Aperture and Depth of Field

Aperture Aperture is the size of the opening in the lens when a picture is taken. When you hit the shutter release button of your camera a hole opens up that allows your camera’s image sensor to catch the scene you’re wanting to capture. The aperture you set impacts the size of that hole. The larger the hole the more light that gets in – the smaller the hole the less light.

A Camera like a Bucket of Light Shutter: controls the amount of time the light comes into the camera Aperture: controls the amount of light by the size of the hole Photo sensitive surface (used to be film) now is a digital sensor. There are 2 types: CCD and CMOS (inside the bucket on the bottom)

A Camera like a Bucket of Light Small Aperture (f 16, f 22, f 32) – Small hole allows a small amount of light in the bucket Big Aperture (f 2, f 2.4, f 4) – Big hole allows a large amount of light in the bucket

A Camera like a Bucket of Light Small ISO (100,200) – big bucket, takes a lot of light to fill Big ISO (800,1600, 3200) – small bucket, takes a little light to fill

Aperture and F Stops Aperture size is expressed as an f-number (written as “f/” followed by a number), such as f/1.4, f/2, f/2.8, /f4, f/5.6, f/8, f/11, f/16, f/22, or f/32. Changing the f-number changes the size of the aperture, changing the amount of light that passes through the lens. The higher the f-number, the smaller the aperture and the less light that passes through the lens; the lower the f-number, the larger the aperture and the more light that passes through the lens.

Aperture and F Stops For example, changing the aperture from f/5.6 to f/8 halves the amount of light passing through the lens and halves the brightness of the image that falls on the image sensor. One f stop

Depth of Field Depth of Field the range of distance that appears acceptably sharp in a photograph 

Things that affect Depth of Field (DOF) Closer subjects to the camera cause narrower depth of field Zooming in on a subject (increasing focal length while maintaining the same position) massively narrows the depth of field Aperture has a very large impact on DOF. The smaller the aperture, the greater the DOF.

Depth of Field and Aperture f 22 = long DOF f 2.8 = short DOF

Photographing the Same Scene at Different Apertures

Photographing the Same Scene at Different Apertures

It has to do with the optics inside the camera Why is this happening? It has to do with the optics inside the camera

A ruler and increasing DOF Increasing Depth of Field

Using Depth of Field for different compositional effects Same Subject, different Depth of Field

Using Depth of Field for different compositional effects Don’t be afraid to throw your subject out of focus

Using Deep Depth of Field for compositional effect There are times when you want the whole image in focus

Using Short Depth of Field for compositional effect There are times when you want to focus on one part of the image

So experiment with different apertures on the same shot…