How to take a 15.5 gigapixel panoramic photo
Panoramic photographs, or 360 virtual tours, have been around for many years. I can remember shooting them 10 years ago or more, yet today's versions are far in advance of those early attempts. Yet it seems that the world has moved on again.
Henry Stuart of Spherical Images recently sent me a link to an incredible picture, a GigaPan 360 of the interior of St Paul's Cathedral. (This link will take you to an external site and it may take a while to download).
Take a look, move left, right and up and down. Great, but then zoom, and zoom and zoom. The detail is just phenomenal.
I asked Henry to tell me a little more about the process.
How do you make a 360 photo?
"Virtual Tours are interactive spherical panoramas that are made up of a number of individual images stitched together and then projected in such a way as to make the viewer feel like they are actually there - it is sometimes known as Virtual Reality photography."
In this case you have used a GigaPan, could you explain exactly what it is?
"The GigaPan is a robotic camera mount that allows you to create giant panoramas that are made up of hundreds or thousands of photos. You have to calibrate the field of view of your lens and lock down the cameras settings to manual to avoid any incorrect fluctuations in brightness or sharpness in the final image. Once this is done you program in the start and end points of the panorama and let it go.
"In this case I had to auto focus each frame to ensure sharpness throughout the cathedral - this meant ensuring that the camera did not miss one shot out of the 2,500 while it tried to focus. Inevitably there were a few frames that were missed, six in total, so these had to be manually replaced in post production."
What makes this different from a standard 360 panoramic shot?
"Resolution is the primary difference. Normal 360 panoramas that you see online are around 6,000 x 3,000 pixels. [The St Paul's Cathedral shot] is over 170,000 x 85,000 pixels, or 15,500 megapixels (15.5 gigapixels)
"Essentially this means you can zoom to see detail that you could never see with the human eye from the same spot."
How many pictures did you take and how long did it take to stitch together?
"I took 2,400 images over three and a half hours at St Paul's. It took me three weeks of trial and error and posting on forums to get the image stitched, including having to seriously pimp my computer.
"The actual stitch itself took around two days of crunching, turning the computer in to a radiator."
How do you plan to develop the GigaPan 360s?
"I'm now looking for commissions to do more gigapixel panoramas - both outdoors and indoors. They can either be displayed online or printed as wallpaper and displayed on a huge scale, whole immersive rooms could be created.
"Otherwise any venue or tourism location that has ceiling paintings or mosaics would be a great candidate."
Did you need to manipulate the result at all, using HDR perhaps?
"The result is as shot, no HDR. The missing photos mentioned above were all in the floor tiles so they were cloned back in Photoshop. Otherwise editing the shot was pretty much impossible due to it's size. Any time I tried to save the image after making edits it took two hours and often the computer would crash. This meant I had to open the file again (another hour) and redo the edit. So basically it was just too time consuming and frustrating to edit the image. This is why there are so many floating heads."
Is there a way to avoid the floating heads and headless bodies?
"Shooting a gigapixel panorama can either be done in columns or rows, this one was done in rows. The reason being that if the light changed over the duration of the shoot it would be less noticeable when wrapping the image back on itself for viewing. However, it is not so good for people in shot as each row takes about 15 minutes for the camera to complete - due to the slow two-second shutter-speed needed.
"Essentially people will always be tricky when the zoom is set this high and they are so close - a person is often gone completely by the time the camera comes back round."