Exercise: Histogram

Aim
The aim of this exercise was to increase familiarity of histograms. I sometimes check the histogram on the computer when reviewing images, and occasionally do so when shooting, but it's not something I do too regularly - I tend to rely more on how the image 'looks' rather than what the numbers tell me. Nonetheless, it's useful to become familiar with histograms and in particular, to be aware when the data is being clipped - either at the shadow or highlight end of the spectrum.

Software comment
I have been somewhat delayed in finishing this exercise (and also working on the first assignment) because I have built a new computer and installed Lightroom 4 for the first time. I've had it up and running a few days now and it's quite different to DigiKam which I used previously. It will be a bit of a learning curve, but I feel that it's an appropriate time for me to be upgrading to industry standard software. So this is the first exercise I am using Lightroom 4 for.

Low Contrast Scene
For my low contrast scene I have chosen a fairly bland view of the base of a large tree, with grey rocks and dirt  in the foreground. It is not particularly inspired, but fits the brief!

Correctly exposed, Low contrast image with histogram

-1 stop EV, Low contrast image with histogram

+1 stop EV, Low contrast image with histogram

For these three low contrast images, the histogram shows a fairly uniformly triangular shape. For the 'correctly' exposed image, the triangle is roughly centrally located. For the -1 stop EV 'underexposed' image, the triangle is pushed to the left, and for the +1 stop EV 'overexposed' image, the triangle is pushed to the right. None of these images has the 'wrong' exposure though, they are just variations depending on what I want the scene to look like (medium grey for the 'correct' exposure).

Average Contrast Scene
For my average contrast scene I have chosen a view over the Brisbane river with buildings, sky and river.

Correctly exposed, Average contrast image with histogram

-1 stop EV, Average contrast image with histogram

+1 stop EV, Average contrast image with histogram

 For these three average contrast images, the histogram shows a flattish, spread out shape. For the 'correctly' exposed image, the distribution is roughly centrally (slightly left) located. For the -1 stop EV 'underexposed' image, the distribution is pushed to the left, and for the +1 stop EV 'overexposed' image, the distribution is pushed to the right. All three images have some 'shadow warnings', as indicated by the triangle shown top left on the histogram. This displays in blue on the image when the mouse is hovered over the triangle. An example is shown below:

-1 stop EV with shadow warnings highlighted in blue

The shadow warnings are useful for highlighting where an image is being clipped at the low end. This means data is lost effectively, and no amount of post-processing will get any detail back in these parts of an image. I sometimes use the functionality on my camera to check for clipping when I am out shooting so that I can adjust my exposure or lighting if necessary to avoid excessive clipping.

High Contrast Scene
For my high contrast scene I have chosen a view looking up at a large tree, with large areas taken up by branches, and light filtering through the foliage.

Correctly exposed, High contrast image with histogram

- 1 stop EV, High contrast image with histogram

+ 1 stop EV, High contrast image with histogram

For these three high contrast images, the histogram shows a non-uniformly distributed bimodal shape spread across the whole spectrum. For the 'correctly' exposed image, the distribution is mostly located on the low end, with a spread of values all the way to the far high end. For the -1 stop EV 'underexposed' image, the distribution is pushed to the left, but still with some values all the way up to the high end, and for the +1 stop EV 'overexposed' image, the distribution is pushed away from the low end with more values at the highest end. The -1 stop image has some 'shadow warnings', mainly on the fringes of the tree and leaves. The 'correct' and +1 stop images have 'highlight warnings', as indicated by the triangle shown top right on the histogram, mainly in the sky. This displays in red on the image when the mouse is hovered over the triangle. An example is shown below:

+ 1 stop EV with highlight clipping warnings shown in red

The highlight warnings are useful for showing where an image is being clipped at the high end. This means data is lost effectively, and no amount of post-processing will get any detail back in these parts of an image. I sometimes use the functionality on my camera to check for clipping when I am out shooting so that I can adjust my exposure or lighting if necessary to avoid excessive clipping. Highlight clipping can be particularly bad in skies, when a graduated neutral density filter can be used to decrease the dynamic range of the image. 'Control the highlight's', or 'expose for the highlights' are good mantras for digital photography (interestingly, I understand it is the opposite for B&W film photography, where it is better to slightly overexpose, and control for the shadows). 

Summary
This exercise is good for increasing awareness of histograms but more importantly, exposure and how to correctly expose images, which I believe we get to more in the next chapter.

QCP visit, March 24th, 2012

A visit to the Queensland Centre for Photography in my lunchbreak on Friday.


A couple of artists that caught my eye are listed below, and I have found their own websites to link to.

Scott Howes - Link here. Backpacking / roadtrip style images across Central Australia, with deep saturated colours, long shadows and stunning clouds and sunsets to match. Feels like a road-trip, with images from inside the van/car etc included.

Scott Howes, taken from QCP website for personal study purposes

Prudence Murphy - Link here. Watching children play, ... with toy guns ...  Interested in childs play and learning about interacting with the world around them.

Prudence Murphy, taken from QCP website for personal study purposes

Leanne Sauer - Link here. Disturbed series of still-life images which form metaphors for personal (complex) relationships. Not pretty... but as a series, very evocative and questioning of what relationships mean and how society views and expectations are placed on us all.

Leanne Sauer, taken from QCP website for personal study purposes

Notes from QCP visit

Notes from QCP visit

References:

Howes, S (2012), QCP Two days till Saturday. Online, available at: http://www.qcp.org.au/exhibitions/current/album-693/28  [accessed 24 March 2012]

Murphy, P (2012) Prudence Murphy Photography. Online, available at: http://www.prudencemurphy.com/ [accessed 24 March 2012]

Murphy, P (2012), QCP Boys with Guns Online, available at: http://www.qcp.org.au/exhibitions/current/album-694/28 [accessed 24 March 2012]

Queensland Centre for Photography (2012) Website. Online, available at: http://www.qcp.org.au/ [accessed 24 March 2012]

Sauer, L (2012) Leanne Sauer Photography Online, available at: http://leannesauer.com/ [accessed 24 March 2012]

Sauer, L (2012), QCP Committed Online, available at: http://www.qcp.org.au/exhibitions/current/album-695/28 [accessed 24 March 2012]

Exercise: Editing

I am using the images shot for Exercise Workflow 2 for this exercise, shot at the Coorong. I started with 226 images which all cover the same location. Within this set there are a number of sequences of images exploring the same subject, trying to improve, as recommended in the course notes. I downloaded the images to my computer using a card reader. These were placed in folders:

JPG files : Photos/DPP_1/Part_1_Workflow/Workflow_2_Editing/

RAW files: Photos/DPP_1/Part_1_Workflow/Workflow_2_Editing/cr2

At this stage of my learning process, I work mainly with out-of-camera JPGs.

Step one - the technical edit

A folder was placed in Workflow_2_Editing called /delete.

I star all images 1 star, and then go through assigning zero star rating to all images I don't like, for example, camera shake, obvious massive under/over exposure, repeat images that are the poorer version, etc etc. This is of course quite a personal process and very subjective. I do this with DigiKam software, with the setting at full-screen to maximise the viewing area of the images.

All zero star images are placed in the /delete folder (and corresponding RAW files). These are reviewed at a later review session and then deleted once I'm happy with my choices. This saves on disk space and makes viewing of the better images thus more enjoyable.

At this point I also tagged all my images,  though I'm still a little unsure of how best to do this. 

Step two - the selects

This left 157 images with one or more stars, all technically OK, example below.

Example of images with one or more stars, the result of the technical edit.

Again at full-screen setting, I review the images and apply various star ratings:

0 star = move to /delete folder

1 star = low potential

2 star = moderate potential

3 star = good potential

4 star = definite best images to edit

At this stage I just used 1, 2 or 3 stars.

Step three - the first selects

At this point of the process I had 11 images with 3 stars. These are my first selects (displayed below) and I made a brief note in the 'comments' box to explain why I liked each image.

11 images with 3 stars. Comments added to each image.

Step four - group and review

I stopped working and came back later, and reviewed all my choices. I was happy and did not make changes to my first selects this time.

Step five - a final choice

I then displayed just my first selects and went through to choose my final two images to process and present. I did this by viewing in full screen mode and simply choosing those two images I liked the best, and gave them both four stars.

The first image I chose because I liked the strong shadows, simple setting and the 'country' feel the image has. The colours are muted and simple, and I felt like the whole image just worked.

The second image I chose because I wanted a view of the actual coorong water and decided I liked the texture of the grasses in the foreground. The DOF (from using f/22 with a 24mm focal length) is large enough to capture most (all?) of the image in focus which is important for landscape images like this one. The colours are strong, and vary across the image, with the shadows, and obviously show the time is late in the day. More birdlife on the water in this image would have added to it, but I felt overall it was a stronger image than the others in my set.

Post-processing of final choice images

My workflow from here was to take the two images into Photoshop CS2 and edit them there. I followed roughly the same sequence for both, detailed below:

1. Open .jpg file in Photoshop

2. Change resolution (300 ppi), and size (to 18 x 12 inches)

3. Save as new file, in tiff format, and with extension _18x12_001.tif

4. Create a copy of the background layer

5. Check colour balance and adjust if necessary (not required for these two images)

6. Apply levels/curves as layers to whole image, when using levels use the 'alt' key to see impact. Adjust opacity to curves to decrease impact.

7. Localised editing. In this case, Image 1 did not require any - the dirt is real and on the wall, and thus was not removed. For Image 2, I did some spot healing and cloning for minor marks in the sky, possibly dust spots that have been hard to remove on the sensor (which I cleaned prior to my holiday). I zoom right in to 100% for this process, and also make sure I zoom right out to view the whole image to make sure any retouching is subtle and not seen in the final image.

8. Crop as necessary. In this case, only Image 1 was cropped a little to slightly reduce the dark shadow area at the bottom of the image.

9. Unsharp mask

10. Save as both a tif file (to keep layers) and jpg file (flattened).

I am in the process of learning about Photoshop at the moment, both through an evening course and also reading 'Evening, M, 2005, Adobe Photoshop CS2 for Photographers, Focal Press, Oxford', so my workflow will hopefully develop as I learn more.

The final two images are displayed below.

Table against wall

Coorong; Grasses and water at sunset

My notes in my logbook are presented below:

Logbook Notes, Editing

Logbook Notes, Editing

In conclusion, I already had some kind of editing process, but it was good to formalise it through this exercise. I will continue to use this system in future projects. I want to learn more about tagging images (keywords etc), which I will try to do some reading on. I will also continue my reading and learning more about post-processing which is an important part of the modern digital workflow.

Exercise: Your own workflow 2

The aim of Exercise: Workflow 2, is to devise a workflow for a specific shooting assignment that is longer in length than the one in Workflow 1, and will thus involve a larger number of images. I shot 226 images while visiting family at the Coorong, which is a natural region South of Adelaide, whilst visiting recently.

Pre-Shoot and Shoot:

My pre-shoot and shooting plan is displayed below:

Workflow flow-chart, Preparation and Shoot

I chose to use my Canon 30D for the shoot, and brought two lenses along, with matching filters (polarizer, neutral density etc). I had my tripod with me but did not take it out on every shooting session. As this was a landscape shoot, all light was natural, and the time of day very important. I did almost all of my shooting in the two hours before sunset, though I did take a couple of photos in the middle of the day, and some in the afternoon for contrast. I varied my camera settings depending on subject, light availability, time of day, and whether I was using my tripod or not.

I was not able to edit any images during the shoot as I didn't have a laptop with me. I did however review on camera after each session and made adjustments to my plan for the next session (for example, I took my tripod down on the second evening so I could use smaller apertures and increase my DOF). In terms of variations to the above workflow, I accidentally left the cable for the battery charger in my bag left in Adelaide. Fortunately it's just a kettle lead so I could borrow one relatively easily. I only deleted a few images during the shooting sessions, as review on the back of the camera is not ideal.

Post-Shoot:

My flow chart is displayed below:

Workflow flow-chart, Post-Processing

I followed the flowchart above fairly closely. After reviewing my images initially, I ended up with 157 images with one or more stars. All zero star images were moved to the /delete folder, and deleted later after a second review. I performed the starring process over a number of sessions in order to adequately review and 'step back' from the process, which I find very useful. All starring sessions were performed with Digikam set in full-screen mode, to maximise the space the image takes up on the screen. I will write more detail about the editing process for these images in another blog, for the Editing Exercise.

I then determined I had 11 images with 3 stars. They are shown below:

Images with 3 stars.

I then chose two images which were processed further in Photoshop to represent my visit to the Coorong. They are displayed below.

Table against wall

Coorong; Grasses and water at sunset

My post-processing workflow is in the midst of change. I am going to night classes once a week to learn more about photoshop editing, and applying these learnings to the workflow I used on the images above. I will write more about that in Editing.

My notes in my logbook for this exercise are shown below:

Notebook for Workflow 2

In summary, I followed my flowchart more closely for this exercise, as I incorporated the learnings from the previous exercise. Reviewing during the shoot enabled me to improve my images and to leave with a wider variety of images than had I just one out once. 

Bob Carey Photographer

Aline Smithson has a blog called L E N S C R A T C H which I follow, and this recent post stood out to me. In short, it's a personal project that started as just that, but has become a fundraising project for breast cancer research. It's an example of charitable photography but with interesting, quirky images.

The photographer, Bob Carey, obviously knows his stuff, from looking at his website. His portraits look casual but I suspect are perfectly planned. I wonder if they are mostly opportunistic (out wandering, targeting people he spies), as the situations look fairly natural. I really like the use of mixed eye contact in the pair portraits. It adds an air of question to the image.  The 'Tutu Project' is unusual and eye-catching, as well as making interesting viewing. All-in-all, an inspired photographer I am glad to have spied.

This image below, for example, is bold, colourful, and simple but yet also making a gently humorous statement at the same time.  The photographer is concerned with social issues, but wants to make them approachable for everyone - he doesn't mind having a laugh at himself which might be a useful skill!

Taken from Lenscratch website for personal study purposes

References:

Carey, B (2012) Bob Carey. Online, available at: http://www.bobcarey.com/ [Accessed 19 March 2012]

Smithson, A (2012) Lenscratch. Online, available at: http://www.lenscratch.com/2012/03/bob-carey-and-tutu-project.html [Accessed 19 March 2012]