Depth of field

An appropriate operating the focus and defocus of each individual plans allows to draw the viewer’s attention on the specified items on the image.
The bokeh effect is in many areas of photography, for instance in a portrait, very desirable. Whereas it is not expected to be used for the product images, which have to be completely sharp and full of details.  The main key to obtain clear photos is a deliberate usage of all parameters affecting the depth of field.

Distance
The longer is the distance from shooting object, the greater is the depth of field.

Diaphragm
The smaller is opening of the diaphragm; the better is the depth of field.

camera-aperture
Focal length
The shorter is the focal, th lengthe greater is the depth of field.
Wide-angle lenses have a very large depth of field, which let us more clearly copy on the picture everything that is near, or farther from lens. Telephoto lenses are characterized by low depth of field.

f.eg.:D3S_9229-1200

All of those values, even after taking into consideration the size of the matrix of our camera, (and more precisely – the circle of confusion that result from this) contained in a simple formula let us create practical calculators:

I recommend this:

Untitled-1

http://www.cambridgeincolour.com/tutorials/dof-calculator.htm

It is worth using the field preview button, when we have already known what value of ‘thickness’ got the depth of our plan. Usually it’s located in the front, near the lens, as below:

front-12003
Depth of field extends asymmetrically with respect to the point at which the camera is focused. Behind this point the sharpness is much greater than from the camera’s side. It is very useful to know how it works, especially when the depth of field is equal, or sometimes is even smaller than the size of the subject.

A schematic range of depth of field for a ring:
1.  the focus is set involuntarily on the object that the most draw our attention while shooting- the ring is not within the focus range.
In the case of a rotary photography it is extremely unfavourable. The same drawing attention element will move and enter the bokeh.

depth-of-field3
2. the focus is set by the depth field preview – the whole ring is within the focus range , although the stone is not in the limelightdepth-of-field2

 

This can be best seen in printscreens (application MODEPIX/MODEVIEW)
The ring is seemingly blurred on the screen,

Zrzut ekranu 2015-01-12 13.17.23

although after setting off a preview of depth and using diaphragm 18, you can sharpen the whole picture.

Zrzut ekranu 2015-01-12 13.17.23-2

 

360-degrees presentations:

You can increase the depth of field in two more ways:
1. Optically- by using specialized tilt-shift lenses (link to the article about it)
2. Digitally- by using graphics programs, ‘focus stacking’ (link to the article about it)
Additionally, perfect edges of the object make the isolation from the background easier- link for the article about the free-form select.
It’s worth struggling, because after then you do not make such mistakes!

At = 1/160s, AV = 7.1 (too low diaphragm number for spinning rings!!!)

Written and photographed by: Dominika Apanasewicz www.studioavior.pl

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