Using Auto-ISO Feature to Make Life Easier When Learning Manual Mode


When you are learning how to shoot in manual mode, the effort to get each setting right to get the exposure and artistic element of the shot spot on can become quite overwhelming.

It can be quite demoralising too when you get shots that don’t match your expectations, especially in situations where you have to act quickly, like an event or shooting portraits or wildlife.

One of the features that can help you in this process is the Auto-ISO.

Simple speaking, Auto-ISO is a feature that lets your camera select the best possible ISO for a given shot automatically.

So you don’t have to worry about looking at the exposure meter.

You only concentrate on setting the Aperture and Shutter Speed and don’t worry about anything else.

Once you press the shutter button to take the shot, the camera will automatically detect the required ISO to give the perfectly exposed shot.

The Auto-ISO feature can be activated in most cameras right from the ISO function. On other cameras, it can be activated through the menu. Older cameras may not support this function.

Let’s take an example of how this function can make your life easier.

Let’s suppose you are shooting an event where there are a lot of people.

There is lot of movement, so you know that you have to keep a high shutter speed.

You know that almost all shots will look good at a wider aperture as a short depth of field will blur the background/foreground and keep the subject sharp.

So all you do is select the minimum aperture number, select Auto-ISO and then start shooting with a moderately high shutter speed.

Now all you have to change for different shots is the shutter speed (depending on movement of subjects and reciprocal rule).

Aperture will mostly remain the same and the camera will take care of the ISO.

So mainly you just focus on the shutter speed.

The tough task of keeping an eye on the exposure meter and selecting the right ISO is handled by the camera.

Now you may say that this is like shooting in the automatic mode.

It’s not.

In the automatic mode, the camera selects all the parameters on its own, not just the ISO. And the main problem in auto mode comes from the camera’s inability to select the right shutter speed, so the shots often look blurry.

When using Auto-ISO on the manual mode, you retain full control over the things that make the artistic different to your pics – aperture and shutter speed.

Your mind is taken off the ISO and you can use this freedom to focus on other important things like composition and movement.

Each shot you get will be exposed rightly.

To take another example, let’s say you saw a bird making some movements that you wanted to capture quickly. All you do is increase the shutter speed, reduce the aperture number and zoom in to take the shot. This will be very quick and will prevent loss of important shots.

Now what are the situations in which you should avoid using Auto-ISO?

The first problem is that Auto-ISO works very well in well-lit areas, but in areas where the light is less, the camera will end up selecting a high ISO which will produce noise.

But remember, if you were manually selecting the ISO, you would have selected a similar ISO to get the perfectly exposed shot.

So what’s the problem?

The problem is that when light is too low, we generally resort to using flash if we’re noticing that the shots are requiring a very high ISO.

When you use flash, the subject that is in front gets illuminated but the background doesn’t get enough of the light from the flash and is rendered darker.

To get the background well exposed too, it’s a must to increase the ISO or in other words, you have to deliberately overexpose the shot a bit to get both the subject and background to show up properly exposed.

You can use the function of exposure compensation to correct all this but we won’t get into that since that is slightly out of scope for now.

Bottom line is that you will have to be very deliberate about the ISO when shooting with flash. So letting the camera select the ISO on its own won’t be such a clever idea.

Here’s what you should do:

Test your camera in low light conditions at different ISO levels to find out the minimum acceptable ISO level that produces decent images without producing too much noise.

The better the sensor of the camera, the higher the ISO it can tolerate.

For instance, on the Nikon D5300, anything upwards of ISO 8000 is pretty much useless as there is a lot of noise.

So the correct plan of action to shooting in low light will be to set the maximum possible ISO you will let the camera select on the Auto-ISO mode. This can be done through the settings in menu.

So in this case, max. value of Auto-ISO would be 6400.

The camera won’t select anything above 6400.

If the light was very low and the shot required a higher ISO, the camera will just return an under-exposed shot.

If you are getting too many underexposed shots, it will be the hint to use your flash.

So that’s when you would disable the Auto-ISO feature. (Or you would see if the shutter speed is unnecessarily high. If it is the case, then reduce the shutter speed first to see if it works)

The other situation where you should not use Auto ISO is when you are shooting landscapes and still objects on a tripod, as there is usually no need to increase the ISO at all, as you can lower the shutter speed.

So it has to be remembered that using Auto-ISO is very helpful, but it should only be treated as an added weapon to your arsenal, as opposed to it being the only one.


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