DEPTH of FIELD:
Depth of Field (DoF) is one of those subjects that can seem to be very complicated…because technically, it is. DoF has to do with factors such as what lens is on your camera and whether or not your camera has a full-frame, or cropped sensor…and that is just scratching the surface! Again, in trying to keep things basic, so they can be understood well, I will not be getting too much involved in the specifics, but will Keep It Super Simple for you to be able to understand and then use the information presented here.
The simplest definition of Depth of Field is the area of your images that is in acceptable focus. More specifically, it is the distance between the nearest and farthest objects in a scene that appear acceptably sharp.
The shallowness of Depth of Field depends on the f/stop used (also known as the Aperture: f/2.8, f/8, f22, etc.), the focal length of the lens on the camera (24mm, 50mm, 100mm, etc.) the size of the camera sensor (full-frame or cropped) AND the distances between you and your subject, and your subject and the background.
Got it? Good! No? OK.
Then let’s look a bit closer…
DoF is where creative control comes in to play; and allows for that soft, dreamy look in a photograph that everyone seems to enjoy – like the image I created for this post. Knowing how to achieve creative control with DoF is probably the most important aspect about photographing that people want information on. Once you understand DoF, a world of creativity opens up!
If you read my post about equipment, specifically the information on lenses, this is where they become really important.
In your mind, you have this wonderfully creative idea where you want to create an image that is magical; where the selective-focus in on your subject (that beautiful flower) and everything behind it is totally out of focus and so dreamy.
So, you reach for that Canon EF-S 18-55mm f/3.5-5.6 Lens that came in the kit with your camera, and…
The problem with that lens is three-fold:
1. It is a wide angle- (18mm) to normal-view (55mm) lens,
2. At 18mm, the biggest f/stop available is f/3.5, but at an f/stop of f/3.5 at 18mm, it is quite difficult to achieve that soft dreamy selective-focus look you want because wide-angle lenses aren’t necessarily built for that – they are built to get everything from where you stand to Timbuktu in focus! But, then there is the next issue…
3. At 55mm, the biggest f/stop available is f/5.6, which is going to make it near impossible to achieve that selective-focus as well, because at f/5.6 and 55mm, the f/5.6 Aperture (f/stop) is designed to ensure you are going to have as much focus of your subject as absolutely possible.
The kit lens are built for a win-win get everything in focus so the user has a lot of success, but a no-win situation if you are wanting to achieve that dreamy selective-focus effect. This is why I like to encourage those who love photography and want to enjoy it further to invest in a Prime lens that is Fast – because it will allow for more creativity, which leads to more success and even more enjoyment!
Win-win; that’s what I want you to go for.
So, you only have a kit lens…”what’s the best way to use it?” you ask…
Well, use it – it’s designed for outside use mostly (again, because it’s not very Fast). Try different angles, get a lot of distance between your subject and the background while you are as close to your subject as the lens can focus (a whole ‘nother issue!); see what happens when you shoot like that – you should get a little better blur to your background, but still, it may not be enough for what you are hoping to do, but don’t be afraid to try it, at least.
Here’s a couple of examples I “borrowed from the web” on DoF.
This first example is of Fast lenses and the amount of focus (indicated in red) you have to work with at f/2 in each of the various lens focal-lengths:
And, the second example is how to achieve that blurred background based on your position to your subject and, more importantly, your subjects distance from the background:
Again the information I presented here is simplified and basic and really ONLY the tip of the iceberg when it comes to Depth of field and creativity. I delve more thoroughly into this and many other topics in my photography workshops – so consider taking one with me; I’m extraordinarily patient, present information in a manner that everyone at all levels can understand and then integrate, and I can really help the proverbial light bulb get turned on in your head when it comes to getting the most out of your camera and equipment!
Tomorrow’s topic – the last of the week – will be on photographing at night and in low-light situations – stay tuned!
Let me know how you like the Photography Tips/Lessons so far by commenting below!
Namaste, Joanne Bartone