How do you calculate the exposure of an image?
In photography, this equation governs the fundamental relationship between the scene, the camera, and the captured image: Image brightness ∝ Scene illumination × Subject reflectivity × Lens aperture area × Shutter open time × ISO sensitivity .
How do you calculate equivalent exposures?
Calculating Equivalent Exposures
- increasing the aperture value darkens the image while decreasing it makes the image brighter.
- decreasing the ISO value darkens the image while increasing it makes the image brighter.
- increasing the shutter speed darkens the image while decreasing it makes the image brighter.
How do you calculate exposure for astrophotography?
The first exposure time you get is less accurate (500 rule) but useful when you don’t know the minimal star declination. Basically, to determine the optimal length of exposure, you take 500 and divide it by the effective focal length of the lens (Exposure time = 500/[crop-factor × focal length]).
What is the equivalent exposure to using ISO 100?
An exposed value of f/8.0 at 1/15 sec with an ISO of 100 is equivalent to f/2.8 at 1/125 sec with an ISO of 100. Changing to this equivalent exposure produces a shallow depth of field, causing the background to blur, drawing attention to the subject.
What’s an equivalent exposure?
Equivalent exposure is a term used to describe finding the right balance of a few factors (like ISO, aperture, and shutter speed) to create the right exposure for an image. When capturing a photo, this usually takes place by juggling things like aperture, the ISO, and shutter speed.
Is it better to over or underexpose?
Are you shooting raw or JPEG. If you are shooting JPEG, then the general rule is to underexpose because if you lose the highlights in a JPEG, these highlights are simply lost, unrecoverable. If you are shooting raw, the general rule is to overexpose the image to get more light (more exposure) into the shadows.