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HDR
HDR
(high dynamic range) is a term describing a set of techniques that
expand the dynamic range
of luminance between the lightest and the darkest area of an image.
Does that sound confusing? Ya - it does ...
OK -
say you are out at dusk (or dawn) and see this amazing landscape scene
that just begs to be photographed - it's a potential prize winner!
The
only problem is the huge dynamic range of the scene - the number of
f-stops between the lightest and the darkest parts of the scene you
want to accurately capture with your trusty digital camera.
This
gorgeous landscape may have a range of 15 to 20 f-stops while your
digital is only capable of capturing 8 to 10 f-stops so something has
to give. Either the shadows will be blocked out or the
highlights
will be blown out.
By using high dynamic range techniques you can more accurately
capture what
was visible in that scene than you can with a normal
digital image.
This is what I'm talking about ...
The following images were
taken just before sunset and while all of them are acceptable, not one
of them accurately captures what was visible with the naked eye - the
emotional content has not been recorded.
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The shot as metered.
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One f-stop below the metered value. |
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One f-stop over the metered value. |
What we need to do is combine these three images into one
super shot - and that's exactly what High Dynamic Range does and here it is ...
After completing the merge process you will generally find that some
additional editing in your favorite digital editor is required - things
like levels or curves, maybe some sharpening. You can even get
into the image with a soft light layer and do some dodging and burning
with your Wacom pen.
What
I've Learned About High Dynamic Range (so far)
Here's what I've learned about High Dynamic Range
photography -
so far ...
- Multiple images of the exact same scene taken one
right after the other are necessary to do the conversion which means ...
- You need a camera that's capable of taking at least
three Bracketed
shots with different Exposure
Values (EV) which probably
means
you need a Digital SLR but there are a few high end Point and Shoot
cameras that will take Bracketed shots.. Check your
camera manual if you are not sure.
(Terry of Terrys Tutorials adds - the best
aperture is about 3 stops down from the maximum stop - so for an f/4
lens - f/11 is about best - the exposures should be set so that in the
darkest one there is detail in the highlights AND in the brightest one
there should be detail in the shadows - THEN you have the true range
available.)
- The shots should be taken with the camera set to Aperture
Priority (which means the Aperture is set to one opening
-
say f 8.0 for example - and the shutter speed changes - the Aperture
that is set is given Priority and the shutter speed will depend on what
the camera light meter reads). Aperture Priority is generally indicated
by the letter A or Av
on the camera's selection dial.
The
reason for setting the camera in Aperture Priority is that
the aperture will remain the same for the three shots and
always
have the same
depth of field.
(Additional comments from Terry - because the various auto
functions in a camera can change each others' settings you are best
setting the focus to manual AND setting the vibration reduction OR
image stabilisation to OFF and setting the flash to OFF AND
setting the ISO to the base level AND setting the white balance to a
setting of your own choice otherwise the merge functions in say PSP
will not do the job properly. The more complex the image the more
critical these settings become.)
- The camera should absolutely be mounted on a good,
sturdy tripod. Any motion of the camera during the bracketed
shots will cause problems during the conversion stage.
I took
three lovely shots of a water sunset with some boats in the foreground
and somehow the camera jiggled, darn. If there's a mistake to
be made rest assured I will make it but that's how we learn - we
learn more from our mistakes than from our successes.
Don't
want to carry a bulky tripod everywhere? How about investing
in
one of those cool Gorilla Pods that will wrap their arms about things
and hold your camera steady or ...
As a last resort simply jam your camera
up against something that doesn't move, lean into it to keep it
motionless and take your shots. Maybe do two or three
sequences
to insure that one set has no motion.
(Terry's final thought - not only is a tripod essential but some
authors advise a remote shutter release because even the slightest
movement in the images sequences can confuse the merge.)
- The subject matter needs to be perfectly still
because any motion will be visible when the three shots are combined
with your software.
And that's only the set-up!
Those five points lead to one conclusion and that is - converting to
HDR requires some planning.
The High Dynamic Range Debate
Some folks love High Dynamic Range photographs, some hate it and the debate rages
on. Over the past month or so Terry (Terry's Tutorials) and me have
been trading emails about HDR. Terry sent me a couple of links
looking at both sides of the High Dynamic Range debate.
These are articles written by
Pro Photographers espousing both points of view for your reading
pleasure ...
Why I Don't Do HDR
Why I Do HDR
Practical Photography Tips
 This
is a fabulous site your just have
to visit for photography tips to create wonderful images for HDR
conversion.
Breathtaking vistas, beautiful sunsets and sunrises, the contrasting
textures and colors of fields, whatever the place there is something
special about capturing the beauty of creation through landscape
photography.
High Dynamic Range
Planning
High Contrast Scenes
- the human eye is capable of seeing a very large range of brightness
(dynamic range) - some say it's in the range of 20 f-stops.
Your digital camera can see and record about 10 f-stops.
If
the scene you are shooting includes 17 levels of
brightness and your
camera can only record 10 of them how do you think the picture
will look?
It will probably be OK but with either blown out highlights or blocked
shadows and you don't want that, do you?
For example, have you ever seen something that absolutely had to be
photographed because it was so beautiful or unique only to suffer great
disappointment when you downloaded the picture?
Sure you have, we've all had that experience.
The dynamic range of that particular scene far surpassed the dynamic
range capability of your camera and something gave.
High contrast scenes can include but are not limited to ...
- Early morning
- Early to late evening
- Sunrise and sunset
- City scapes
- Landscapes
- Beach scenes
- Snow scenes
Pretty much anything that has a high contrast is a good candidate for
HDR.
If you're looking for tips to help improve your outdoor photographs
then check out this site ...
Digital
Photography Basics for Outdoor Enthusiasts!
Follow the tips, techniques and tutorials in this site to shorten your
learning curve and start creating better photography immediately!
Camera
Set-Up
Bracketed Exposure
The camera set-up will vary from camera to camera.
My six year old Olympus
E-300 will take 3 bracketed shots ranging -1 EV to 0 to +1
EV (EV = Exposure Value).
Newer and more sophisticated cameras generally have a wider bracketing
range, for instance ...
- Canon 50D -5.0
EV to + 5.0 EV
- Sony
Cyber-shot DSC-WX5 -2.0 EV to +2.0 EV
- Olympus
PEN E-P2 -3.0 EV to +3.0 EV
- Nikon
Coolpix L110 -2.0 to +2.0 EV
- Panasonic
Lumix DMC-G10 -3.0 EV to +3.0 EV
- Samsung
TL 205 -2.0 EV to + 2.0 EV
So
I guess when my Olympus E-300 was new, -1 EV to +1 EV was
probably
about as good as it got - not now - and that would explain the reason
that it's difficult to get three files with a wide separation of
brightness between them.
If your camera will do 2.0 EV or 3.0 EV steps then use the highest
setting to get the greatest range in the images.
Manual Setting
The images needed to produce an HDR image can also be shot using the
Manual Mode of your camera.
In
this situation just set the Aperture, determine the best shutter speed
to produce a good image and then change the speed for each exposure and
you can pretty much set any speed and create multiple images - 4 or 5 -
or whatever you want. In the actual conversion to HDR part
this
will give you lots of creative options.
The only challenge with using the Manual mode is that the camera has to
be touched to change the shutter speed.
With
my Olympus I need to push a button to change from the Aperture setting
to the Shutter setting and then I need to roll a little wheel to change
the speed - all that pushing and turning is not particularly conducive
to keeping the camera absolutely still, is it?
If you want to
try the Manual method you will have to check your camera to see if the
speed can be changed with minimal touching of the camera.
File Formats
If
your camera supports RAW files then that is the preferred format.
RAW files will create the most striking HDR images.
A note
- very few Point and Shoot cameras are capable of shooting in RAW.
Jpeg files can be used as well but they produce less stunning but
overall great results.
Shadows
Highlights
While not a standalone conversion, the Shadow Highlight adjustment in
Photoshop and Photoshop Elements does what you would expect of High
Dynamic Range - it increases the dynamic range of an image.
It's particularly useful with difficult images with either blocked in
shadows or blown out highlights.
Click the thumbnail to learn about the Shadows Highlights adjustment
with Photoshop Elements.
Click the thumbnail to learn about the Shadows Highlights adjustment
with Photoshop.
High Dynamic Range
Software
Photoshop
 Photoshop CS2
included its first Merge
to HDR
function in 2005.
It
has steadily improved over the years and CS5 not only converts multiple
images but it also has a function to create an HDR image from a single
photo.
When everything is said and done it's tough to beat
Photoshop, isn't it?
Photoshop is available for both Windows and MAC.
If you don't already own Photoshop then
the
cost of buying the full package is steep.
Click the thumbnail (or
here)
to learn more about HDR conversion with Photoshop - from CS2 up to the
latest version, CS5.
Paint
Shop Pro
Corel's Paint Shop Pro Photo X3 Ultimate includes HDR Photo Merge ...
 and it does a great
job, at
least in my opinion.
The interface is quite simple to use with only two adjustments
available.
In
terms of bang for your buck, Paint Shop Pro is tough to beat not only
for the HDR Photo Merge option but for the full suite of digital
editing functions as well.
This
image was converted using Paint Shop Pro and then converted to black
and white in the Photo Effects menu. HDR is an
excellent
base for converting to black and white.
The only downside is that Paint Shop Pro is only available for Windows.
Clicking on the black and white image will take you to the Paint Shop
HDR page - so will this link right here.
Photomatix
 In
February of 2003 the first version of HDR software was released by
Photomatix and it is probably the most popular standalone HDR
software.
It's
available in both Pro and Light versions and there is also a
Photomatix
plug-in available for Photoshop.
There are a lot of adjustments in this program and that's
probably why it produces such dramatic results - from mild and natural
to wild and crazy.
Photomatix Pro is not particularly expensive and the Lite version is
even more affordable.
Photomatix is available for both Windows and MAC's.
When I
first became interested in HDR I did a conversion with CS2 and proudly
sent it off to my friend Kandace - an accomplished
photographer.
She asked me to send her the original files.
About 20
minutes later she sent me an High Dynamic Range conversion she did with her copy of
Photomatix. What Kandace sent far surpassed my conversion.
Mine was fine, hers was great - it just seemed to glow and had colors
where mine didn't.
She was using Photomatix and she thinks it is wonderful.
NIK
Software
 A relatively new entrant (October, 2010) in the HDR scene
is NIK Software with HDR Efex Pro.
HDR Efex Pro, is a completely new High Dynamic Range (HDR) imaging
solution designed to help professional and amateur photographers
quickly and easily achieve a full spectrum of HDR enhancements.
HDR Efex Pro overcomes limitations in other software products with a
revolutionary all-in-one approach and multiple tone mapping algorithms
that enable realistic and artistic results to be created
start-to-finish within a single tool.
NIK Software is known for their innovate, effective digital photography
filters with a ton of awards to back them up.
This is a really fabulous program and worth checking out if you are
looking for a complete HDR conversion package.
Click the thumbnail to discover more about HDR Efex Pro.
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Page Links
What
I've Learned so far
High Dynamic Range
Planning
Camera
Set Up
Shadow
Highlight
Software
A Very Brief History
The first recorded attempt to produce a high dynamic range image
occurred in the 1850's by Gustav Le Gray.
In
the 20th century selective dodging and burning of an image produced
results that darkened highlights and opened up the shadows.
Ansel
Adams made this into an art form in his darkroom and selective dodging
and burning is still a very, very useful method to edit an image.
With the
increase in computing power and the introduction of Merge to HDR in
Photoshop CS2 in 2005 creating High Dynamic Range images became a whole
lot easier and available to everyone.
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