iphonegraphy

• Tags:: photography

Exposure

The amount of light we let hit the sensor. We need to nail it at the time of the photo or you lose some details. Under exposure means losing info in the dark areas, over exposure means losing info in the light areas. An histogram helps you with that.

In IPhones you usually have a generic “exposure” control, but there are three parameters:

• ISO: the sensitivity of the sensor to the light. The higher the ISO, the more sensitive: image will be lighter but will have more noise. So we should aim to use the lowest value possible without losing detail from darker areas.
• Shutter speed: usually as fast as possible (although it is measure in reverse: by the time you leave the shutter open) because we will usually want to freeze a moment in time, but we may play with slower speeds to add motion blur and have light trails, water trails… Measured in fractions of second. Note that it also affects the light we capture (faster speeds capture less light).
  • On iPhone you can only do manual motion blur in low light conditions: you cannot change the aperture to accept less light (see below). You can simulate it though with “Live” photos (long exposure toggle).
• Aperture: controls the depth of field. Greater apertures blur the backgrounds. Measured in fractions of the focal length of the lens. In an iPhone Pro the three lenses have a fixed focal length and depth of field adjustments are done computationally (but the iPhone has additional methods to capture depth, such as the multiple cameras and the LIDAR sensor). So we can change this after the fact if we are able to clearly separate whatever subject we have from the background (with more options if we use Halide).

White balance:

While our eyes compensate lighting conditions so that whites look “white”, cameras are not so great. Adjusting white balance is adjusting temperature and possible tints (e.g., from a greenish fluorescent).

When shooting (raw)

So your actual adjustment order is:

1. Pick lens (sets aperture).
2. ISO low.
3. Shutter speed for scene (if action → fast. Otherwise, as slow as you can: can’t shake it for the duration of the capture, so higher values if handheld vs. tripod).
4. Balance ISO ↔ Shutter until exposure is right.
5. Focus.
6. White balance.
7. Shoot. They say it’s better to underexpose a little since it is easier to recover detail from shadows than to do it from highlights.

When editing

Steps (for Darkroom):

1. Start with a preset closer to what I want.
2. White balance (Temperature) → Exposure (Brightness) → Shadows/Highlights → Contrast.
3. Fine-tune with curves if needed.
4. Adjust colors (HSL, vibrance).
5. Add sharpening and noise reduction.
6. Work with masks.