Gudies: HDRIs from Scratch

source/conf.py

@@ -170,8 +170,7 @@
 
     'globaltoc_collapse': True,
     'globaltoc_includehidden': True,
-
-    'navigation_with_keys': False
+    'navigation_with_keys': False,
 }
 
 # -- Options for HTMLHelp output ---------------------------------------------

source/guides/hdri-creation.rst

@@ -0,0 +1,201 @@
+:author: Jake G. Water
+:date: 2020-04-19
+
+=================
+HDRI From Scratch
+=================
+
+.. topic:: Pre-Requisites
+
+   #. :guilabel:`Optional` :doc:`sekonic-camera-calibration`
+   #. :guilabel:`Optional` :doc:`lighting-ev-primer`
+
+.. topic:: Lesson Plan
+
+   #. Required Equipment
+   #. How to Captue in the Field
+
+      #. Choosing a Spot
+      #. Light Meter Measurements
+
+         #. Estimating Light
+
+      #. Camera Settings
+      #. Calibration Photos
+      #. Brackets
+      #. Extreme Light Sources
+
+         #. The Sun is Very Bright
+
+      #. Second Calibration Photos
+
+   #. Processing Raw Photos in [CaptureOne]_ and [ColorChecker_Camera_Calibration]_
+   #. Stitching Using [PtGui]_
+
+Equipment
+=========
+
+#. Canon EOS 5D Mark III
+#. Magic Lantern
+#. Tokina SD 17-35 F4 (IF) FX
+#. Sekonic L-858D-U
+#. X-Rite ColorChecker Passport 2
+#. Tripod
+#. Panoramic head
+#. Nisi 3,6,10-stop Filters and V6 Mount
+
+Equipment Setup
+===============
+
+[Optional] Calibrate Your Light Meter 
+-------------------------------------
+
+See :doc:`sekonic-camera-calibration`
+
+Removing Parallax
+-----------------
+
+* https://www.bhphotovideo.com/explora/photography/tips-and-solutions/tools-of-the-trade-for-panoramic-photographers
+
+Capturing
+=========
+
+Choosing a Spot
+---------------
+
+Light Meter Measurements
+------------------------
+
+We are going to import these haris into our Unreal environment later.
+The more explicit light measurements we have about the scene the better.
+This will help us choose the right settings on the unreal side to make the lighting match.
+
+Estimating Light
+----------------
+
+Before setting up your camera, you need to profile the light of your scene.
+This includes every light source, in every shadow.
+You want to get an idea of the brightest light and the darkest dark, in order to ensure that your brackets capture everything.
+
+For some things, you can just point your light meter at it and read the value directly.
+The light meter will tell you what camera settings you need to use.
+
+Your camera can also tell you if anything in the scene is clipping.
+Take a few test photos with the recommended settings from your light meter, and look to see if anything is clipping or underexposed.
+Ten to fifteen minutes now will save you a lot of time later.
+
+Estimating the Sun
+^^^^^^^^^^^^^^^^^^
+
+If you have strong enough ND-Filters, at least 19 stops, you can probably capture the sun directly.
+There are few ways to indirectly estimate the intensity of the sun.
+
+.. danger::
+
+   **Do no look at the sun directly, especially through a viewfinder or the light meter.**
+
+If not capturing directly, you can use one or more of the following approaches.
+
+#. Take an illuminance (*lux*) reading with your meter, pointed at the sun. Multiply the lux value by 13,000.
+#. Estimate from your 18% gray card.
+
+   Position your grey card directly facing the sun.
+   Take a luminance reading (*cd/m2*) of your gray card, and use the formula
+
+   .. math:: L_{sun} = 13000 \frac{L_{card}}{0.18}\pi
+
+#. Guess using charts.
+#. Use :math:`1.6e9 cd/m^2`
+
+Calibration Photos
+------------------
+
+Brackets
+--------
+
+Using magiclantern, the camera can take 12 bracketed shots from a single press.
+
+- Set the camera to take 12 bracketed shots
+- Set the bracketing order to ``0, +, ++``
+
+This will bracket the shots in increasing order, which will make it much easier to view when you are examining four hundred photos later in the file explorer.
+You will have to set your camera to begin taking photos at the most-underexposed setting.
+
+- Lock the shutter up, to prevent excess wobbling and wear.
+- If you don't have a remote trigger, use the 2-second countdown to trigger the shutter.
+
+
+
+Extreme Light Sources
+---------------------
+
+Equip your ND filters, try not to move the camera.
+
+.. warning::
+
+   Do not change any bracketing settings. Add the filters only. PtGui will get upset if the bracketing values change and refuse to create your HDRI.
+
+
+The Sun is Very Bright
+^^^^^^^^^^^^^^^^^^^^^^
+
+If you plan on capturing the sun directly, the camera needs to be able to catpure 33EV.
+From [Wiki:EV100]_ given :math:`N` as the apeture and :math:`t` as shutter speed, then EV can be calculated as:
+
+.. math:: EV = \log_2 \frac{N^2}{t}
+
+Or reversing that with :math:`EV=33` and apeture f/8 we get:
+
+.. math:: t = \frac{N^2}{2^{EV}} = \frac{1}{134217728}
+
+That's an impossible shutter speed. Even for f/32 we would need a shutter speed of 1/17747798.
+There is no way to capture the sun without *very strong ND filters*.
+For f/8 and 1/8000 shutter speed, a camera can capture EV18.96, thus we need 33-19 = 14-stops of filters.
+
+The NiSi filters provide 10, 6, and 3 stop filters which can be stacked giving a total of 19 stops, *perfect*.
+
+.. [Wiki:EV100] https://en.wikipedia.org/wiki/Exposure_value
+
+Second Calibration Photos
+-------------------------
+
+Post-Processing
+===============
+
+Processing Raw Photos
+---------------------
+
+PtGui can process most Raw files directly, but as an option we can use [CaptureOne]_ to apply an calibrated ICC profile to the Raw files and save them as 16-bit TIFFs.
+
+.. sidebar:: Generating an ICC Profile
+
+   .. raw:: html
+
+      <iframe width="100%" src="https://www.youtube.com/embed/FxW7tN6FNh0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+
+#. White balance using your calibration photo. You can apply this to all further Raw files.
+#. Crop and extract the calibration photo of your color chart, after white balancing. 
+
+   #. Apply an empty ICC profile
+   #. Export as a 16-bit TIFF with embedded ICC profile.
+
+#. Use [ColorChecker_Camera_Calibration]_ to generate an ICC profile.
+#. Back in CaptureOne, apply white-balance, and the generated ICC profile to the 300+ bracketed shots of your HDRI. Stay in linear space.
+#. Export as 16-bit TIFFs.
+#. Use these TIFFs in the next section.
+
+
+Creating the HDRIs
+------------------
+
+#. Drag all your bracketed shots into PtGui.
+#. PtGui should recognize that your are trying to create an HDR photo and offer go group bracketed photos.
+#. Adjust the EV for any brackets which had filters applied to them.
+
+.. [PtGui] https://www.ptgui.com/
+
+   PtGui Pro is required for stitching HDRIs
+
+.. [CaptureOne] https://www.captureone.com/
+
+.. [ColorChecker_Camera_Calibration] https://xritephoto.com/ph_product_overview.aspx?ID=2632

source/guides/lighting-ev-primer.rst

@@ -0,0 +1,49 @@
+:author: Jake G. Water
+:date: 2021-04-20
+
+==================
+Lighting EV Primer
+==================
+
+.. topic:: Lesson Plan
+
+    #. Just enough background to get started.
+    #. Review the math, units, and formulas.
+    #. What is EV100?
+    #. Around the work real light values.
+
+       #. Indoors
+       #. Outdoors
+       #. The Sun
+
+Background
+==========
+
+Maths
+=====
+
+Calculating Luminance from Illumination
+---------------------------------------
+
+Calculating Illumination from Luminance
+---------------------------------------
+
+.. math:: \Omega = 2\pi(1-\cos(\theta))
+
+.. math:: E_t = \Omega L_s
+
+.. math:: L_t = \frac{E_t}{\pi}
+
+
+EV100
+=====
+
+EV100 from Illumination
+-----------------------
+
+EV100 from Luminance
+--------------------
+
+Real World Values
+=================
+

source/guides/sekonic-camera-calibration.rst

@@ -0,0 +1,21 @@
+:author: Jake G. Water
+:date: 2021-04-20
+
+==========================
+Sekonic Camera Calibration
+==========================
+
+.. topic:: Lesson Plan
+
+    #. Guid https://www.sekonic.com/sites/sekonic.com/files/datatransfersoftware_guide_en_d75_1022.pdf
+    #. https://www.sekonic.com/support/downloads/L-858D-U, https://www.sekonic.com/support/downloads
+    #. Canon 5D Mark III
+
+       #. Set ISO to 100. https://www.dxomark.com/Cameras/Canon/EOS-5D-Mark-III
+       #. Incident Light Reading
+       #. Reflective Light Reading of Grey Patch
+       #. Measaure Evennes of light
+       #. EV0 pic, EV+3/-3 pics.
+       #. Sitch Together Using [SekonicDataTransfer]_
+
+.. [SekonicDataTransfer] https://www.sekonic.com/exposure-meters/l-858d-u