Friday, May 14, 2010

GigaPan's (Part 1)

I have been very busy over the last few months shooting and posting 100's of new panoramic images to the Gigapan site. I have decided to feature a new Gigapan on my main site every few days and blog much more regularly. The first one up is a pano that I shot during the ANZAC Day Dawn Service at the Melbourne Shrine of Remembrance.

On the Thursday before ANZAC day I came up with the idea of shooting some panos of the Dawn Service at the Shrine. As this is a huge Melbourne event I figured it could be the sort of thing that a big pano could properly represent the scope of the crowd and the importance of the service. With 1000's of people expected to attend I also felt it could be the sort of image that could have some interest with the general public and potentially yield a physical product. With this in mind, I made a few calls around to see if I could generate some interest in the idea and thus acquire the appropriate shooting permissions to shoot the image.
I had noticed that a photographer for a local newspaper had shot some Gigapans in the past and felt maybe they would be interested in having me shoot the Dawn Service and providing them usage rights to the image. I didn't get too far with that plan of attack but did get the name of the Marketing Officer at the Shrine and she seemed keen on the idea and the next day it was all set. Now the pressure was on to capture the image and get it ready to go live as soon as possible for all to view on Gigapan.

On Thursday afternoon I headed over to the Shrine to take some test shots and review the shooting location provided to the media pass holders for the Sunday service. I was hoping to shoot from a higher location on the actual Shrine but in order to get the ball rolling with this idea I would only get to shoot from the same location as all the other photographers. I felt if I could deliver a good image from that location then maybe some better photographic opportunities would come to me with time. I headed up to the public balcony and realized a symmetrical shooting position was not available there - the best location would be the very top of the Shrine - where I expect there is only service access to change the lights. However I shot a 2 test panos in what ended up being very challenging light. One at 50mm on a Canon 7D and a second at 105mm.

I also shot a full 360 degree pano from the steps below the Shrine and at the end of this exercise I felt I at least knew the area and what I would be up against in the wee hours of the Dawn Service.

First off I knew I would need a much taller tripod for the job, a small step ladder and some help with all the gear that would need to be dragged out for 3am start to this project. Borge's Imaging provided great tripod that would enable us to get the panohead above the crowd. Sam from Borge's graciously offered to help which was a big ask considering how early we needed to start! Sam got a photo of me standing on the ladder shooting just as the crowd was at it's peak. I think I spent 75% of my time standing on that ladder shooting the crowd and Shrine over and over again. When we left at 9am we had shot almost 1800 frames. I didn't really know how many pano sets we had but it ended up being 10 in the end and many were full multi-row 360 degree sets!

I guess I should back up a bit now and point out how we shot the panos. For the last year I have been using a Manfrotto 303 SPH QTVR panohead and a Canon 5D with either a 50mm F1.4 or Sigma 15mm F2.8 Fisheye Lens. I'm very lucky that both of these lenses align with the exact same setup of the panohead. So I have the option of capturing a full 360 degree x 130 degree field of view in just 5 vertical frames with the Fisheye lens yielding a file size of ~ 11,000 pixels wide or in 18 frames with the 50mm yielding a file size of ~ 40,000 pixels wide (with of course more rows needed to gain more vertical field of view).

In February I located a used 45mm Tilt-Shift lens at a great deal and shortly thereafter I picked up a new Canon 7D and I have found these two items to be a match made in heaven. With live view on the 7D a manual focus lens like the 45mm TS-E is no longer a huge problem when it comes to focusuing it. On my 5D it was a bit more challenging to work with. I have been loving the quality of this lens both in my hands and image wise. And with the new found joy of bending the focus plane I have found it to be wonderfully creative tool to have on hand. The quality of the blur this lens gives when the focus plane is bent to reduce the depth of field is very dreamy. I have yet to add this to a pano but it is a thought and something I plan to experiment with.

I have however found that my 50mm lens seems to misbehave when in manual focus mode shooting panos on the Canon 7D. It has been yielding 75,000 pixel wide 360 degree views in 36 frames with this body but if I can't trust the focus it is not of much use. So for the Shrine project I felt I better have my focus issues locked down rock solid! With this in mind I spent the night before getting the 45mm TS-E lined up on the panohead.

I wished I could say that is an easy job but even with just one axis to adjust (of the 3 and 4th if you count the some what sloppy plate mount to the bottom of the camera!) it takes many adjustments to get the stitch seams to line up perfectly. Turns out after about 3 hours of testing my first guess was the best in the end. A more detailed description of this alignment procedure will come in a future blog post.

The end result of this somewhat wider lens on the pano head was a reduction in width to ~ 65,000 pixels and the more important (for this job at least) reduction to 24 frames (from 36) needed to cover a full 360 degrees. All in all I think a very good trade off and as long a the focus could deliver what I needed. Plus I could bend the focus plane and shoot wide open and still get some good depth of field if I wanted to give that a go.

So at about 11pm I had all the gear setup and ready to go. Just a bit of packing and loading into the car would be needed before heading out to the Shrine from Port Melbourne shortly after 3am. Just in time to get a bit of sleep....

Well that didn't happen!! Oh well no need to sleep. Just a huge shoot ahead with a never before field tested collection of gear and ideas and a wish to get a 500 Megapixel+ pano online the next afternoon!! Who needs sleep when all of that good stuff is ahead for the next day?

In the end we got the Shrine nice and early and got the best parking spot so we didn't have to carry the gear too far. No other photographers were there yet so we got the spot in our allowed shooting location. Live view on the 7D gained up enough in order to get a good focus point set with the manual focus 45mm TS-E lens. The only major problem was a huge flood light to our left (when looking out to the crowd) that was flaring up the lens. As it turned out this light was shut down in the middle of shooting my 3rd pano run. This of course killed the flare issue - but also killed what little light I was getting reflected back on the crowd from the structure of the Shrine and walls. It was looking like I would not have any light on the people without blowing out the sky until the sun started rising. It was going to be a bit of a guessing game as to when the crowd would peak, yet have the least amount of movement, and when light levels would let us balance the sky and the crowd exposures.

I shot the first frames of the day at 3:55am at 4sec, F2.8 and ISO 400. There was lots of light for this but I really wanted to shoot around F5.6 and at a lower ISO. The sky was a bit over exposed in this first test so maybe I would be able to make it work. I set up for the first row of the first full 360 degree pano and settled on 1.3 sec, F2.8 at ISO 400. At this stage I didn't know how many rows it would take to get the top of the Shrine in and all of the lower areas where the people would be standing. So I felt it would be a good baseline test run before anyone started turning up. As much as I like to bracket my pano frames when ever possible I didn't think it would work out for this first run at these longer exposure times. Anything on the 5D/7D over 1 sec needs the "dark frame subtraction" noise reduction or else there are hot pixels all over the frames. So that doubles the exposure times basically. And with the over exposed frames needing 2.5 to 5 sec each (if 1 or 2 stops over) it would take at least 15 to 20 seconds for each frame location and with 24 needed to sweep the full 360 degree it would take too long to get a multi-row pano shot.

In the end the first run was a 4 row pano that took 38 minutes to shoot. The total field of view was looking good but the shooting time certainly was going to be an issue once both people and light started changing rapidly. A proof version is below. I have yet to go any further with these frames as the next full 360 run looked much better.

The 2nd run ended up being a 3 row version shot at 6 sec, F2.8 and ISO 100. Somehow a frame was missed on the top row but it ended up being a relatively easy fix to substitute a replacement frame in from the 1st run. A conversion of the RAW files was done cooling down the overall white balance of the frames. This really brought out the deep blue sky that we had not really noticed yet as we were still shooting in camera jpg's with a much warmer setting. Shooting time for this run was about 25 minutes. A proof is below and click here to view a 114 Megapixel version of it.

Run 2 finished up at 5:07 am and within a few minutes the flood lights turned off and the Shrine went into total darkness. Sure the lens flare was a problem - but the Shrine was looking good and as run 2 turned out - the look ended up being pretty dramatic. Now without the flood lights the crowd was in almost total darkness and a 15sec exposure at F2.8 and ISO 100 was not showing much of them. Things all of the sudden were not looking good. The emergency plan may require blending rows with different exposures and that is never easy!

(more to come in Part 2......)

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