PanoTools:
Extended Dynamic Range (was ... first D70/Sigma 8mm panoramas)
Peter Sale 2005-Mar-07 18:52:07
My Nikon D70 can automatically take three exposure bracketed shots. These
shots can be up to three stops apart, that is -3, 0, +3. This morning at
7:15 AM I took three exposures,(-3.0, -1.5, 0.0), 1.5 stops apart, of my
living room, for a total of 16 images. I did not use any flash. I will
attempt to "layer in" the correctly exposed view through my living room
windows, http://tinyurl.com/5aysv, with the correctly exposed interior of my
living room, http://tinyurl.com/4a7ly.
One problem I notice right away is that the detail in some areas of the
window frames of the correctly exposed interior is missing and completely
"blown out" (its not just the view through the windows that is blown out in
this image), while some detail in that window frame is lost in dark shadow
in the image that is correctly exposed for the exterior,
http://tinyurl.com/5aysv. How can I "layer" my way through that problem?
Any ideas and/or suggestions will be appreciated.
So that you can see what I'm talking about, I've uploaded the following
three sample images:
(1) http://petersale.com/temp_stuff/_DSC4013.JPG => correctly exposed for
exterior view through windows and French door. Interior (living room) is
way to dark. (Actually even this image is a bit over exposed for the
exterior. I probably should have used 1/250 sec). f/8, 1/180 sec.
(2) http://petersale.com/temp_stuff/_DSC4014.JPG => an in between exposure.
Not really correct for either the exterior or the interior. f/8, 1/60 sec.
(3) http://petersale.com/temp_stuff/_DSC4015.JPG => correctly exposed for
interior of living room. f/8, 1/20 sec.
Remember that above images are 1.5 stops apart, -3.0, -1.5, 0.0. Even at
7:00 in the morning, the exterior is at least three stops brighter than the
interior!
Notice that even though (3) is more or less correctly exposed for the
interior, the areas around the French door and the window frames is blown
out. That is, in addition to the through the glass view being completely
blown out, a hard to select portion of the interior is also blown out.
Except for this issue I could fairly easily "layer" in the corresponding
areas (window and door views of exterior) from image (1) into image (2).
Any suggestions on how to better accomplish this "layering" task would be
greatly appreciated?
BTW, yes I know the White Balance (WB) is off. But the WB for outside will
be direct sunlight, while the WB for the interior would be, say, shadow or
cloudy or incandescent? In any case, I expect this layering approach would
also quite nicely deal with two different WB settings, one indoors and one
outdoors. I imagine this would be automatically dealt with via the exposure
"layering" approach?
Regards/Peter
--
Robert Eller replied:
Hi Peter,
my personal experience has been that I need to take multiple exposures which
also include a few images taken with flash. I do tend to do PS blending work
using a base image and layering in various elements of the other exposures
for effect. At present, I've found no "real" alternative. If anybody has
another workflow model that will generate the required images.... well I'm
all ears. ;-)
--
Peter Sale wrote:
The flash, an SB-800 set at 1/2 power, was attached to the hot shoe on my
D70, full wide angle, and pointed straight ahead and a bit up, towards the
ceiling. A sample image can be viewed at
www.petersale.com/temp_stuff/1.jpg
.
I suspect flash would not work well in a room filled with items that would
cast shadows or even in a larger room because as you might know, only the
"subject" that is a specific distance from the flash, say ten feet, is
correctly exposed. Everything closer then 10 feet would be a bit over
exposed and everything more than ten feet would be a bit under exposed.
I'm experimenting with shooting interiors very early in the morning, say
6:30 or 7:00 am or late in the afternoon, say, 4 or 4:30 pm, so that the
dynamic range between the interior and the exterior, as seen through the
windows, is not so great. The problematic alternative involves shooting
multiple exposures of the same scene and blending them together to get
greater dynamic range. I have not had a lot of luck with that technique
so
far.
Regards/Peter
--
Flemming replied:
Except for some problems at zenith [and perhaps you could do with a
little more light in the kitchen] I think your pano looks good Didn't
think it would be possible for the flash to spread the light enough.
In which direction did you fire the flash?
Do you have an unretouched copy of the shoot, so I can see how the
light spreads?
How do you think the flash would work in a not so white room and/or
with more objects around the room at "eye" height [casting shadows]?
Best regards
Flemming
--
> Peter Sale wrote:
> Yes, I know I'm not supposed to use a flash but I wanted to capture
> the extended dynamic range of both the "dark" interior of my living
> room and the "bright" exterior view through the windows without
> attempting to merge multiple exposures. Put differently, I did not
> want to deal with more than four images.
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