High Dynamic Range Images or HDRi is a
completely new photography technique that is used to extend the exposure
range of a camera. Fhotoroom HDR provides the widest and most powerful
selection of tools to take multiple exposure from a camera and align,
merging, tone map and post process till your HDR is perfect.
To begin this tutorial it is assumed that
you have a basic understanding of what HDR images are. If that is not the case, please read What is
HDR tutorial. In addition, for this tutorial you need several
photographs of the same image at different exposures (preferably
using a tripod). If you don't please feel free to login
and use any of the free photo sets available in the Fhotoroom group.
The first step in creating an HDR image is
selecting your source photos which are simply a scene photographed at
different EV levels with the fstop locked, if the fstop is allow to
change then it will prevent the image from aligning properly. This is
because each fstop distorts the image slightly differently giving a
different DOF or depth of focus.
HDR Exposure Selection
To begin you first open the "Generate HDR Image..."
tool in Fhotoroom located under the menu option called "HDR's".
The window below appears and is the place where you define all the
properties for creating your HDR image. It is highly recommend to always
select the "Automatically align source photos", beyond that is
very dependent on the scene that was taken and how it was taken. Shots
take with a tripod probably don't need any auto alignment let alone
rotation issues. The "Use Slow Method" is simply a slightly
more complex method of auto alignment and can usually align photos that
can't with the simpler method. The "Use Region for Auto
Alignment" option allows the user to define an area (by selecting
an area in the photo) in the image to focus alignment on, which is very
useful for shots with a lot of distortion.
Usually the next scene after this one is the
Manual Alignment override window, which shows you exactly how well Fhotoroom
aligned the photos and then correct if necessary. Users can now
by pass this window completely by selecting the "Bypass Manual
Alignment Correction" option.
Now that the Alignment options have been
selected users can define how they would like the merging to be done,
with options such as creating an hdr file when needed, creating an hdr
that are precise in luminosity values which important for Image Based
Lighting in the 3D industry, Reduce Micro Noise, Reduce Ghosting which
can occur when object, trees or people move between exposures and lastly
Reduce Highlight Grey Areas.
There are 2 very important things to consider
here, using the Ghosting option reduces the overall dynamic range of
your hdr files which results in less detail and secondly the Reduce
Highlights Grey Area should be selected if more than one exposure has
very bright object such as the sun, lights and so
Manual Alignment of Photos
If you choose to make additional manual corrections and wish to see how well the
photos have been aligned, you select any photo other than the first photo on the list which is considered the
master photo (the photo by which all other photos are aligned to).
Once selected the Alignment Preview Window gets updated
with the new layer. To correct any misalignment, scrolling the up/down
arrows of x Shift and y Shift slider options allows for pixel accurate
correction. To make this process as simple and precise as possible,
users can move the image position, zoom in and out and adjust the
opacity of the image layers to allow for easier comparison. The opacity
has no effect on the final result and is only used to help with
To see all the information related to each image you can scroll the
image list to the right and see, fstop, exposure time, (x,y,a) alignment
as well as image ranking or select each file individually.
Image List Checkbox
The Checkbox option beside each
photo allows users to unselect any photo(s) they don't like or can't align properly before merging to the final
(X, Y, A) Precession Alignment & Auto Alignment
The X, Y and A alignment options allows the users to align the images to a
master image before applying the hdr merge. The first image of the list is
always the master image, and the order of the list presented has no effect
as everything is ordered during the merging process.
The Freehand option was included in order to enabled users to align images in the
same manner that you would move layers around in Fhotoroom. To utilize this
option you require to check off the Freehand checkbox located to the
right of the Alignment Tools title. Once finished, this box can simply
Step by Step
Goto HDR's | Generate HDR Image... menu
Once the "HDR Exposure
Selection" window is open, click the
Select the files you want to use to create your hdr image.
Select your Auto Alignment and
Merging options, highly recommend always have Auto Alignment
Click Apply button. If
the Bypass option was selected skip to step 8.
If you feel the misalignment was significant enough,
and your image requires additional manual correction, then select each
photo one by one and using the Hand, Zoom, and Opacity tools verify each
photo's alignment. If you believe there maybe a misalignment, adjust
the x Shift and y Shift values until the layer is properly
positioned. This information is preserved in the Image List, which
can be seen by scrolling the Image List to the right.
Click the Apply button to begin the merging
Once your merging operation is
completed, Fhotoroom will ask if you want to Tone Map your image
now. If additional editing is required before tone mapping simply
select "No" and you will be able to tone map your image
anytime using the HDR's | Tone Mapping... menu option. Once you are happy with your results you can save the image in any
format available in Fhotoroom, either HDR or LDR formats.
Single File Tone Mapping
If you want to tone map a single jpg or raw file, simply
load your photo into Fhotoroom and not into the Merge to HDR tool and then
proceed directly to the HDR's | Tone Mapping... menu option and Fhotoroom
will do the rest for you.
Goto File | Open... menu option.
Once file has been loaded goto HDR's | Tone
Mapping... menu option.
If the file was one of the hdr file formats the Tone
Mapping preview tool will automatically load. If the file was any
other file format like a camera RAW or jpg, a popup option will load
asking if you would like Fhotoroom to prepare this file by converting it
into the hdr color space which is required for tone mapping. Once you
click Yes, Fhotoroom will then load the Tone Mapping window.
To learn more about tone mapping you image go to our Tone