ISO, aperture, shutter speed – take 2

Well, that was an interesting exercise… how did you get on?

Last time I briefly explained ISO (light sensitivity), aperture (opening size of shutter) & shutter speed. I then sat my toy dragon on a table inside in a well-lit area. I set my camera on “auto” – portrait (because I didn’t want background images to be focussed) and took a photo.

ISO: 100   Aperture: 4.5  Shutter speed: 1/160
ISO: 100   Aperture: 4.5  Shutter speed: 1/160

I then switched to manual mode , changed the ISO and took some more photos:

ISO: 200   Aperture: 4.5  Shutter speed: 1/160
ISO: 200   Aperture: 4.5  Shutter speed: 1/160
ISO: 400   Aperture: 4.5  Shutter speed: 1/160
ISO: 400   Aperture: 4.5  Shutter speed: 1/160
ISO: 1600   Aperture: 5  Shutter speed: 1/160
ISO: 1600   Aperture: 5  Shutter speed: 1/160

Personally, I prefer the 2nd photo with the ISO of 200 as the colours are brighter and there is more clarity to the dragon.  So now I will set the ISO to 200 and “play” with the aperture.

ISO 200 Aperture f5.6 Shutter speed 1/160
ISO 200 Aperture f5.6 Shutter speed 1/160
ISO 200 Aperture f6.3 Shutter speed 1/160
ISO 200 Aperture f6.3 Shutter speed 1/160
ISO 200 Aperture f7.1 Shutter speed 1/160
ISO 200 Aperture f7.1 Shutter speed 1/160
ISO 200 Aperture f8 Shutter speed 1/160
ISO 200 Aperture f8 Shutter speed 1/160

So with ISO 200 and shutter speed constant on 1/160, the aperture is best on f6.3.

Now let’s play with the shutter speed leaving the ISO constant on 200 and the aperture set at f6.3.

ISO 200 Aperture f6.3 Shutter speed 1/40
ISO 200 Aperture f6.3 Shutter speed 1/40
ISO 200 Aperture f6.3 Shutter speed 1/60
ISO 200 Aperture f6.3 Shutter speed 1/60
ISO 200 Aperture f6.3 Shutter speed 1/100
ISO 200 Aperture f6.3 Shutter speed 1/100
ISO 200 Aperture f6.3 Shutter speed 1/125
ISO 200 Aperture f6.3 Shutter speed 1/125

Now, I don’t know that I have really come to any conclusions but it has been an interesting exercise anyway 🙂 I have it set in my mind once again, after many years of using auto mode, that ISO is to do with light sensitivity and basically, the brighter the light, the lower the ISO, the smaller the aperture (f-stop) and the faster the shutter speed.

So, to go to the other extreme but staying with ISO, aperture and shutter speed, my next exercise will be to take some similar photos at night with little or no light. Of course, I will need to set the camera on a tripod for this…

ISO, aperture and shutter speed

As I said in my introduction, I am going to take you through my (re-) learning curve with my DSLR.  I am using numerous websites to find the info to explain it briefly and succinctly. I do hope I have the facts correct (if not, you are welcome to correct me – politely, please). We all know “practice makes perfect” and one doesn’t learn to play tennis or golf or any sport by simply reading the “How to …” manual.  So when you think you have a general idea of what I explain below go for it and shoot away – you can delete every photo, your bank balance won’t be affected and no one need know 🙂

  1. ISO:

Question:  How do we say “ISO”?

Answer: “eye-so”.

Question:  What does ISO stand for? Does it matter?

Answer: No… so we’ll move on. (You can find that on many websites if you really are interested!)

Question:  What does ISO do/mean?

Answer: ISO is to do with the light required in a photo or ‘light sensitivity’. The ISO on my camera (Canon ESO 650D) ranges from 100 – 12800. The lower the number the more light is required. A low number would be used in bright sunlight or when using a tripod. BUT… ISO is always balanced with…

2. SHUTTER SPEED

Question: What is the “shutter speed” dial/tab/button on the camera?

Answer: It is the fraction on your screen.  Mine ranges from 1/4 to 1/4000.

Question: What does each fraction mean?

Answer: A fraction of a second.

Question: What is the relevance of fractions of a second?

Answer:  The higher the number (fraction) the slower the shutter speed i.e a setting of 1/4 means that the shutter opens and closes very much more slowly than a setting of 1/4000. Or looking at it the other way, the bigger the number on the bottom (4000) the faster the shutter opens and closes.

(Gosh, no wonder one gets confused!!)

Question: When and why do we need different shutter speeds?

Answer: Because life is not static! We can use a slower shutter speed (1/4 e.g.) when photographing landscapes or using a tripod but we will need a fast shutter speed (1/4000 – well, towards that end of the scale) when capturing an action shot.

Question: How do the ISO and the shutter speed interact?

Answer: Hold on… there is a third element to what is commonly called the “Exposure Triangle” (sounds we’re into something secretive now!) and we must look at all three elements together …

(Hey, I remember all this from my pre-digital SLR days!)

3. APERTURE

Question: What is aperture?

Answer: The definition of ‘aperture’ is ‘hole’ or ‘opening’ or ‘gap’ so in your camera it is the opening through which the light travels when you click the button. The aperture can be compared to the pupil of your eye… when you are in bright sunlight your pupil is smaller as it doesn’t need to let in as much light as when you are looking for an object in a dark room.

Question: What is the label/dial/button that adjusts the aperture on my camera?

Answer: The “F-stop”. On my camera it goes from F4.0 to F25

Question: What do the numbers mean?

Answer: The numbers adjust the size of the aperture/opening. And here is the important thing… the lower the number the larger the opening. (Now that should be easy to remember – lower = larger :-))  And if we looked at the actual opening we would see that the smaller the opening the less exposure. (Sounds confusing but it does makes sense!)

Question: So why do we need to adjust the size of the aperture?

Answer: For the same reason that our pupils adjust their size according to the light.

Question: So how do these three (ISO, Shutter speed & aperture) interact?

Answer: Before I answer that I will re-cap briefly then go and take some shots playing with the different settings…

ISO: Lower = less exposure: 100 = less exposure   12800 = more exposure

SHUTTER SPEED: Slow (1/4) = more exposure   fast (1/4000) = less exposure

APERTURE: Small (f4.0) = less exposure   Large (f25) = more exposure

Have fun & I’ll be back real soon with some of my shots 🙂

Why write a photography blog….

I have been an amateur photographer since I was about 10 years old.  My father was a keen photographer & also my mother’s father. So I guess it’s in the genes.

A small collection of cameras and accessories dating back to my grandfather's camera.
A small collection of cameras and accessories dating back to my grandfather’s camera.

I remember my first camera – no, not a Box Brownie, but a similar-aged model which took a reel of 12 black and white photos on film, of course. My father taught me not to “waste” photos as each, good and bad, cost money to develop.  He never hesitated to pay to develop my films but he certainly wasn’t impressed if there were too many “dud” shots on a reel.  I still have a few of those photos in albums and think, for a child, they’re okay.

I progressed through two or three cameras during my teenage years and joined the Camera Club at Teacher’s College where I learned how to develop my own photos and other topics relevant to composition and so on. On graduation from Teacher’s College my father gave me a (second-hand) “real” camera – one that did more than “point & shoot”. This camera served me well over many years until I bought myself my first SLR. I taught myself how to use this and still enjoy reflecting on many of the photos taken before the advent of the digital camera.

With the “advance” to a digital I promptly forgot all I had learned regarding ISO, f-stops and aperture sizes, etc, etc. The digital auto-mode did it all for me 🙂 Now, 15-or-so-years later I have, after having owned a DSLR (digital SLR) for 3 years, decided it is time I taught myself how to use the manual mode! Unfortunately, my memory does not serve me well and I really do have to go back to the beginning.

I loaned my Seagull SLR to various friends and family members and now it has disappeared off my radar as has my first digital – oh well, they’ll probably re-surface one day when I’m long gone!

I have read several books, including my camera manual (well, parts of it), and started a couple of on-line photography courses (I got lost!) and visited many websites on cameras and photography (some are excellent, some not!). I decided that I must go back to basics and relearn (from Youtube clips and websites). Joining the local Photography Society is another step forward. Then, if I write, as simply as possible, what I learn I will not only consolidate it to myself but may just help others also. Honestly, at this stage, finding my way around menu, dials, options and controls is almost as daunting as learning to fly an aircraft!

Next post…. ISO, f-stop, aperture sizes and shutter speeds 🙂