Posted by John Freeman on December 13, 2014 at 11:17 PM
Here is a little project that I tried just for fun. I was up at RMNP this past Thur. and in late morning I was bored waiting for afternoon light. I was parked at the Beaver Meadows Overlook and decided to try doing a panorama using my 800mm Sigma telephoto lens. The view up the valley toward Notch Top Mountain was spectacular. I did a 17 column x 3 row series of shots. I stitched them together with Autopano Giga. The colors were kind of off due to the distance. I was about to delete the files when I decided to convert to B&W to see what it looked like. This is what I got.
Final image is 80' x 40" (24,000 x 12000 pixels)
This is a link to high res viewer
http://www.abbascreationsphotography.com/Notch%20Top%20Panotour/Notch%20Top.html
Very interested in you all's comments.
Posted by Monika Chace on December 14, 2014 at 9:23 AM
John, nice effort there. I'd like to see stronger blacks or maybe it's just stronger detail on Notchtop (it looks OK in the small, compressed one, but on your high res viewer on my big monitor, it looks a little on the flat side) . The soft focus trees in the foreground are a little distracting. It's probably just me, but it took a while to figure out to hold down a direction key to stop the image from scrolling right and left, which made viewing it difficult. Or maybe I've just spent too much time driving recently?
Posted by Bill Pelzmann on December 14, 2014 at 11:28 AM
That's an instructive exercise while waiting. With such a large, high resolution image, I would expect it to be sharp throughout. I assume the lower third is not in sharp focus because of the very shallow DOF at 800mm. If you try a similar multi-row pano again, I'd suggest changing the focus for the lower row.
I understand why the foreground trees are soft, however, on the high res viewer, the basin below and right of Notch Top is also softer than Notch Top. Since this is at essentially the same distance as Notch Top, I don't understand why.
As Monica, I'd prefer higher contrast, but that's a matter of taste.
Thanks for sharing your experiment.
Posted by John Freeman on December 14, 2014 at 12:04 PM
Thanks Monika and Bill for your comments. Yes, DOF is a issue with 800mm. I ran into a couple difficulties while attempting to shoot this. There was some wind and even with my fairly sturdy tripod I was getting some shake. I went to ISO 1000 to get the fastest shutter speed possible. This series was shot at 1/4000th of a sec. and f-5.6. Even with the fast shutter, having done lots of stitched images I can pick out a couple frames where I detect blurring due the shake of the lens. Bill one of those frames is in basin below and right of Notch Top that you noted.
Lesson 1 learned from this experiment is don't attempt this kind of shot on a breezy day. You need dead calm.
Lesson 2, close down the f stop as much as possible to maintain DOF.
The thing that I expected someone to pickup on was the variation of luminance from left to right in the sky. Due to significant vignette that the lens exhibits I had a lot of vertical bars of luminance variation that I spent considerable time air brushing an exposure mask to compensate for. I first thought this was due to the polarizer. However, after reviewing most of the skyline images, I am fairly convinced it is more the len's vignette. You can see the vignette very clearly in the single frame from the series I have attached to this post.
Discussion
3 repliesFinal image is 80' x 40" (24,000 x 12000 pixels)
This is a link to high res viewer
http://www.abbascreationsphotography.com/Notch%20Top%20Panotour/Notch%20Top.html
Very interested in you all's comments.
I understand why the foreground trees are soft, however, on the high res viewer, the basin below and right of Notch Top is also softer than Notch Top. Since this is at essentially the same distance as Notch Top, I don't understand why.
As Monica, I'd prefer higher contrast, but that's a matter of taste.
Thanks for sharing your experiment.
Lesson 1 learned from this experiment is don't attempt this kind of shot on a breezy day. You need dead calm.
Lesson 2, close down the f stop as much as possible to maintain DOF.
The thing that I expected someone to pickup on was the variation of luminance from left to right in the sky. Due to significant vignette that the lens exhibits I had a lot of vertical bars of luminance variation that I spent considerable time air brushing an exposure mask to compensate for. I first thought this was due to the polarizer. However, after reviewing most of the skyline images, I am fairly convinced it is more the len's vignette. You can see the vignette very clearly in the single frame from the series I have attached to this post.