This page is used to evaluate different optical lens and camera settings

Sensor size	Size of the camera sensor, is is possible to select many standard sizes, some specific cameras and a custom setting
Width in mm/Height in mm	Custom specification of sensor size
Focal length in mm (native)	The actual focal length, on SLR it is the value specied on the lens
Focal length in mm (35mm)	What focal length to use with 36×24 mm sensor to get the same angle of view
Aperture	Actual aperture selected on the lens or camera
Distance in meter	Distance from camera to motive
Circle of confusion	Select picture sharpness
Sensor resolution in mega pixels	An estimate of pixel size is done based on this value

The curve shows depth of field. The blue line is the near limit and the yellow line is the far limit.
Click on curve to get readouts.

Sensor	Sensor width, sensor height and sensor diagonal are shown
Aspect ration	Actual aspect ration for selected sensor is calculated
Crop factor	Actual crop factor, compared to 35 mm, is calculated
Native focal length	The actual focal length of the lens
35 mm focal length	What focal length to use with 36×24 mm sensor to get the same angle of view
Angle of view	Angle of view for diagonal, width and heigth is calculated
Field of view	Field of view for diagonal, width and heigth is calculated for specified distance
Depth of field	Distance to start and end of focus range is calculated
Total depth of field	How large the "in focus" range is
Hyperfocal distance	When distance on lens is correctly adjusted, it is possible to get everything beyond this distance in focus
Circle of confusion	The actual size of "Circle of confusion", this is calculated both on sensor and on a small print
Diffraction limit	Unsharpens due to aperture
Sensor pixel size	Assuming the sensor has square pixels, a pixel size and a (estimated) resolution is shown here
Sensor MP	Megapixels for a selected camera
MP at 35 mm	What would the resolution be, if a 35 mm sensor was made with the same pixel density
Focus distance	Actual focus distance, selected on curve
Focus before object	How far before the selected focus distance is in focus
Focus after object	How far after the selected focus distance is in focus

Because the length of lenses does not match the focal length, the distances will not be correct. This is only relevant at short distances
The "Circle of confusion" is based on a 30 um circle at 35 mm film (Standard quality). Some DOF calculators uses a 25 um circle
Circle of confusion are calculated as a fraction of the picture height to keep constant values when changing aspect ration
When making big prints that must be viewed at very short distances, a smaller CoC must be used
Depth of field is always based on acceptable sharpness (Circle of confusion setting), a lens has only fully focus at one distance
Diffraction limit is a physical limitation and can not be improved

MiscEl: Photo lens