Histogram

This exercise is to increase our familiarity with histograms.

The histogram is a graph of visual brightness running from darks to lights (right to left). The number of pixels per  level of brightness run from bottom to top.

More useful information about histograms can be found here at the Luminous Landscape web site.

For this exercise I have taken nine photographs in groups of three. Each group represents a different picture scenario with one image exposed correctly and then one image over by 1 stop and one image under by 1 stop. We will look at each group of histograms and see what happens.

The first three images are of a fairly flat/low dynamic range. We can expect to see the pixels bunched together around the tone of the photograph.

F8 @ 1/100 ISO100 50MM

As expected the pixels are grouped closely together as there is not a great deal of contrast. This image is correctly exposed using evaluative metering- it was a bit of a dull day! There is no highlight or shadow clipping which shows up as bright red areas for highlight and bright blue areas for shadow in the Canon RAW processor.

F8 @ 1/200 ISO100 50MM

The next shot is 1 stop under exposed. Clearly visible on the histogram is that the tonal range has shifted to the left. Still no highlight or shadow clipping.

F8 @ 1/50 ISO100 50MM

The last shot in the first group is 1 stop over exposed. The tonal range has shifted to the right - to the brighter side of the histogram. Highlight or shadow clipping are still not evident. I must say I prefer the exposure on this shot even though it's one stop over by the camera's reckoning.

The second set of three images covers a broader range of contrast.

F8 @ 1/50 ISO100 50MM

Here the histogram clearly shows a larger degree of contrast. The histogram is wider and in fact covers almost 3/4 of the cameras dynamic range. The large peak at the right represents the large number of brighter pixels.

F8 @ 1/100 ISO100 50MM

The same image at one stop over. Evaluative metering was used for all of these shots too. Again the graph has moved to the left to show the shift to darker tones. Not enough for any shadow clipping though.

F8 @ 1/25 ISO100 50MM

Finally, 1 stop over. Highlight clipping has started to occur in the brightest part of the sky as can be seen by the bright red areas in the top right of the image. Looking at the histogram we can see the pixels are starting to extend out of the right hand side of the graph area.

Now for the last image. Don't laugh but this untidy mess is my desk. The first series of shots I took for the high contrast section was carefully staged. After cleaning the windowsill I shot the row of cactus pots we have. The contrast however seemed to get a bit flattened by the light coming through the window and the histogram wasn't much wider than the one for the shots with the boat. When I was sitting at my desk looking at the shots I noticed that the immediate surroundings had a good range of tones so I shot that instead.

F2.2 @ 1/20 ISO200 50MM

In the first photograph which is correctly exposed, I have already had to make some decisions about exposure. For a good exposure I have allowed a very small amount of  the highlights to clip. This can be seen by the bright red areas to the left of the photograph. Examining the histogram will show the tiniest part of the graph extending beyond the right hand edge of the graph range.

F2.2 @ 1/10 ISO200 50MM

The one stop over-exposed version of this photo shows large areas of blown out highlights. We have lost a large part of the graph which has been clipped. These pixels no longer exist in our image.

F2.2 @ 1/40 ISO200 50MM

And finally the one stop under-exposed version. The bright blue areas show where shadow clipping has occurred, namely on the side of the pencil pot and on the right of the image. This is nowhere near as much as the highlight clipping. Note that even though we are clipping the shadows,some of the highlights are also still being clipped.

In this final image we can clearly see that we have exceeded the camera's dynamic range - we are losing both shadow and highlight detail and should we wish to print this image, we would have to make a decision about which pixels to sacrifice!

The Agfa Silette 1 Exposed

I have put my first role of film through the Agfa Silette 1. The film was Neopan 100 ACROS and I had it professionally developed by Fuji print. The exciting thing was the printing though. My friend has a dark room and gave me a tutorial on printing.

I had a pleasant evening picking through my contact prints and printing up some of the images on 5 x 7. The images themselves weren't really anything to shout about , they where really taken to see if the camera worked and more importantly, to see if I could work with the camera!

I was quite happy with the way the camera performed though and could well see myself exposing a few more rolls of film to see if I can get to grips with it. Now I have found a manual on-line, I can start working with the depth of field scales too as there is no focussing through the view finder.

The evening has also encouraged me to get a couple of rolls of 120 to put through my Yashica 124G TLR.

Your own workflow 2 - Continued

The visit to Selsey Bill went ahead and I shot 160 images. I did delete a couple throughout the day but only when I found them to be really bad. This was because I had enough memory card space to carry on shooting and I find it easier to assess the shots on the computer monitor rather than the small display on the back of the camera.

I also spent time checking the histogram on location as I have rolled this exercise partially into the histogram exercise. Below is an image of the Canon RAW converter and image viewer with shots from the day.

Images in the Canon RAW converter (click for larger image)

I ended up with a number of shots that range from the record shots to artistic blurs and slow shutter speed work, which I am very interested in at the moment.

I created the receiving folder structure as planned in the flow chart and carried out a backup of the drive as soon as I had all the RAW files copied from the camera card.

At the moment I am still editing the images so I will come back to report on that aspect of the workflow when I have completed this. I edit most of my images down to display on Flickr but keep the Photoshop files in full size as I occasionally print these out for entry into the camera club competitions or exhibition.

Your own workflow 2

For one of my TAOP projects I spent a little time in Selsey Bill, a sea-side town on the South coast of the UK. I have another visit planned with a friend as there was a good variety of stuff to shoot and it will be interesting to visit at a different time of year. This day out will be the ideal subject for exercise 2.

The planning for this workflow starts at the equipment checking stage. Importance is placed on battery life and memory card capacity to sustain a day's worth of shooting - I am anticipating a large number of shots. It may be necessary to delete some of the shots during the day.

With this shoot the majority of the work will start when back at home. There will be many images to check over and maybe edit.

Below is my flow chart for this shoot.

(click for larger image)

The trip is planned in a weeks time after which I evaluate how well the workflow functioned.

Your own workflow 1

In this exercise we are tasked with creating & documenting our own workflow. This workflow will later be put to use and tested in a couple of projects.

It has become more important to have a good workflow in place. A digital camera is capable of producing a large number of images very inexpensively. In this digital age we also have complete control over  the editing & processing of image and the way we make it available for viewing, i.e. the internet, digital slide show or print. We also have to consider the fragility of a digital file over a printed photograph. Our workflow has to cater for the storage and security of the digital image.

Although the editing, processing and storage part of the workflow may be the same or very similar for any type of shoot, the first part of the workflow which deals with the preparation of equipment may vary.

This first workflow is for a small, time limited project such as a portrait shoot. I have using been a workflow that has slowly been forming without any deliberate planning so this is an ideal time to maybe firm this up and get it down on virtual paper.

Using the portrait session as the objective, the workflow actually starts even before charging the batteries. First a location is needed. I keep a list of possible locations and now also take a snapshot with my phone or compact when I come across a new one. This location scouting is a continuous process.

In this workflow the second thing I would need is a model or subject. This could be from among friends, family or from a modelling agency. As the shoot is going to be limited in time I will try to make a mental note or a printed list of poses I wish the subject to try out. 

Next comes preparation of the equipment which is noted on the chart. This completes the first part of the workflow. Everything now stops until the arranged time of the shoot.

(click for larger image)

At the shoot itself I must concentrate on the subjects poses and lighting to make sure I get the shots I need. All I can do here is check the camera screen (histogram) to make sure things look ok.

Back at home the last stage of the workflow cycle is the selection, storing and processing of the images. I use Canon Digital Photo Professional (DPP) as my RAW processor (I always shoot in RAW). DPP is used to transfer the images from the memory card to a newly created folder on the PC. I arrange my RAW images in a folder structure which is split into years followed by months or events, a month if the images are just random images or an event if the images all hail from the same occasion.

The RAW folder structure (click for larger view)

I usually perform the RAW adjustments in DPP and then transfer the image directly to Photoshop for any special effects editing and final output processing for print or web. The Photoshop files are also saved into a similar folder structure as the Raw files but I name the Photoshop files with a sensible name rather than the image number.

This outlined workflow will now be put to the test to carry out one of the upcoming exercises in the course.

Digital Photographic Practice - 1st post!

I have just completed my first OCA module ‘The art of photography’ which will be submitted in January for the 15th of March for assessment.

Whilst working on my Blog for the first module I made some firm decisions about what I wanted to do in my next Blog. For example, I found that a lot of my images were a bit ‘utilitarian’ and had started to drift away from ‘art’ in order to complete the exercises. In some cases there was no alternative to this but in my second module I would like to try and redress this and make the most creative shot wherever possible.

Another area where I wish to make a change is to print out the images for assignments so that I can supply them to the moderators as prints at the end of this module. I am also considering keeping a paper version of the Blog but haven’t come up with the best way of doing this yet. Maybe I will print out the posts and keep them in a scrap book? This is for the sole purpose of having a record of all the work to look back on in years to come and should anything happen to the internet version.

My books arrived last week and I been in contact with my new tutor, so now all that’s left is to get started!

I will be working with my Canon 5D MKII again but have added a compact camera with manual controls, the Canon S95. I bought this to have a small camera that I could carry around all the time. It should also come in handy for street & candid photography due to it’s small size.

Just for fun I have also bought a little old 35mm camera, an Agfa Silette 1.This is purely manual with no exposure meter. I have it loaded with a black & white film to see what I can do with it. This sweet little camera came from a car boot sale for £2.

Agfa Silette 1