Focus with a set aperture:
A scene was chosen which had depth. In this case I chose a line of champagne bottles with one odd one out! Three photos were taken from the same point each one focussed on a bottle at a different distance. The camera was set at it’s lowest f-stop number. The three images were then compared and the preferred photo noted.
‘Near’ Focus (Nikon D90 with 18-55mm, ISO 200, 1/13sec at f5.6)
‘Middle’ Focus (Nikon D90 with 18-55mm, ISO 200, 1/13sec at f5.6)
‘Far’ Focus (Nikon D90 with 18-55mm, ISO 200, 1/13sec at f5.6)
I spent a bit of time selecting the right scene for this exercise and in the end selected some champagne bottles lined up. The near and middle photos I am happy with as a clear distinction is seen between where the eye is drawn. However with the far photo I suspect I am limited by the lack of distance between the near and far bottles and also the f-stop of 5.6 which in this case was not low enough to give distinctive depth of field. My preference is for the middle image.
Focus with different apertures:
A scene was selected showing a row of dry stone wall from an angle. Each photo was framed identically focussed on a mid point on the wall. The first of the three photos was taken at f5.3, the second at f13.0 and the third at f36.0.
‘Wide Aperture’ Nikon D90 at 90mm, ISO 200, 1/500sec at f5.3
‘Mid Aperture’ Nikon D90 at 90mm, ISO 200, 1/50sec at f13
‘Narrow Aperture’ Nikon D90 at 90mm, ISO 200, 1/8sec at f36
As you can seen a wide aperture setting creates a smaller depth of field. To obtain a sharp image from the front to the back of the frame then a small aperture should be used from about f/11 upwards. In the above images a clear difference exists between the wide and narrow apertures but less so with the mid aperture.