A Hyperfocal/DoF Utility
Bokeh is a simple iphone application for photographers. It is designed to help you to control the depth of field in your pictures more effectively. Bokeh uses two modes: Hyperfocal mode and DoF mode:
In this mode, Bokeh calculates the hyperfocal distance for a given focal length and aperture combination that you can input with the two sliders on the screen.
The hyperfocal distance, is the focussing distance which you must set on you camera's lens in order to attain the maximum depth of field. The nearest distance at which objects will apear sharp, or in focus will be displayed in the lower part of the screen and it will reach to infinity.
Hyperfocal distance focussing is extreamly useful in landscape
photography. Remember that you need to set the focussing distance to the
hyperfocal distance and not to the starting distance. Use the
real (physical) focal length of your lens and not the effective focal length
attained from multiplying the camera's crop-factor with the lens' physical focal
length. The focal physical length is usually printed on the lens.
In this mode, you can calculate the exact depth of field for a given focal
length/aperture combination at a specific focussing distance. This especially
useful for portrait, macro and close-up photography. Focal length and aperture
slider work the same way as in hyperfocal mode. Use the distance slider to set
the focussing distance and use the unit selector to set the measurment units used
for setting the distance.
In a photographic image, sharpness related to focussing is gradually changing through the entire depth of a scene. DoF refers to an area of acceptable sharpness that will be percived as "in focus" when viewing the photograph. This perception however is dependant upon the conditions under which the photograph is viewed. Printing/screen resoultion, size and viewing distance have a large influence on what is percieved as "in focus". Bokeh calculates the values according to standard print sizes viewed at normal viewing distance and these results are equally applicable to images viewed on a computer screen at a reasonable resultion. Future versions may allow adjusting the calculations for different viewing conditions.