Photography Lesson – No 3 – Depth of Field (2)
So before I start talking about class content, I have been taught two sharp swift lessons, of which we were reminded a couple of classes ago but didn’t take heed so paid the price.
Firstly get spare memory cards. In my instance because I am saving both jpg and raw files, it takes up a lot of space and I fell short this weekend when going out to take shots for class and it became full. I wasn’t in a position to decide what to keep and not to free up space, especially in the rain and so had to return home and make do with what I had got.
The other tip is get spare batteries, I myself again went out to take some shots only to realize I had left my battery still charging in the charger, I mean seriously duh?
Various Lenses – Variable and Single Focus
In class we talked about variable focal lenses and single focus lenses. The variable type, as the name suggests gives varying focal lengths, meaning that it has more than one lens in it in order to do this. A single focal lens has just one length and as such just one lens. It is the belief that though with a variable you get more options, which is great in a varied situation, that you actually get better quality with a single focal lens. So if you are going to take one type of shot regularly, ie macro, jewellery photography etc and you know the type of lens you will most likely use then it’s a good idea to get a single focal lens that matches this.
Depth of Field
There has been a slight cross over today with last week’s class with everyone catching up and as such we are focusing again on Depth of Field. Which I don’t mind actually as I love this subject matter.
However I will try not to bore you with repeating too much.
So what is Depth of Field?
It is how much sharpness is in a picture, ie zone of sharpness. Focus determines where the sharpness is.
A rough guide is the cut off point for wide angle is approximately 24. Standard is around 35 to get what you see and after 50 it becomes telephoto. I talked about wide angle and telephoto in a previous post which you can find here:Wide Angle, Telephoto
With a Shallow Depth of Field you do not get to see much in the background as you do with Telephoto.
So we had our cameras set to A again, which is Aperture Priority.
When you change your F setting, which is the aperture size, the size of the hole changes only as you ‘take’ the shot. So you don’t get an opportunity to see it beforehand. As some asked how do you tell which is best then? The answer is, guess what? Practice, practice & practice.
Below you will see an example of how the size of the hole changes to become smaller with the higher the f/ value and vice versa with lower f/ value.
So just to go over again as I did in the previous photography post based on Aperture priority.
- Low f/ number = shallow depth of field = large hole = faster shutter speed as it allows in more light.
- High f/number = extended (large) depth of field = smaller hole = slower shutter speed as it lets in less light. This is where I come unstuck as I find I need a tripod the larger the f/value, do to shaky hands.
The f/ constraints are located on the lens which gives a to and from which depends on the zoom length at the time.
So on mine if my zoom is set to 55 = 5.6 f/value is the lowest value I can reach. Whereas with a 18 zoom it is a 3.5 minimum. My lens will there show a f constraint of 3.5-5.6
We also talked about rough ‘ideal’ fixed point lenses & f values for various things and it was said that a 24mm was a good length of landscape and No. 8 f/value is used a lot in photojournalism.
Play with aperture settings & alter zoom settings.
So here I give a few examples of two shots, the second achieving what I had hoped for or thereabouts the first indicating errors or just not giving the anticipated end result though it might look alright
1st photo, I ended up getting the focal point being the background rather than the flower as intended.
Here you can see that the f value in the first photograph is a higher number therefore giving a wider depth of field, the second photo I managed to get the focal point right in the middle giving a blur each side of the photograph.
First photograph wider depth of field, second less so and more blur going from a f value of 7 to 3.5
Again wider depth of field with a f value of 14 moving to a 4.5
This was fun trying to get the rule of thirds as well as getting the focal point in that top right corner, just about managed it!
My sons Snorlax birthday cake, he is 11 today, whoohoo so it seemed appropriate that the much cherished pokemon character should get center stage.
Just some single shots with subject matter provided by Mother Nature that I rather liked, or coveted for my own house.
Here I have a series of 4 shots, showing in various stages how the f value changes the shot though the focal length stays the same.
This was 3 seconds long because of the f/29 value. It was way too long for me to try and hold without camera shake, plus with my subject matter, namely my eldest son moving slightly this gave an extra ghostly effect!
So the f value is moving from 29 to 13, so a little clearer however in the background any movement is completely blurred and the focus on my sons face not great.
So f/13 to 5, we are there finally with what I think a passable shot!
What do you think?
Do you like using aperture priority?
If you wish to join in at all please post a link to your related content in the comments below.
If not I hope you enjoyed this memoir of my photography class.
If you wish to catch up on any of the other photography classes, please click here: Photography Classes