It is always a delight to shoot photos when the available light is ample and you do not need any external light source on your subject. But there might be situations when the lighting condition is dim and you feel that the light is not adequate to capture photos without introducing external light source such as a flash.
You can always use a flash to throw light on your subject when the light conditions are dim, but that is not the only way out. Before you resort to using a flash, try and rethink about how you can play with the exposure setting in your camera to capture correctly exposed photos in such a situation.
1. Use Wide Aperture (smaller f/ stop)
The first thing you should be adjusting in order to capture well-exposed photos in low light conditions is the aperture value.
The wider the aperture opening, more the light would enter the camera through the lens. By selecting a smaller f/ value such as f/1.4 or f/1.8, you can let in more light and capture a well-exposed photo in low light condition.
By using a smaller f/ value you can also shoot at a faster shutter speed, which ensures that the shake is not captured in the photo because of the hand shake while shooting. But remember, using a smaller f/ value also results in shallow depth of field (more blur effect) so you will have to frame your shots accordingly.
2. Adjust ISO Sensitivity
The lower the ISO number, the less sensitive the image sensor is to light. Thus, more light is required by the image sensor in order to properly expose the photo. On the other hand, the higher ISO number increases the sensitivity of the image sensor, therefore less light is required to properly expose the photo.
As you increase the ISO number and make the sensor more sensitive to the light, you can easily click a well-exposed photo in low light conditions. If you double the ISO value (keeping the shutter speed the same), the sensitivity of the sensor increases two times and the exposure also increases by two times. So if you increase the ISO from 100 to 200, you can double the exposure of the photo.
For example, if you are shooting in low light conditions using the 50mm f/1.8 lens at f/1.8 and you are struggling to get the required shutter speed at ISO 100, you can increase the ISO value. Suppose at f/1.8 and ISO 100 your camera is suggesting a shutter speed of 1/10 sec, you can increase the ISO from 100 to 800 ( an increase of 3 stops) in order to use the shutter speed of 1/80 sec (an increase of 3 stops).
3. Shoot RAW
Shooting in RAW lets you retain all the details of the image which can be used during the post processing stage. Using the RAW file you can change the exposure as per your wish, as well as the white balance. You can also edit the same RAW file multiple times, without losing any details or affecting the image quality.
Read: RAW vs JPEG
One of the benefits of shooting in RAW format is that even if you click an under-exposed photo, you can always adjust the exposure during the post-processing stage. If you are struggling to get a well-exposed photo at an event, simply shoot in RAW format and you can pull back the details later. But remember, the RAW file captured by your camera can only retain details to a certain limit.
4. Choose Shutter Speed Carefully
One thing you need to make sure is that you choose a shutter speed that meets your requirement. What I mean to say here is that if you are shooting a wedding/event in low-light conditions, you must use a shutter speed which does not result in a shaky photo. A standard minimum shutter speed should be 1/60 sec or at least equal to the focal length of your lens to avoid hand shake being captured in your photo.