Ask Uncle Ronnie – August 2017


Going below ISO 100
When I check the EXIF data in some photographs in various magazines, sometimes the image is taken at ISO 50. I own a Nikon D5300. In it, the minimum ISO setting is 100. Is it possible to go below this ISO in my camera? Or is this possible only in high-end models? Is there any calculation/ formula for setting ISO below 100? If yes, kindly explain in details.

Dhananjay Ingle, Indhan.

The minimum ISO sensitivity on your Nikon D5300 is 100. You cannot go below this.

Why high shutter speeds?
In SP July 2017 issue, there are several black & white photographs from page 35 onwards. In all these photos, although the lens focal length is not mentioned, the data given are as follows:

Aperture: F/3.6 Shutter speed: 1/320sec ISO: 500

Aperture: F/5.6 Shutter speed: 1/2000sec ISO: 500

Aperture: F/4.5 Shutter speed: 1/2500sec ISO: 2000 etc

Photos are of street scenes and there’s no need to use fairly large apertures. I am curious as to why the photographer used these apertures, with high shutter speeds. Could it be due to using the Programme mode?

Newton Wickramasuriya, Sri Lanka

With street photography, you are never sure of any sudden, unforseen movements by the subjects. Hence, to avoid the possibility of blurred images, higher ISO sensitivities are often used, which in turn allow for higher shutter speeds to arrest movement. The photographer may also use wider apertures to control the depth of field as he/she deems appropriate for the scene. And wider apertures allow for faster shutter speeds!

Pan & Tilt Head

Heads for Tripods
I notice that you mostly suggest a ball-head for a tripod, and not a pan & tilt head. Are there any problems with using a pan & tilt head?

Rawal, via email

There is nothing wrong in using a pan & tilt head; a ball-head is quicker to use. A pan & tilt head can be 2-way or 3-way. A 2-way model…

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