The object of theses exercises was to investigate focus, and extend the camera firstly by using widest aperture (and therefore shortest depth of field) and changing point of focus; and secondly reversing this - change the aperture but retain a fixed point of focus.
Used camera and 25-105mm lens for both exercises setting camera to aperture priority.
Bitton railway station was chosen as likely to offer potential subjects for both exercises. I had much more difficulty with the first than the second. Spent 20 minutes experimenting with photographing the train but could not get sufficient differential of focus, then tried fire buckets, train lines and adverts before reverting to train again. It clicked then that need to get VERY acute angle on train. Took following images using f4.0 and allowing camera to adjust shutter speed.
Pleased with result - first image is sharp on handle and blurs to distance, second was sharp at about halfway (see the sharp reflection of the seat in the window) with blur in near ground.
Much easier to find subject for second exercise - a row of cycle hoops was just what was needed. Used same equipment and took following images focussing on the second hoop from the left. Used autofocus but changed to one point focus.
f22 shutter speed 1/10 - tripod essential. Good depth of field
f8.0 shutter speed 1/60. Reasonable depth of field but focus lost in distance and near hoop.
f4.0 shutter speed 1/125. Sharp only on second hoop.
Found this a useful exercise in 3 ways:
- Used manual focus possibly for first time to get the train images working;
- Was patient! Took time to get train images right but they work OK;
- Used AV - have done this before but need to get wise.
