Understanding Aperture – Photography Tips

Hello All

Only a little update this week.  This week I have not taken many photographs, a good job really, I have been so busy booking in newborn sessions and weddings for 2015. I had a wonderful time at the Northants Baby and Toddler show and personally spoke to over 50 families, I will be meeting quite a few of them with their new babies quite shortly! Before we have a look at our next little tutorial a little update on the Bluebell Wood Shoot.

Bluebell Wood Photography

Time To Book Bluebell Wood Sessions

It really is time to book this years Bluebell Woods Shoot. Session fees cost just £45 for an hour. If you would like a current brochure detailing our prices please CONTACT ME  and I will send you an e.mail version. Session fees include the session and custom edit of your images. If you wish to book please do so online HERE.

Understanding Aperture

So today we are going to have a look at Aperture, the last of the three components that make up the ‘exposure triangle’. If you have been following my blogs you should now have a little understanding of Exposure, ISO and Shutter Speed. If you want to recap any of the blogs please click the links.

So now we are going to look at Aperture. This is the last component of our exposure triangle. The three factors that combine to create an exposed photograph. The cameras aperture setting as with all these components is just another control that increases or decreases the amount of light that hits the image sensor or film. This time though it is the light that comes through the actual lens. Very simply put the aperture is a hole within the lens, through it light travels into the camera body passing through the cameras shutter before it hits the sensor or film.

The aperture can be a small opening or a large hole. A good way of visualising the aperture is to think abour your eye. The aperture is like your pupil, in bright light your pupil shrinks to limit the amount of light that hits the back of your eye. In a dark room your iris with widen to let in more light. That is as simple as it gets.

This is an image of what the aperture ‘hole’ looks like through a lens.



Mostly this is where you throw the manual out of the window but don’t! The size of your cameras aperture setting is specified in terms of an f-stop value. These values take a little time to get your head around only because a smaller f-stop means a larger aperture while a larger f-stop means a smaller aperture. Have a look at this image (image couresy of Wikipedia)



The size of the circle represnts the size of the lens aperture – the larger the f-stop the smaller the aperture.

It does take a while for this to sink in but once you start using your camera creatively on manual, over time you learn that f/22 is a tiny aperture and f/4 is a large aperture.

Depth Of Field

When we looked at shutter speed we looked at how manually using shutter speed allows you to visually interpret motion in different ways. Variations in aperture has a different visual outcome. Variations in aperture effects an image’s depth of field. Depth of field simply relates to the area of an image that appears sharp. A very small aperture such as f/22 or f/32 will create images with a large depth of field. I leanrt to remember this by thinking of a pin-hole creating crisp images. If you are photographing a landscape and want the foreground and the distance in focus you would use a large f-number (f/22). If however you want to isolate the foreground from the background making the foreground objects sharp and the background blurry you will need a small f-number (a wide aperture). For my new born baby photograps I usually shoot at f/2.8 for a really shallow depth of field. This allows details like fingers and toes to be in focus while blurring the backgrounds.

Shallow depth of field

Have a look at these two images of my son, of course he is giving me his ‘camera smile’ the first shot is taken at f/8 and gives me quite a wide depth of field, you can see focus detail on his nose through to the back of his head and his shoulders are still in focus, the background is also quite visible and you can see the detail on the radiator behind. Look at the difference in the second shot, this was taken at f/1.4 and has given me a shallow depth of field, only his left eye and part of his mouth are clear and in focus, his shoulders and back of his head are completely blurred and you can see almost no detail in the radiator behind.



Lens Apertures:

Aperture is slightly different to ISO and Shutter speed in that it is found within the camera lens. Every lens varies and has a limit on how large or how small the aperture can get. If you look at your lens specifications it will say what the maximum (lowest f-number) and minimum apertures (highest f-number) of your lens are. The maximum aperture shows the SPEED of the lens. This is important as a lens that has a small f-number of say f/1.2 or f/1.4 is considered to be a FAST lens because it can let in more light than, for example a lens with a maximum aperture of f/4.0. The fast lenses are much better suited for low light photography and you will see a big difference in price between lenses that have the same focal range but a bigger maximum aperture. Look at the differences in price between these  50mm lenses:

50mm f/1.8  £73.0091fYqb6yGBL._SL1500_81oJH68AHCL._SL1379_-1


50mm f/1.8: £73.00

50mm f/1.4: £257.00

50mm f/1.2: £1146.00

We will look at lenses in a later blog. The important thing here is to understand is how creative use of aperture will effect how you image will look visually in relation to depth of field.

Give It A Go.

The easiest way to see how your aperture effects and image is to set up some close up photography.

Lets place a series of objects on a table, I have used books for this demonstration.

This time set you camera’s dial onto AV or ‘A’ for Aperture Priority mode, this may just be an A on your dial, see the image below. You don’t need to fully understand what you are doing but this creative function on your camera will put everything else on your camera to ‘auto’ except your Aperture.


Get low to the table edge, keep all the books in frame, adjust your aperture so the reading is at its highest, around f/22, and focus on the end book, and take a photograph.With your camera on the same settings and with the same amount of books in the frame re-focus on the book in the middle and take a photograph, now do the same and focus on the book at the front.Take a look at your images. There shouldn’t be much difference in focal point of any image. It doesn’t matter where you focus, the full line of the books are in focus, the depth of field is wide.

IMG_9960-1 depth of field-1 depth of field-2

Now adjust your aperture to f/4, and repeat the above keeping as best you can the same amount of books in the frame. Focus on the same end book, middle book and front book. Now look at your photographs. You should see a difference in the depth of field in each of your three images. The focal point of each shot has changed depending on where I have set my focus, at the end of the books, the middle of the books or the first book. The depth of field is shallow.

depth of field-4 depth of field-5 depth of field-6

This of course has fantastic creative uses, if you want to take a portrait of someone it is much nicer to have a blurred background so you are focusing on the person, if you are photographing a landscape though, and want the full range of landscape in shot from the foreground ridge you are standing on right through to the mountain range in the distance then you really want a small aperture so every detail is in focus. I would not photograph group shots at a wedding for example on f/4, I would run the risk of the wedding guests at the back of the group being out of focus. I tend to shoot group shots on f/5.6 and as discussed, I always focus my newborn baby and child sessions with a shallow depth of field, around f/1.2 or f/1.4 to get the little details in focus with a real softness to the backgrounds.

014-Stanley 015-Stanley

Aperture And Light

Of course changing the aperture on your camera will effect how you must set your other two parameters to get an exposed photograph. A small aperture of around f/16 or f/22 will let in a very small amount of light so you would have to slow down your shutter speed respectively. Conversely a wide aperture of around f/4 will let in a large amount of light so you would need to selects a faster shutter speed. We will look at how these three components work together in a later blog.

So hopefully that will have given you a little understanding into aperture. Now armed with your knowledge of ISO and Shutter Speed, we are ready to bring it all together. Have a play though with your camera’s aperture first!

Happy snapping

Kyra. x