5th course: Circle of confusion, sharpness, resolution, contrast, composition rules & setting up your camera
circle of confusion in photography
To understand the circle of confusion you must remember that light reflected off the subject in all directions, your camera will gather all the light rays from each point on the subject which are reflected toward the camera & fall within the circle created by the opening of the diaphragm.
You may visualize this as a cone of light which has its apex at the point of reflection on the subject & it’s circular base in the diaphragm opening, a circle of confusion also referred to as (blur circle, disk of confusion & circle of indistinctness), refers to the effect of non-converging, unfocused light rays that have entered the lens, when light waves don’t converge after passing through a lens, they produce a larger optical spot, instead coming together at a single point.
Being able to calculate the circle of confusion is important because it allows a photographer to interpret the depth of field necessary to render a focused image in the photograph.
If the photographer is at the proper distance from his subject, he can minimize possible light & chromatic aberrations, this better ensures that the different wavelengths of light entering the camera lens will form a concentrated, focused image on the film.
In simple terms, the circle of confusion is an estimated calculation of the depth of field necessary to produce a clean image.
Circle of confusion = COC
Out of focus = Large circle of confusion
In Focus = very small or no circle of confusion
Is the most important photographic image quality factor because it determines the amount of detail an imaging system can reproduce.
Sharpness describes the clarity of detail in a photo & can be a valuable creative tool for emphasizing texture, proper photographic & post-processing techniques can go a long way towards improving sharpness, although sharpness is limited by your camera equipment, image magnification & viewing distance, two fundamental factors contribute to the perceived sharpness of an image: resolution.
what does resolution mean?
The traditional analog world was easy to understand, negatives & print were continuous tones and one simply made an enlargement from the negative & transparency to the size needed. Today in the digital environment, many newcomers get tripped by the concepts of input & output resolution, & terribly confused as to what settings to use, to understand these issues clearly one needs to start with an acceptance of certain physical limitations of the human eye, our vision is incapable of discriminating detail below a certain level, this varies from individual to individual & even the same individual in different ways.
When an image is composed of dots smaller than this they appear to the eye as a continuous tone, this has been relied upon by the printing trade for a couple of hundred years, every photograph & every image that you see in every book, magazine, calendar & art reproduction is comprised of dots of ink, at resolution typically ranging from 70 to 300+ dots per inch.
Best quality lenses, lowest ISO & the quality of your sensor will determine the recorded resolution.
what does contrast mean?
Is the range of difference between different tones in a photograph, in black & white photography, contrast describes the difference between the darkest & the lightest tones, but also defines the grayscale, in color photography, contrast applies to how sharply colors stand out from one another.
Composition & design rules:
Rule of thirds explanation
Rule of thirds:
Imagine that your image is divided into nine equal segments by two vertical & two horizontal lines, try to position the most important elements in your scene along these lines.
Placing your main subject off-center as with the rule of thirds, creates a more interesting photo, but it can leave a void in the scene which can make it feel empty, you should balance the weight of your subject by including another object of lesser importance to fill the space.
Setting up your camera:
- Raw or jpg
- Select your mode ( Manual, P, AV, Etc ..)
- ISO (in relation to time & light)
- White balance (if you want)
- Focus point – centered, all points or off to a side
- Auto or manual focus
- Single or continuous shooting
- Fill Flash
- Take test image & review (always remember the exposure triangle)
Now you have finished the full course, you did a good job 😉 start practicing & if you have any questions just post below & I will be glad to answer you.