Getting away from Auto, and going into Manual Mode
First off, let us talk about why we want to move away from Auto mode, and use Manual mode. When you use Auto mode, you give your camera all the decision-making power of how the shot will come out, this gives your camera the ability to choose the shutter speed, aperture and ISO for you. Now the problem with this is that the camera can only assess the light entering it, and based on that it can figure what ISO, aperture and shutter to use. However well that might work, it will not always be correct, for example, if you are shooting a sport scene on an overcast day where you do not have too much light, the camera might decide to rather decrease shutter to allow for more light to enter, but it will not realize that you need a faster shutter speed to capture the motion and avoid blur.
In conclusion, our main reason for leaving Auto mode behind and going for Manual mode is to ensure we have all the control we need, we can decide what needs to be set, and why. We are in charge of it all, and this is a great way to start getting our creativity flowing.
What you need to know about using manual mode
From my previous blog post Aperture Priority Vs. Shutter Priority Mode, we talked all about Shutter speeds and Apertures, so we have a handle on that by now, and a basic understanding of what each one of them does, and how they work and affect each other. If you have not read it, just follow the above link.
Now as you know, in manual mode you can set your shutter, aperture and ISO. As we already discussed aperture and shutter, let’s now focus on ISO. This is another way to help you take shots when you need more light, but it is very important to remember that the higher you go with your ISO, the more “noise” you will introduce into your image(which makes your image look grainy), so in my opinion a high ISO setting should always be your last resort. That being said, sometimes a higher ISO will be your only option. Let’s use the same example again, shooting a sport scene in low light conditions, in auto mode the camera might change the wrong settings, and your images will look sub-par at best, but in manual mode you will be able to choose the settings yourself, instead of the camera lowering the shutter speed, you might decide to rather increase the shutter, so you can freeze motion, and also increase your ISO so you still have enough light, while using a wide open aperture. This will give you the shot you made in your head, with this control you have the freedom to adjust everything the way you want and become more creative with your images too.
Now that you understand all the main components involved with manual mode, let’s look at how to make sure you still get the correct exposure you wanted by using and setting your desired settings.
Manual Mode Exposure Meter
Having a look at the above image will give you a great idea of how shutter, aperture and ISO work together to create your exposure. In the first one our meter is on zero, which means we have made a correct exposure. There we have used 1/125 shutter, f16 aperture and ISO 200. Now if we look at the second image you see that we dropped our aperture to f11, which means our image will now be overexposed by one full stop. In the third image we have an aperture of f22, and that will now give as image underexposed by one full stop.
Next let’s just concentrate on the first (correct exposure) image and explain more on the shutter speed and ISO. By only changing the shutter speed, how will we get the same exposure results? Decreasing the shutter speed to 1/60 will give us a full stop overexposed as in image 2, and increasing the shutter to 1/250 will give us a full stop underexposed image as in image 3.
Same thing can be done with our ISO. To get the overexposed image as in image 2, we can increase our ISO to 400, and we have a full stop overexposed image, or we can decrease our ISO to 100 and we will have our full stop underexposed image as in image 3.
Keeping all of this information (I know it’s a lot) in mind, we have now seen how every setting you change will affect your exposure outcome. And with this knowledge we can now establish what will happen when we change each setting, and what is necessary to be changed to get a correct exposure, but still keep the settings we need to get our perfect shot intact.
Most important to remember: If you decrease the shutter speed, you need to widen (lower f-number) your aperture by the same amount of stops to keep your exposure unchanged, which means when you increase the shutter speed you need to narrow (higher f-number) your aperture by the same amount of stops. When you double your ISO you need to either use a narrower aperture (one full stop) or a faster shutter speed (one full stop) to maintain your exposure, the opposite goes for decreasing your ISO.
Well guys, that’s about it. I hope this gives you some insight into using manual mode, and why it is better than auto mode.
Feel free to ask me any questions you might have in the comments and I will answer what I can.