‘M’ is for Manual Photography Week 2 – F-Stops and Shutter Speeds


F-Stops on my Leica M8 start at F2 then move to F2.8, F4, F5.6, F8 and up to F16..

Hello Manual Enthusiasts,

Thanks for joining me again in this foray into manual photography. In case you missed last week ‘Your Camera‘ you can catch it here.

Today I am just dealing  with the two subjects that control light coming into your camera, F-Stops and Shutter Speeds.

Now I am going to show you how things work on my Leica (which has fewer buttons and gadgets like analogue camera’s had) and is much simpler to get your head around than all the digital numbers that appear on our LCD screens.

Tomorrow’s post will be about Depth of Field and Exposure so stay tuned.

What is an F-Stop??

You will see on the lens above that there are numbers 2, 2.8, 4, 5.6 and they keep going on this camera right up to F16. These numbers are the F-stops and by moving the ring and selecting a different number you are opening or closing the lens and letting more or less light in to the camera.

Now heres the confusing thing for us girls. A bloke designed this for sure because in my opinion it’s the wrong way around.

Small numbers like F2 or F2.8 mean ‘more light’ entering your camera and high numbers like F16 means ‘less light’ entering your camera.

Now wouldn’t it have made more sense to do it the other way around???

So you have to think like a bloke (illogically.. ha ha guys) when you want more or less light

Small numbers = equal lots of light

High Numbers = not much light

What happens when you go from F2.8 to F4? Basically you are halving the light that enters your camera.. If you go from F2.8 to F2 you are doubling the light. Just a little detail to know that as you move along the scale from one F-Stop to the next you are doubling or halving the light entering your camera. This can be a big deal and save your shot if you are working with low light (that’s why good camera lenses cost a lot of money because they have low F-Stops such as F2).

Have a look at the image below and you will see the black circles are the lens and the white circles are the lens openings. You  will see at F22 the opening is really small (not much light coming in) and F2.8 really large (loads of light coming).


fstops demystifiedImage via Pinterest

Now on fancy digital SLR cameras you no longer simply move the ring on the outside of the camera (unless you are lucky) to change F-Stops you have to use one of your selectors. Now in my case on my Canon 5D I use the wheel on the back of the camera to select the F-Stop. See image below with stars!

So if you are looking into your viewfinder and move this wheel (on my camera yours may be different) you should see the numbers changing along the bottom of the image.

wheel to change f-stop


Shutter Speed

I love shutter speed! It’s the area where we get to choose whether we want motion blur or our action frozen in time…

The shutter wheel dial again on my Leica is just a simple wheel and this is how you should think of shutter speed even if you have a fancy digital SLR.


 Shutter speed wheel and values on my Leica M8

Shutter speeds work in fractions of a second and as you move up the scale from  1/30, 1/60,1/125/1/250, 1/500 you are doing two things:

1. Letting less light into your camera because the speed is faster and the shutter is open for less time

2. Changing how your image is captured. The higher the shutter speed such as 1/500 the more likely movement in your photo will be frozen, at a 1/30 second you will have lots of blur.

wayne chick 4

Image shot at 1/30 second. You can really see the blur here..

Carla Coulson Wayne Chick

Shot at 1/125 second.. Here she is moving towards me and curtseying so  there is a little movement of her hair etc but you can see the dress clearly unlike in the top shot.

Some examples:

1/30 second –  Great if you want camera shake or movement blur

1/60 second – If you don’t have steady hands anything from here down (1/30 etc) will have camera shake and motion blur when capturing movement

1/125 second – My starting point if I don’t want camera shake and when I want to capture slow movement without too much blur

1/250 second – Good for freezing movement such as fast walking or slow biking

1/500 second – Good for freezing movement of a car or scooter

1/1000 second – Good for freezing movement of a Ferrari

1/2000 second – Good for freezing movement of a Lamborghini!

How to change your shutter speed on your fab digital SLR?  On my Canon 5D I need to use the wheel on the top of my camera. When looking through the viewfinder I can see the shutter speeds changing as I move the wheel. On your camera it may be in the same position, if not you need to locate it.

I think that is enough for today!  I will be posting Exposure and Depth of Field next week so stay tuned.

Have a great day.

“I wish more people felt that photography was an adventure the same as life itself and felt that their individual feelings were worth expressing. To me, that makes photography more exciting.” Harry Callahan




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La Contessa
8 years ago

I agree………A BLOKE.
I have always liked my photos at 125!
This all made good sense to me……..THANK YOU!
Now,what country are we thinking about???

Rae Ecklund
Rae Ecklund
8 years ago

Oh, thank you for this!!!!
How can I see the first installment of instruction?

Thank you for speaking our language!

8 years ago

I think the doubling /halving is back to front


Susie L
Susie L
8 years ago

Dear Carla, thank you so so much for sharing your knowledge. You are such an inspiration. Have a wonderful weekend.

8 years ago

Carla, a good guide for someone still grappling with the wrong-way-round F stop thingy! Shame the F stops measure the outer rim (aperture shutter ring) rather than the hole in the middle. I try to see it (the blokes’ way?) as small number means there is very little of the aperture ring shutting down the hole. But I still have to do a double think about this. Why oh why didn’t the inventor of the terminology measure the centre not the edges?

Btw, I was confused by your note:’What happens when you go from F2.8 to F4? Basically you are doubling the light that enters your camera.. If you go from F2.8 to F2 you are halving the light.’ I thought it was the other way around. F2.8 lets in more light than F4. OMG, am I still getting it wrong?!

8 years ago

I think you explain this so much better than my ex – a brilliant professional photographer! Xcat

Anya Jensen
8 years ago

I have never gotten to terms with the shutter speed – this explains it so much better than everything else i have read:-), so I’ll just have to go and test. Thanks a mill for sharing Carla and have a great weekend,