Photo Tip “Zoom Effect”

Photo tip – Use the zoom effect for dynamic photos of motion

The zoom effect is an interesting creative option to give an image a dynamic component. This is achieved by the focal length being changed during exposure (zooming).

With this technique, the image result is somewhat charged by coincidence. This is partly because on most cameras you can’t see anything through the optical viewfinder while the image is being captured. The image results often surprise with interesting dynamic image effects. All that is required to capture creative images with this technique is a mechanical zoom (all digital SLR cameras that have a zoom lens) as cameras that have a mechanical zoom that lock the zoom at the moment the image is captured. This aspect could also be a deciding criterion when looking for the right camera. In order to find the right camera, you will find a range of different relevant criteria and features of cameras in the article “The right camera – Some purchase advice”.

The effect the zoom has is to move image elements from the centre of the image to the edge of the image. The closer an object is to the edge of the image; the more it is shifted and blurred. For the zoom effect, relatively slow shutter speeds are required therefore this technique is often associated with motion blurring.

Practical implementation in photography
Fundamental technique

  • Adjusting of focal length setting during exposure
    • You can start zooming before capturing the image, after setting the focus
  • The effect depends on shutter speed
    • Possibly use tripod
    • Relatively slow shutter speeds are required here. To achieve longer periods of exposure without overexposure, there are various options:
      • Use of poor (dark) lighting conditions
      • Small diaphragm diameter
      • Low ISO rate
      • Possible use of ND filter
  • The effect depends on zoom speed
    • During short periods of exposure you need to zoom with increased speed – when using slower shutter speeds, the focal length can be changed more slowly 

Further technique

  • For the image effect, it is a good idea to leave the zoom settings untouched for a short moment – this makes the image sharper as well as the object that is being photographed – this decreases the abstract effect caused by the zoom

 The following night image of a petrol station was captured using a zoom effect.

zoom effect for dynamic photos of motion

Information about example image
Gear

  • A monopod would have been an advantage – however, no monopod was used for this image

Technical settings

  • Focus
    • Focus can either be set manually or automatically depending on preference – it has no impact on the image result
  • Program mode auto exposure (P)
  • Diaphragm 1:5.6
  • Exposure time – 2 seconds
  • To achieve this zoom effect, the zoom speed has to be aligned with the exposure time. The period of exposure shouldn’t be too short. However, if the shutter speed is too slow it can result in unwanted blurring.  The best thing to do is to take a few test shots with comparably fast objects at the same distance, motion angle and focal length.
  • ISO rate – 100 ISO
    • By adjusting the ISO rate correct exposure with a desired time-diaphragm combination can possibly be achieved.
  • Focal length and zoom
    • Focal length change during exposure from 85mm to 17mm (ca. 135mm – 28mm 35mm equivalent focal length)

The zoom effect can also be created in image processing programs. The advantage of this technique is having full control over the image result. The image processing program must have the following:

  • Selective options
  • Radial blur filter
    (The articles on this topic are being prepared)

Here is another example of the zoom effect. This effect was also created while the being captured by adjusting the focal length.

Zoom effect – Rose – 2009

Exposure: 1/6 second
Starting focal length: 24mm

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