I could imagine you looking all over your camera to find this magic mode. If there really is a magic mode, why didn’t label it as magic? Actually it is quite obvious, you just don’t realize it. But before I reveal the magic to you lets just make sure you have everything in the bag.
Exposure consists of three parameters which are shutter speed, aperture, and ISO. Shutter Speed Priority Mode is whereby you control the shutter speed while the camera finds the appropriate aperture. Aperture Priority Mode is the opposite of Shutter Speed Priority Mode where now you control the aperture and the camera selects a proper shutter speed. Check.
But all this while we haven’t talked a great deal about ISO and its implications on exposure. Traditionally ISO or film speed isn’t much talked about when it comes to exposure mainly because it is constant once you load up the camera with film. The film would have a speed rating (e.g ASA/ISO 100) and you couldn’t change the speed unless you change the whole roll of film unlike now its just a turn of a knob. But this convenience has caused even more confusion to beginners as they would have three things to worry about (shutter speed, aperture, ISO) rather than just two. Photographers that started out with film would deeply appreciate the ability to change ISO on the fly and not having to waste time and film.
*Photographers measures light differently than say torch light manufacturers. While they require to make their products’ brightness according to units like lumen or x candles, photographers think in relative terms. In short we measure light with “stops” or specifically “f stops,” Remember that we have more things to think about (shutter speed, aperture, ISO) so “f stops” makes more sense than say “this exposure looks like 3000 candles bright to me.” So, in photographic context, this 3000 candles bright could be 1/60s, f4.0 at ISO 400. Honestly who (other than torch light makers) could imagine what 3000 candles brightness could be?
So, take for example now that you have an exposure of 1/60s, f4.0 at ISO 200 and you realize after taking a shot that the image is not sharp and might be cause by your hands not being steady enough. Now what do you do? Raise the shutter speed right? Yes but then your image will become darker (underexposed) as there would be less light hitting your sensor with a faster shutter. You could open up the aperture to compensate but what if f4.0 is the maximum aperture of your lens? Last resort – ISO.
Base exposure :
1/60s, f4.0, ISO 200
You need to raise the shutter speed by one stop (from 1/60s to 1/125s)
1/125s, f4.0, ISO 200
But now you image would be 1 stop underexposed so to compensate you raise the ISO by 1 stop
1/125s, f4.0, ISO 400
And we’re all set. See how easy it is to shoot without having to change film(change ISO) or use flash (to add more light) just at a turn of the knob. You could do all this while still in Shutter Speed Priority Mode. But little do we realize we wouldn’t even realize this problem at all if we have set the ISO to auto. And this is where our Magic mode comes to reveals itself.
If we could have Shutter Speed Priority and Aperture Priority, why can’t we have Shutter Speed AND Aperture Priority? And now we could by using, yes you have guessed it right, the Manual Mode. I am not making a u-turn here by being a purist-wannabe here but with Auto ISO feature – one could unlock so much more control over their exposure that was just not possible before.
Why would we want Shutter Speed and Aperture Priority Mode? Here is an example :
1/125s, f11.0, ISO100 (Manual Mode + Auto ISO)
Here is a situation where I needed a relatively slow shutter speed for the panning effect but because a car is a big subject, plenty of aperture is needed if I want to retain sharpness from front to back. And also because the light level kept changing throughout the day (already falling to a low level here), I would not want to worry about exposure but I do want to worry about depth-of-field. If I shot this with Shutter Speed Priority, the camera might have selected a larger aperture of f4.0 for example and would made focusing much harder and failing to secure good sharpness from front to back.
This is just one example of using Manual with Auto ISO to shoot creatively and there are still many other situations where this way of shooting is superior compared to other modes. So far we have come to understand to make pictures we can improvise and the Auto ISO has accidentally led us to a new discovery. Controlling two parameters and letting the camera do the work on getting the right exposure is fantastic to say the least. But of course there are more to this and next article we will go into another way of shooting while controlling all three parameters while still getting proper exposure.
As always, we still turn heads with our pictures – they turn knobs and wheels.