Characteristics of the Canon EOS 600D (Rebel T3i) digital camera

Fig 1. Photo from Canon EOS 600D page

Sensor type: APS-C CMOS Pixels: 18 Mp, 3:2 Pixel pitch: 4.28 μm/pixel	3456 pixels 14.9 mm = 232 px/mm
5184 pixels 22.3 mm = 232 px/mm

Remote capture: Yes, with live view
Remote focus control: Yes
Lens compatible with eyepieces:  No
Raw mode: Yes
Filter mount: Yes

Computer control ('remote capture')

The EOS 600D / Rebel T3i can be controlled from a computer via USB, with live view (a view on the computer of what the camera sees). Canon's EOS Utility program can set many camera functions, trigger the shutter, and transfer files.

Photographing what human eyes can see through optical instruments

With most lenses typically used with this camera, the entrance pupil of this camera is much larger than a human eye, so it cannot take full-frame photos through optical instruments such as a microscope or binoculars. However, with no lens attached, real images produced by optical instruments and eyepieces can be projected directly onto the Rebel's large sensor, often eliminating the need for several pieces of glass and thus producing sharp images.

Other

The camera does not correct for lens distortion, and the kit lens has fairly significant barrel distortion at wide angle. However, RAW post-proccessing packages, such as Canon's and Adobe Lightroom, can do lens distortion correction for this lens.

When the 600D/T3i takes a photo, it lifts the mirror (if it isn't already up, eg., due to being in 'live view'), releases a mechanical shutter curtain, exposes the sensor, releases a second mechanical shutter curtain to hide the sensor, then drops the mirror to recock the shutters, then, if in live view mode, raises the mirror again. This means the camera is pretty noisy when taking a photo, and all the mechanical activity can cause vibration (eg., a concern when mounted on a microscope). Fortunately the worst of it (the mirror movements) can be arranged to occur after the exposure.

Here's a review of the lens (on a 700D, which has the same sensor). The lens is best at f/5.6 and with wide to medium zoom.

Focal length versus Angle of view

The camera was set at Distance from a perpendicular tape measure (measured from the 'sensor plane' indicator on the camera). Photos were taken at various focal lengths labelled on the lens, and then the angle of view was calculated. It's possible the angle of view is affected by the focus distance.

Sensor

The sensor has been analysed by TechInsights.com in this report.

Raw files produced by the camera are larger than final image produced, having a border on the left and top. To obtain the entire frame, including the borders, one can use Johann Briffa's scripts for running the Stanford PVRG JPEG software.