You have a number of file format options when making photographs with your digital camera. Each of us has an end use in mind when we photograph: web galleries and blogs, prints, or shares. The following recommendations are for the best image quality overall. Keep in mind that resizing or resampling is an easy matter these days, so why not get the best captured file and then alter it to your specific end use later? In any case, here are my recommendations to get the best image quality your camera can deliver.
Here's the back of a Pentax camera showing the menu for choosing "Image Capture Settings." This is where you choose the file format and compression. When this item is highlighted push the OK button (or in some camera toggle the 4-way controller to the right) and all the options are shown. In this illustrations JPEG "Large" is chosen with the lowest compression ratio.
If you shoot in
JPEG format:
- Choose the largest file size you can get. If you have a choice
of various pixel resolutions choose the largest. Cameras give you the
ability to choose among a number of JPEG file size images To get the best
results choose the largest size as this insures that you'll capture all
the information the sensor is able to record. 2
- Choose the lowest compression ratio. Compression is a way for
the system to gather more images on a given capacity memory card, but it
tosses away information when it writes to the card and replaces that
information with mathematical formulas, not "raw" image data.
- Don't "tweak" the image processor in the camera with
contrast or sharpness settings. These are fine for special effects in the
camera, but you can do better with the image information later in the
digital darkroom.
- Don't use digital zoom. This actually crops into the sensor
rather than getting optical information through the lens. Even if you use
the largest available resolution (Large) and lowest compression you'll
lose information.
Here's the back of a Sony alpha camera. Here the size of the image (highlighted in red) and the Image Quality selector are separated. The size here is a large JPEG. Selecting the Quality item will then allow you to choose Raw only, or Raw+JPEG.
If you have a
camera that allows you to choose between JPEG
and Raw format, do the following:
- Choose Raw. Raw files allow for the most processing freedom
and deliver the best quality image. It’s higher in bit depth (more
information) and is not compressed, thus is called “lossless.” The only
drawback to Raw is that you have to open and view and change the image
file in special software, usually bundled with the camera that has a Raw
mode option or a third-party raw processing software, such as Adobe Camera
Raw.
- If you have a choice of
pixel resolutions in Raw, choose
the highest pixel count. In most cases Raw automatically chooses the
highest resolution your camera can deliver, but some cameras now offer a “small
Raw” (s-Raw). This is offered to help speed workflow for those who do not
need very large files but still want higher bit depth and no compression.
For most of us this does not apply, especially when making our own prints.
In ye old days memory cards were
expensive and images per card were often limited, both by capacity and budget.
These days that’s almost a non-issue, so my best advice is: Shoot RAW+JPEG. That way you have a
small and portable JPEG and a file you can use for prints. The camera records
both simultaneously and the image will show up in both formats in your browser.
Although the image resolution or file size is key, that's just part of the equation. Of course, exposure and lens
sharpness and how the camera's internal image processor converts the data from
the sensor to digitized image information all have a very important role to
play as well.
