| Requirement/Feature | Status |
|---|---|
| Input for lighting condition | Finished |
| Input for setting to be recommended | Finished |
| Input for other 2 prefered settings | Finished |
| Check if output is too dark/bright | Finished |
| Logic uses 'Modified Sunny 16 Rule' | Finished |
| Output: Lighting Condition, Selected Settings, Recommended Settings | Finished |
| Automatic Mode: Asking for lighting and mode (portrait/sport) | Not-Doing |
| Semi-Automatic: Ask for one preferred setting, output other 2 | Not-Doing |
| Error-Checking | Finished |
| Summarise lighting condition, mode and settings | Not-Doing |
To use this program, you can either download the .py file and run it using Python (this was written using Python 3, and any deriverative should work with this [e.g. 3.7, 3.8]) or you can open the file and copy and paste whatever pieces of the code you need into an editor (such as Grok). If you find this code useful in any way, please feel free to star the repo and share with friends, a follow would also be appreciated.
The ISO is the sensor at the camera body. The sensitivity is directly proportional to the amount of light in an image (i.e. Doubling the ISO doubles the image brightness)
- The higher the ISO The brighter the image (is also directly proportional)
- The higher the ISO The noisier the image (as the sensor is more sensitive to light, not more light entering)
The Shutter speed is the amount of time that the ISO can have light for. Shutter Speed is directly proportional to the amount of light in an image (i.e. Doubling the Shutter Speed doubles the image brightness)
- The higher the Shutter Speed The brighter the image (is also directly proportional)
- The higher the Shutter Speed More motion blur is visible (as the shutter is open for longer, it can take photos while the subject has moved, making it blurred)
Controls the amount of light that the sensor recieves. (Note that the larger the f-stop number, the smaller the aperature). Aperature is inversely proportional to the amount of light in an image (i.e. Decreasing the f-stop by a factor of √2≈1.4 will double the brightness in the image.)
- The higher the Aperature the dimmer the image (is inversely proportional)
- The lower the Aperature
This is a rule that states on a sunny day, if you set the aperature to f/16, then you should set the shutter speed to the reciprocal of the ISO, for example (ISO: 200, Shutter-Speed 1/250s (as there is no 1/200s), Aperature: f/16)
This is a rule that can be used in other different lighting conditions, with the use of specific lighting conditions. These are:
| Lighting Condition | Aperature |
|---|---|
| Snow/Sand | f/22 |
| Sun | f/16 |
| Lightly Cloudy | f/11 |
| Cloudy | f/8 |
| Overcast | f/5.6 |
| Sunset/Shade | f/4 |
| Dusk | f/2.8 |
From these aperatures, you can then set the shutter speed as a reciprocal of the ISO (e.g. Cloudy Day = ISO: 800, Shutter Speed: 1/1000s (as there is no 1/800s, nearest setting), Aperature: f/8.0)
This is done by using an equation, and example will be displayed in the table below: (For a cloudy day)
| ISO | Shutter Speed | Aperature | Result |
|---|---|---|---|
| 800 | 1/1000s | f/8.0 | 1 (Notional Baseline) |
| 100 (÷8) | 1/2000s (÷2) | f/2.0 (x 42) | 1 ÷ 8 ÷ 2 x 16 = 1 |
| 400 (÷2) | 1/500s (x2) | f/8.0 (x1) | 1 ÷ 2 x 2 x 1 = 1 |
| 1600 (x2) | 1/500s (x2) | f/16 (÷22) | 1 x 2 x 2 ÷ 4 = 1 |
As you may have noticed, each seemingly increment doubles or halves the brightness (approximately), and this can be known as a 'stop'. I will have a graph below with all of the possible stops: (Note: This graph goes from least bright to most bright, from bottom to top)
| ISO | Shutter Speed | Aperature |
|---|---|---|
| 6400 | 1/30s | f/2.0 |
| 3200 | 1/60s | f/2.8 |
| 1600 | 1/125s | f/4.0 |
| 800 | 1/250s | f/5.6 |
| 400 | 1/500s | f/8.0 |
| 200 | 1/1000s | f/11 |
| 100 | 1/2000s | f/16 |
| 50 | 1/4000s | f/22 |
For you to have the same amount of brightness, all movements from the baseline have to equal out (e.g. ISO decreasing by 3 stops, Shutter Speed decreasing by 1 stop and Aperature increasing by 4 stops)
- Sports Shot (Faster Shutter Speed required)
- Example: Decrease Shutter Speed by 2 stops (from 1/1000s to 1/4000s), increase ISO by 1 stop (from ISO 800 to ISO 1600) and increase aperature by 1 stop (f/8.0 to f/5.6)
- Portrait (Larger Aperature is required)
- Example: Increase the Aperture by 4 stops (from f/8.0 to f/2.0), Decrease the ISO by 4 stops (from ISO 800 to ISO 50) and keep the Shutter Speed (1/1000s)
| Reference No. | Lighting Condition | ISO | Shutter Speed | Aperture |
|---|---|---|---|---|
| 8 | Default | 6400 | 1/30s | f/2.0 |
| 7 | Snow/Sand | 3200 | 1/60s | f/2.8 |
| 6 | Sunny | 1600 | 1/125s | f/4.0 |
| 5 | Lightly Cloudy | 800 | 1/250s | f/5.6 |
| 4 | Cloudy | 400 | 1/500s | f/8.0 |
| 3 | Overcast | 200 | 1/1000s | f/11 |
| 2 | Sunset/Shade | 100 | 1/2000s | f/16 |
| 1 | Dusk | 50 | 1/4000s | f/22 |