This is a question I get asked a lot on photo safaris and there just is not a hard and fast answer.
For some reason many people get stuck on ISO and the role it plays while out on safari. If you find yourself asking this question it might be worth your while to take a few minutes to remind yourself of the basics.
Most of the people who ask this questions have already moved away from shooting in Auto and are shooting in Aperture Mode os Shutter Speed mode. This means that they have taken control over one of the variables – Aperture or Shutter Speed – and your camera will make the necessary adjustments to the other in order to keep exposure the same.
The shortest possible answer I can give you with regards to how high your ISO should be is that it should be as high as necessary but as low as possible.
But what does that mean?
Your ISO should be as high as necessary to give you a fast enough shutter speed.
Your ISO should be low as possible in order to minimise digital noise.
Does that make 100% sense?
If so, you more than likely have a good understanding of the relationship between ISO, Shutter Speed and Aperture.
If not, here is a recap of some of the basics.
- Shooting in Aperture Mode, which most people seems to be doing, you control Aperture.
- The camera will make changes to your Shutter Speed in order to keep the exposure the same.
- You can see the Shutter Speed that the camera has calculated through your viewfinder.
- You should always try and keep your Shutter Speed to at least 1 over your focal length.
- This means that at a focal length of 200mm your Shutter Speed should be at least 1/200.
- If your Shutter Speed is too slow – under the above guideline – you stand the chance of getting soft images.
- If your Shutter Speed is too slow then start thinking of adjusting your ISO.
- By increasing your ISO your camera sensor will be more sensitive to light.
- A more sensitive sensor will result in the camera calculating a faster Shutter Speed.
- A faster Shutter Speed will result in sharper images.
ISO in itself should not be your main concern when heading out into the field. Aperture, DoF and Shutter Speed are the things that you should really be thinking about as they will directly influence the look and the feel of your images and are the technical tools you can use to creatively tell stories. As long as you don’t blow your ISO out of the water and understand when and – most importantly WHY – you need to change you will be on the right track.
I know a lot of people get very caught up in the technical side of our craft and that’s ok. Even though I personally gravitate towards the creative side of photography, the art side, I definitely appreciate that a solid technical foundation is important but not just for the sake of knowing your apertures and shutter speeds. It is important to know and understand the technical details as it will give you a much better platform from which to create interesting images. The better you know your tools the better you will be able to use them.
When you look at this image, does it really make a difference what ISO it was shot at? Is that the first thing you think of?
The world does not need sharper images.
The world needs better images.
Knowing the basics of ISO and how it affects Shutter Speed will help you achieve this.
Later this week I will look at the two other questions that also come up quite often. The first is “What should my Shutter Speed be?” and the second is “What should my Aperture be?” Both of these questions will be answered with a question but we’ll get stuck into that in the next post.
Until next time.
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