The minimum focus distance is the closest distance from the focal plane, the sensor, to the subject at which the lens is able achieve focus. If you get closer than the minimum focus distance the lens will NOT be able to focus on the subject. This typically happens when you try to take close up pictures, for example of flowers, insects or jewelry.

The minimum focus distance is lens dependent and the value can be found, usually specified in feet and meters, via the manufacturer specifications for the lens of interest. For example the Canon 100mm F/2.8 IS macro lens has a minimum focus distance of 0.99ft or 0.3m.

The minimum focus distance is measured from the focal plane, the sensor (NOT the front of the lens), to the subject. The sensor position in your camera is typically marked on the outside of the camera body with a line through a circle symbol, which is the starting point of the measurement.

Some lenses have switches to limit the minimum focus distance so the the camera cannot focus on objects close to the camera. For example, if you wanted to take a portrait of someone through tall grass. In this case you would not want the camera to be able to focus on the close objects, the grass, just on the subject you are trying to take the portrait of.

In our next lesson we will discuss “plane of focus” which is related to a previously discussed topic “Depth of Field“.

From our last lesson about “camera image resolution” that the size of the image is based on the camera sensor type and specifications, and is where the light is captured and converted into a digital image.

Image quality set to “RAW”

Not all cameras have the feature to capture images in “RAW” format, check your camera image quality settings to see if its an available option.

When the captured “image” is read directly from the sensor and then stored on the camera’s memory card without any conversion or processing, the saved “RAW” file is commonly referred to as a read-only digital negative. The “RAW” format is a proprietary format for each camera manufacturer and camera model.

From the diagram below we see that the camera settings influence the Jpeg preview that is processed from the RAW file which then gets added to the RAW file before being stored on the memory card.

Advantages with image quality set to “RAW“:
■ Maximum amount of digital information captured in the image (higher dynamic range)
■ White balance colour values in “Kelvin”
■ More than 8 bits of colour
■ Uncompressed (lossless)
■ Read-only Digital Negative

Disadvantages with image quality set to “RAW“:
■ Every image requires post-processing
■ Large files, require more storage space
■ Images take longer to upload from the memory card to the computer
■ Limits the number of images captured in burst mode
■ Requires conversion/processing before being printed

There are many who say you must shoot in “RAW”. While choosing to shoot in “RAW” does give you the most amount of information, it is not always necessary or advantageous to use the “RAW” image quality setting, because it depends on what you are shooting. For example, if you were taking images at a sporting event and the images need to be published immediately then “RAW” is probably not the best choice. However, if your are taking landscapes then “RAW” would be the best choice.

Image quality set to “Jpeg”

The “Jpeg” quality setting is typically the standard default setting for your camera. It is important to understand that your camera settings apply post-processing to your image that is stored on the memory card.

From the diagram below we see that the camera settings and the camera image processor generate the Jpeg image from the sensor RAW information. The result of the camera processing is stored as a compressed “Jpeg” image on the memory card.

Advantages with image quality set to “Jpeg”:
■ Standard image file format
■ Smaller files, less storage space
■ Share directly to social media
■ Directly to print
■ Camera settings applied directly to image (post-processing)

Disadvantages with image quality set to “Jpeg“:
■ Limited dynamic range
■ Camera settings applied directly to image
■ Colour temperature applied directly to image
■ Compressed (lossy)
■ 8 bits of colour

My humble opinion it takes great skill to successfully shoot with the “Jpeg” image quality setting. From knowing how the camera settings directly affect the captured image to getting an exposure that looks good right out of camera is challenging even for the most skilled photographer. For example, some of the best photographers in the world shoot with “Jpeg” image quality at the Olympics as they have their cameras directly connected to the wire service that gets an image out to the media, on average, within 90 – 120 seconds of the image being taken.

You as the photographer need to decide how far you want to go based on what genre you are shooting, how your image will be used, who the image is for, and how much time and resources you want to spend on each image. Choose the right image quality setting that meets your needs.

In our next lesson we will discuss what minimum focus distance means.