Gunzorro
Offline
• • • • • •
Upload & Sell: On
|
(Note: Apologies in advance to all experienced advanced panoramic photographers – you probably won’t be interested in this basic summary of equipment and procedure. But anyone is perfectly free to correct my information or to expand on the various topics covered here.)
Basic Nuts and Bolts of Panoramas
I make no claim to being an expert in panoramas -- more like an avid advanced beginner.
For those contemplating the subject, I’ll list my approach and understanding.
Panos rely on software of one type or another. I won’t get into that subject, beyond what I am using currently, which is one step up from the original Canon stitch software: PS Elements 8 (v. 9 is current), with LR3 for other PP needs.
Outside of software, it is all about planning and equipment.
Care should always be taken to align the top and bottom edges while panning along the horizon to avoid distortion. A significant amount of overlap on each side is needed to ensure proper matching by the software. Many types of software can remove slight perspective distortion if the camera is intentionally raised or lowered to capture tops of buildings or foreground details – be aware that even more overlap of images is needed to cover for the sections that will be chopped off at these angles. Doing a “dry run” is recommended to establish your starting point, how many frames to shoot, amount of overlap, and to look for significant features in each frame to match with the next. My rule of thumb is to use 15-20% overlap on each side, depending on significant features that may repeat and be easily recognized by the software.
Landscape vs. Portrait – the advantage of portrait orientation is that there are far more images per pano which reduces the horizontal perspective distortion and improves resolution to the highest level. Granted, you lose a lot more image due to overlap (up to 40% total per image), it takes longer to produce one image due to more frames shot – lending itself to a tripod, and especially auto-indexing (more on this later), but the improvement in image quality is worth it.
The simplest set up is a handheld camera in landscape (horizontal) mode shooting a single row of images. In this approach you will shoot the least frames, making it easier and more spontaneous, and use your wider angle lenses to good effect.
Next in complexity is to do the same with the camera handheld in the vertical (portrait) position. In this position, you will shoot more frames and need to be more careful of your vertical camera alignment. But this method makes even your moderate wide angle and normal lenses into super-wides, due to the long side of the frame going up and down, instead of side-to–side.
The next added complexity is the earlier two methods mounted on a leveled tripod. The tripod is essential for slower shutter speeds, but is also a terrific asset at any time to keep alignment the same between frames, resulting in less loss in the software stage, which equates to wider angles of view.
Beyond a leveled camera on tripod in landscape and portrait mode comes the addition of adjustable L-brackets and base slides for placing the lens above the center of the axis of rotation (finding its “nodal point”) to reduce parallax and keep all frame breaks/overlaps invisible.
A close-up of the adjustable angled brackets for orienting camera and lens.
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9456.jpg
More sophisticated still is an auto-indexing manually rotating base plate. This plate offers adjustments to suit different angles of view in lenses, so the overlap is exactly the same from frame to frame, along the same row of exposure (single row panos are the simplest, but you can also do multi-row assemblages to produce monstrously large and detailed image files! – requires a pivoting gimbal system.
Here is a view from below of the adjustable indexing Kaidan base. The knurled brass nob on the right is the removable index stop, and the detents are the stops for various angles of view.
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9453.jpg
Finally, motorized and programmable platforms are available to automate the entire capture process.
Here's my rig for tripod mounted panos.
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9446.jpg
My set-up is fairly advanced in concept, but relatively obsolete in manufacture. My rig is by Kaidan, a US company now out of business for several years. The design of my Quick Pan II QPU-2 (circa 2000), was superseded by several version 3 units before closing the doors. This has an auto-indexing base, which is manually rotated. Some current manufacturers include Novaflex, Really Right Stuff, and Kirk. Even Bogen/Manfrotto offers a somewhat out-dated (circa 2005?) auto-indexing system. The good news about mine: despite being obsolete, despite the manufacturer being out of business, despite the lack of manual or information – the set-up works, and cost me $85+10 shipping on eBay! 
These larger pano heads need a fairly sturdy tripod if they are to be used for twilight or night shots, so I pressed my trusty Bogen/Manfrotto 3051 into service with its 3047 head with quick-release plates. In the process, I inspected and disassembled parts of the tripod, adding new lubricant to the pivot points and giving it a general tune-up (long overdue!). I even ordered a tensioning bolt to remove the play from the center column (currently has a makeshift bolt pressed into service).
At first I thought I would simply remove the 3047 head, and replace it on top of the tripod legs with the Kaidan pano head. That turned out to not be ideal. The pano base still needs to be exactly oriented, and some degree of control is needed for leveling and adjustment that can't be provided by the tripod base or the the pano base. Newer units are smaller, using ball heads and Arca-Swiss-style dovetail devices.
A significant point to be aware of is that the rotating bases (whether simply the tripod head, or the pano head) must be absolutely level, or else your horizon will be “tilty” – easily seen in any extended pano, and hilarious to see in a 360 degree pano with the horizon jumping up and sinking down. This required the greatest amount of effort in my rehab process for the 3051 legs – I had to get them perfectly level according to the built-in bubble level – guess what? – that level wasn’t level!
I had various small leveling devices around the garage from carpentry, and a camera hotshoe bubble level, so I went to work checking all the angles and making adjustments to every single bubble level in the assemblage – a total of four individual points! 1) Tripod legs (grossly adjustable by direct pressure), 2) tripod head (two directional, individually screw adjustable), 3) Kaidan base (three screw-adjustable legs), and finally camera hot shoe bubble level. All must agree, and be confirmed by exact match in 360 degree rotation. This is the hardest part of preparation.
Here are the bubble level points on my system:
3051 legs
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9447.jpg
3047 head
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9448.jpg
Kaidan rotating base
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9449.jpg
Hotshoe mount
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9450.jpg
In building a panoramic image (even if it is handheld) the rule is: everything must be perfectly level for best results. That means from the lowest variable point on up to the camera, everything needs to be exactly aligned. If that is all you learn from my adventure, I’ll be happy and satisfied.
Orienting the camera/lens – This is the next most important alignment to ensure excellent panos from a tripod. The lens axis must be directly above the rotational point of the platform it is mounted to. Additionally, there is a point in each lens that offers a perfect balance of rotation without distortion, called the nodal point, or lens node. This located in the lens, not the body or base of camera. The point varies from lens to lens. I won’t go into the method for establishing this point precisely – I made an educated guess and by eyeballing the alignment – and got very good results for images without too many prominent foreground objects.
This is where my "guess-and-by-golly" placed the camera/lens over the rotational point.
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9462.jpg
http://i25.photobucket.com/albums/c80/gunzorro/IMG_9461.jpg
Those are the basics of panoramas from my experience on the journey. You can make it as tough or as simple as you want, but best results will require greater precision, as with any activity.
Good luck on your journey and I hope this write-up helps speed you on your way.
Edited on Jun 04, 2011 at 01:43 PM · View previous versions
|
