallax point, capture the exposures and then put them together in post process.