Here are samples of images that I created on the morning of 5th March 2011 from Anderson Park.
RAW image capture, Canon 5D MkII, 21MP, on tripod with shutter extension cord, Sigma 80-400mm 1:4.5-5.6 APO, Marumi 77mm DHG Circular P.L.D., Manual Exposure mode, f/8.0 1/10s, ISO400, 175mm 4 overlapping frames in portrait mode, stitched and blended in Photoshop CS5. Embedded colour profile Adobe RGB.
Final cropped panorama 9323×5449 pixels, 350MB TIF ~100x60cm at 240ppi.
Here are the source images in Adobe Camera RAW
You'll note that the histogram is not clipped and has breathing room on the RHS and LHS. If the exposure is increased then the image lightens and clipping of the highlights such as reflection of sunlight on the gold top Eureka Tower takes place. I also like the pink of the sky, which requires the circular polariser to bring out, and this pink colour diminishes in intensity as the exposure is increased.
Here are the four overlapping frames in Adobe Bridge
I actually shot 3 bracketed frames for each image frame (-1EV, 0, +1EV) using autobracketing. Camera mode was M (Manual) after determining what the correct exposure mode was using evaluative metering in the AV mode (aperture value). I don't want the exposure settings to change for each bracketed set! Focus was manual, for the same reason! The exposure brackets give me wider choice in case I have an exposure problem with my default setting and also allow me to create an HDR (High Dynamic range) image if a single frame can't capture the tonal range.
The low light intensity, long lens and requirement to align the autoexposure bracketed set all dictate the need for a tripod. The shutter extension cable prevents me from bumping the camera.
Here are single frames taken at 07:15am and 07:30am
RAW image capture, Canon 5D MkII, 21MP, on tripod with shutter extension cord, Sigma 80-400mm 1:4.5-5.6 APO, Marumi 77mm DHG Circular P.L.D., Manual Exposure mode, f/8.0 1/250s, ISO400, 128mm
RAW image capture, Canon 5D MkII, 21MP, on tripod with shutter extension cord, Sigma 80-400mm 1:4.5-5.6 APO, Marumi 77mm DHG Circular P.L.D., Manual Exposure mode, f/8.0 1/100s, ISO400, 128mm
As you can see, the light in these last two images is BLAH! I lost the golden moment.
Landscape images like this have a large tonal range and also large areas with very subtle changes in tone.
JPEG images have only 256 tonal levels and jpeg furthermore has lossy compression.
RAW data from the camera has many more levels of tone (4096 levels for my camera) and does not use compression.
TIFF files created from camera RAW have 65536 levels of tone (16 bit TIFF).
Working with RAW capture to create 16 bit TIFF files means that none of the data in the original image is lost and gives you great leeway for tonal adjustments.
Embedded colour profile Adobe RGB has a larger colour gamut than default sRGB and is what the quality print shops use.
Suggestion for the workshop:
At various times during the changing light, say at 10 or 15 minute intervals, shoot:
- a single frame using AV mode and look at the histogram for clipping and the image for colour
- exposure-bracketed (eg. -1,0,+1EV) frame using Manual mode using the mid-exposure setting from the first step
- multi-frames overlapping exposure-bracketed (eg. -1,0,+1EV) frame using Manual mode using the mid-exposure setting from the first step
- produce the images that you like the most from all of those that you have created, reduce them to maximum dimension 1024 pixels JPEG sRGB profile – sorry! that's what the web uses, and mail them to me with comments for posting on the Class Images web page. I will comment and welcome comment from others as well as the helpers.
Enjoy the workshop, Barney