Basics - Manual Controls (exposure, ISO, shutter speed)
This article goes over some of the most important tools to master: exposure and manual controls. Be sure to read this thoroughly!
EV (exposure)
The exposure tool is the middle control in the manual controls bar. This one’s simple--it brightens your image if you slide to the positive values on the right and darkens as you move to the left. 
To understand the next controls, you’ll need a quick rundown on how images are produced by a traditional camera. Exposure is a balance between three different settings on your camera -- shutter speed, ISO, and aperture -- which dictate how much light is let in to expose your image.
Now, you'll notice both SS (shutter speed) and ISO in the manual controls bar, but Aperture is missing. This is because the aperture value on your phone is fixed and cannot be adjusted. That leaves us with the ability to adjust the ISO and Shutter Speed to manually control an exposure. They key to these two settings is finding the right balance between the two in order to achieve the image result desired.
ISO
ISO is how sensitive the camera sensor (used to be film) is to light. The higher the number, the less light is needed to expose a photo. There is a trade-off, though. As you increase the ISO, your photos gain noise. Generally you'll want to keep the ISO as low as possible, as this allows for the most dynamic range.
Shutter Speed
Shutter speed controls how long the sensor is being exposed to light. With slower shutter speeds, the scene is generally brighter and moving subjects will show motion blur. With faster shutter speeds, the scene is darker and moving subjects are sharper. The values are listed in fractions of a second, or even as slow as 1 second on some phones.
Why can't I set a manual value on the Shutter Speed, ISO, and Exposure controls at the same time?
When you set Shutter Speed and/or ISO, Exposure becomes unlocked. If you set Exposure, then Shutter Speed and ISO become unlocked. What gives?
With the way the phone's camera system works, setting Exposure is essentially automatically setting ISO and Shutter Speed values under the hood, so manually setting ISO and Shutter Speed is just overriding what the Exposure control sets.
You can either have...
- both ISO + Shutter Speed values locked but Exposure unlocked,
- Exposure value locked and both ISO + Shutter Speed unlocked, or
- all controls unlocked. (To unlock all controls simply double-tap the viewfinder).
How do I reset values set with the adjustment controls?
To reset all of the values, simply double-tap on the viewfinder. To reset a single adjustment control value, double-tap on the control’s button.
What More Tips?
We wrote some articles on how to get more out of the app.