Exercise 3. – Focus at different apertures

The same scene, good “old” tomatoes…

These photos were taken at the same time as the previous exercise using the same lens and equipment, this time I’ve focused using the middle point and I’ve set the aperture to the widest, the middle and the smallest setting. Changing the aperture is one way to control depth of field. Depth of field or DOF is referring to the sharp area on a photo, in front of and behind the focus point.

30 mm, f/1.4, 1/60, ISO 100

30 mm, f/1.4, 1/60, ISO 100

30 mm, f/8.0, 0.5 sec, ISO 100

30 mm, f/8.0, 0.5 sec, ISO 100


30 mm, f/16, 2.0 sec, ISO 100

30 mm, f/16, 2.0 sec, ISO 100

The wide aperture of f/1.4 creates very shallow depth of field, only 4 tomatoes in focus and standing apart from the others but still not as sharp as on the other pictures. The aperture of f/8.0 gives a pleasing image, the middle part is definitely sharper, noticeably larger depth of field slowly fading away towards the edges of the picture giving a smooth, natural effect; the last one with f/16 results the largest depth of field, it’s sharp and shows every detail.

In terms of sharpness I prefer the second image, however I could have done it with a larger aperture to achieve better sharpness, 2.5 to 3 stops down from the lens’s maximum aperture also known as the lens’ “sweet spot”. Using my 30 mm f/1.4 lens this value is somewhere between f/2.8 and f/4 which would also create a shallower depth of field.

In terms of focus I could have done better choosing a bit wider aperture than f/16 knowing that is my lens’ minimum aperture, following the same theory with the maximum aperture, avoid using the lens on its limits the achieve better results.

I also noticed I haven’t paid to much attention to shutter speed – as I shot this in aperture priority – It stopped down to 2 seconds in the end, which would have caused problems if I would have shot without tripod. Nevertheless I should have adjusted the ISO accordingly to reduce the risk of blurry images.

  1. Good blog you’ve got here.. It’s hard to find excellent writing like yours these days.
    I really appreciate individuals like you! Take care!!

    • Krisztina said:

      Wow thank you, that’s very kind of you. I was hoping my writing would be acceptable as English is not my first language.

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