Shooting indoors needs proper external studio lighting equipment and techniques. How to capture the right light or achieve effect you want can be quite an issue in photo sessions.
Before we explore the secret of ISO, let’s figure out the definitions first.
The ISO refers to film sensitivity to light. ISO value is determined by its numbers: the lower the number, the lower the camera sensitivity to light. In the same way, higher number means it is more sensitive to light.
Each level you increase the ISO of your camera, the sensor’s sensitivity will be doubled (ISO 100 to 200, 400, 800, 1600 and so on), which means that you need half the amount of light hitting your sensor for the same exposure.
ISO can help you capture images in the environments lack of lights or with complicated lights, especially in studios. Higher ISO number does not mean progressively brighter image. By contrast, that means a bad exposure corresponding to higher sensitivities which can lead to reduced image quality. In other words, high ISO number for shooting in dark environments will show a lot of grain, also known as noise, which will undesirably obscures the desired information in the image.
Once knowing the definition of ISO, you may always hear that the lower the ISO number, the better the ISO, for that will lead to a cleaner looking. Well, that’s not the accurate understanding about ISO.
A lower the ISO number means there will be less grain or noise in the image. However, what noise or grain intends to achieve eventually is to presents more information of an image under the circumstance of lacking light. Noise consists of both luminance and color differences, it won’t remove detail. By contrast, the noise reduction can eat detail for the light is not enough. So ,it can not be simply regarded that lower is better, while ignore the situations which need high ISO.
For example, there is a inevitable dark environment or you just want to use high grain/noise as an artistic effect.
With the discussion above, we can be clear with that ISO settings shall be based on actual light requirements, and complement it with shutter speed and aperture. Actually, the most priority is always the use of light. So, guaranteeing the light you want and than adjust the exposure triangle.
Try to minimize noise and maximize image quality with enough light, which means that you can keep the ISO setting at a low number (100 or 200) in bright environment.
Even there is indeed lack of light and if you won’t use flash, you still can firstly adjust aperture or shutter speed but not the ISO.
Here are some examples:
- 100 or 200 best ISO for Indoor pictures with enough light;
- 400 ISO for cloudy days, or indoors for window light portraits;
- 800+ ISO for really low light situations, or some specialartistic effect created by noise you want.