DPP Part 1 - Exercise 3 - Histograms

DPP Part 1 - Exercise 3 - Histograms

The purpose of this exercise is to increase familiarity with histograms and to be able to relate each histogram to each image that's been taken.


High Contrast
The screen shot image below from my post processing tool CS6. 

This histogram shows a high contrast image which can also been seen in the histogram with large peaks in the darks, large peaks in the lights with not much between.

Looking at the image itself this can be seen on the contrast between the dark area of the land and the light areas of the sky

The highlight clipping is show in red, and confirms the sub has highlight clipping, and amongst the rocks in blue is shown the shadow clipping

However it appears the the blacks have lost detail as the shadows have been clipped, see left of histogram, elements of "spike" on left hand side are missing / clipped and therefore not captured within image. This could have been resolved by under exposing slightly  Histogram suggests I could move highlights a bit to left e.g. I haven't yet over exposed the image completely, just some parts of sun which you would expect given its luminosity.

The choice can be through exposure compensation to keep detail in shadows or highlights - the photographer's choice.

Low Contrast

This is a low contrast image:

This can be seen in the image with the large expanse of light sky, shown as highlights at right of histogram and little contrast with any shadows or darker areas as would be seen toward left of histogram.

There was no shadow or highlight clipping shown when using these indicators in post processing. This can also be seen in the histogram with space to left of shadows and highlight
confirming no darks and whites in the extremes of the dynamic range

The lack of contrast could be improved post processing in say levels by pushing left hand indicator up to start of darks and the same at other end with lights. Curves could also be used to bring out more detail in darks

Average Contrast

This is an Infra-red image and the image it self shows average contrast with no key darks or lights. This is also reflected in the histogram with gaps at left at right of dynamic range across full spectrum for 0-255

Using the shadow and highlight clipping indicator it confirms no clipping has occurred which can also be seen in the histogram.

The dynamic range in this image can be improved post processing by moving the left and and right hand sliders toward start of darks and lights.


Exercise Learnings

a) Histograms can help confirm the exposure of the image and the dynamic range captured. Viewing this on the back of the camera can allow a better understanding of the exposure at time of shot rather than in post processing. This could suggest to the photographer exposure compensation to say avoid clipping. Its a good habit to review histograms on the camera back on a regular basis

b) Blinkies - Again viewing this on the image on the back of the camera an quickly indicate areas of clipping of highlights or shadows. This may allow the photographer to better understand the image he has captured and perhaps again through exposure compensation adjust the exposure one way or the other. This may allow the photographer to better decide which element of the image he wants to correctly expose e.g. sunsets where land shapes may be wanted in deeper shadows to focus image on sunset colours; portrait type images where faces are under exposed and features lost or darkened due to the camera expsoure for sky or scene behind face

c) In post processing using levels where images have a dynamic range not fully end to end across the 0-255 scale by moving the sliders the start and end points can be reset spreading the exposure across the scale end to end

d) Post processing changes can allow "fixing" of images but use of the histogram and blinkies on the camera back can allow exposure changes by the photographer at location - always better to capture the image correctly in camera than to rely on post processing

e) I feel reasonably knowledgeable to make changes in levels based on the histogram I need to do research on how to correctly use curves

f) I need to be more aware of what changes I can make in camera raw, for the most part I make changes in CS6 once the image has been opened

DPP Part 1 - Exercise 2 - Your own Workflow 2

 Part 1 - Exercise 2 - Your own Workflow 2

The aim of this exercise is to devise a workflow for a specific shooting assignment – for this exercise and unlike exercise 1 the assignment is unstructured and open ended:

Key elements of work flow are:

i)         Number of images is unpredictable, likely many

ii)       Lasts a sufficient amount of time that you would want to review the images “and partially edit during the shoot”

I found this last statement, in italics, particularly strange since I would never edit images in the camera, I would always work on the RAW file using my post processing software. However I am interpreting this statement in the course work to mean reviewing the images and deleting definite non keepers.

Pre-Shoot Work Flow

I've reviewed the workflow I used for exercise 1. I have planned an early evening landscape shoot and because it was sunny decided to also take my infrared camera. As there is no model involved I've removed the pre-shoot brief. For the main part its almost the same as Exercise 1. 

I think I am fairly happy with this pre-shoot workflow at this stage and in practice of following this twice. However I will as always remain flexible and adaptable as I learn more.

Reviewing this post shoot I was happy it works and its becoming good discipline that is starting to become 2^nd nature

Shoot Work Flow

I've adapted the Shoot workflow to reflect the change in shoot location and adapted it as it’s unpredictable and open ended. However shooting discipline still applies in terms of reviewing images mid shoot e.g. check histogram, and image composition and sharpness.

Reviewing this post shoot, though the shoot is less disciplined and open ended, shooting discipline in terms of image review / histogram review is still valid and essential. In fact what I did find was that there is more time to do this and I only have to think about the camera and myself; this was different to Exercise 1 where I had a model to consider and pose. This time allowed for deletion of definite non-keepers. I did complicate the shoot by using 2 camera’s, I've no doubt this could become good practice for future opportunities where this may be essential.

That said an open workflow for your shoot may mean that you don't know when you've finished e.g. there is no exit criteria / target to tell you that you have achieved what you set out to achieve.

I ended up in total from both cameras 270 images split 50-50 between jpeg and RAW, so that’s 135 images after in camera file deletions

Post Shoot Work Flow

I've detailed below my Post Shoot Work Flow:

I've removed the card from the camera and used the card reader to import to the computer via Bridge.

Some screen shots of the images in Bridge:

I've spent some time with Bridge as part of this exercise and am now using keywords to apply to my images  I've found this to be very powerful in how many key words I can I apply. I will read up on this as this should enable me to locate specific images from performing searches across 1000's of images

**This is a new element now to be added to my workflow** :

Looking through the images I've then deleted approximately half because:

i) I've thought the images not the quality I want

ii) Compostion issues that cant be rectified during post processing

iii) Obvious exposure issues

iv) IR images that reveal unappealing hot spots in the lens

I've applied a star rating to my images:

I wont process all the images but will process some of the better (in my opinion of course) images.

For the purpose of this exercise I will process 2 images continuing my workflow.

My first selected image to process I've opened the RAW file in Camera RAW and initially adjusted:

 - Exposure - the image was a bit under exposed

 - Contrast

 - Shadows

I've then opened the file properly in CS6 and saved the images a PSD file

I've then:

 - cropped the image, removing empty areas such as sky and grass from top and bottom of image

 - adjust levels by moving the left hand slider slightly right

 - sharpened the image using unsharp mask

 - File size amended by making the longest length 1000 pixels

Saved the image as a jpeg at a small enough size to upload to my blog:

My second image I've opened the RAW file in Camera RAW and:

 - adjusted the exposure to lighten the image slightly

I've then opened the image in CS6 and:

 - slightly adjusted the levels bringing the third slider further in to align to the right of the histogram and slightly lighten the image a bit more

 - sharpened the image using unsharp mask

 - cropped the image removing some of the sky from the top where it appeared a bit wasted and distracted from the image

 - Cloned out some bird droppings from the stone

- File size amended by making the longest length 1000 pixels

Saved the image as a jpeg at a small enough size to upload to my blog:

This image was taken a bit later than the one above and my intention was to create an almost candle type effect with the sun at the top of the stone

Exercise Learnings

a) Thinking through the workflow like this has now resulted in much thinking so much more about what I want to do at the shoot and be prepared. Whilst there should be the ability to take advantage of elements or change tack for whatever reasons may occur its important to start with a plan of what you want to achieve. This in turn helps ensure the right equipment has been taken

b) As part of the post processing I have this time used Bridge to greater effect tagging the images, deleting poor images and grading the images via the star system. This is something that I very much wanting to get into good habits and doing it religiously - this will be a change from what I used to do

c) I think there is nmore I need to learn about post processing and I think I need a better and more informed basic process. I will read up on this so that I can improve this aspect

d) I've never before thought about workflow in such a precise way but its just as important as the effort in taking the image.

e) I will print off my workflows and use these as reminder guides. I've no doubt I will adjust and add to this as I progress