Help needed

I started my photography class tonight and am not feeling very confident about things.

I'm in the Improvers class and am actually wondering if I should be

I was told that the beginners class was from how to switch on your camera , how to press the button to how to download your picture - all of this I thought I knew , wasn't able to talk with the Tutor , so thought that the Improvers class was for me

We seem to be a mixed bunch - should be 14 of us , mixture of Canons , a Fuji [ bridge I think 'cos it looked like my S5000Zoom ] , a P&S , but the owner had a bigger camera as well . Sadly there are PCs for editing and he insists we use them - Adobe CS2 and Bridge is the software.

He started off by firing questions about Aperture and what shutter speed would you use for which Aperture settings . OK - I listened and learnt some and hopefully absorbed more.

He then drew a camera on the board - well a series of boxes Asked us where the Aperture was , where the lens would be , etc - I was OK with this - actually surprised myself when I knew what an SLR was [ explained the Reflex bit ] Even remembered from waaaaaaaay back that the image was reversed in the camera

We have been set homework for next week and this is where I need help - in very simple terms please .

We are to take in , on camera for downloading or on a Flash drive a photo taken with an Aperture of 2.8 and a shallow field - and this is what I don't really understand .

As he explained it the field is the bit in the same plane as the subject so if you think of a wee stick man as the subject then you have a very small amount round him thats in sharp focus , but this decreases as the distance from subject to camera increases ~ I think ~ .

Please would someone have a shot at putting this into very simple terms for me .

I'm putting the camera into Aperture Priority for this week.

OK, if you set a wide aperture (small number such as f2.8, f4, etc.) and focus on something then very little in front and behind the subject will be sharp. This is shallow depth of field.

If you set a small aperture (big number such as f11, f16, etc.) then much more will be in focus in front of and behind the subject. This is increasing your depth of field.

Example of wide aperture: A close portrait with the background out of focus emphasises the subject.

Example of maximising depth of field: A landscape with everything sharp from very close right to the horizon.

Hope that helps without complicating matters too much!

Depth of field relates to how much of an image is in focus, and it's a lot simpler to deal with on older manual lenses as they usually have a depth of field scale. Basically at f2.8 things slightly in front of or behind your subject will be out of focus. As you stop down the depth of field increases, so items around your subject become less blurry.

For example, if I'm photographing birds on a feeder with a telephoto lens I may want shallow depth of field to render the greenery behind a blur, making it less distracting and a pleasing background to the birds. The wider aperture will also allow me to use a faster shutter speed, handy when dealing with nervous wildlife. However, if I'm photographing a model truck in macro then I will want a deeper depth of field in order to have as much as possible of the subject in focus rather than a pin-sharp windscreen with a blurry bonnet.

This link may help: http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

He means a shallow "depth of field".
The depth of field generally increases as the subject to camera distance increases. ( and vice versa)
The depth of field is the range of distances from the lens that are in focus. Say for example everything between ten and fifteen feet( or metres if you prefer) from the lens looked to be in focus then the depth of field would be 5 feet. ( the distance between the nearest point in focus and the farthest.)
Say your stick man was a goalkeeper stood on the goal line and you were on the penalty spot with your camera. If you focus on the goal keeper then everything on the goal line will be in focus too. At wide apertures like 2.8 the depth of field will be quite shallow. so if your goal keeper took a step forwards he would start to become out of focus, and equally if he took a step backwards, as you are still focused on the goal line. At smaller apertures like f8 or f16, the goal keeper would have to take three or four steps forwards or back from the goal line before he started to be out of focus, as smaller apertures give a greater depth of field, ( or a greater range of distances from the lens where everything remains in focus)
If you move back to the half way line now and focus on your goal keeper on the goal line, the lens will probably have to be focused on it's infinity focus limit. Now even at f2.8 the goal keeper can move back as much as he likes and he'll still stay in focus,this means you now have a huge depth of field when the lens is at infinity. But if you move right up close to the goal line the goal keper will only have to sway a little bit back or forwards before he goes out of focus.
Does that make it any clearer or have I confused you more?

Damn I wish I'd typed faster!!!

If you want some pictures with it.
link
link
link

Like said just look at the pictures with what you read here in the other comments, if you want to learn more you can read the articles but they go a bit deeper into the matter.

This might help.

Why do men always illustrate things by football ?

This is exactly what Jeff was doing tonight and we had the action re-plays too to show us the hand positions as the goalie leapt for the ball .

The first two replies - JohnRiley and Matt were making sense , I've still not looked at Graham's link - will leave that for tomorrow .

MarkD - are you sure your name's not Jeff ?
That's been a wonderful memory jog - thanks .

Now to go and find a subject aaaargh and I can't start on this until probably Thursday .

We were warned - next weeks topics are White balance and ISO - wonder how they will get linked to Football


Guys - you are brilliant - thank you sooooooo much .

One of these days I'll get my courage up and shove a pic or two on the board for you all to tear to shreds .

The best way to see the effect of the shallow depth of field and to learn this is to take a series of shots, but to do this you'll need a tripod or something to keep the camera steady, so putting it on a table would be fine for this if you don't have a tripod.

Set the camera to aperture priority and select a wide aperture F2.8 (or as wide as your lens will permit if it will not go to F2.8 and judging by the lenses on your post they may not be F2.8, probably f3.5 on the 18-55) manually focus on object and take a photo.

Then change only the aperture to f11 and take another and keep going up the highest f number of your lens. Review the images and you will see more of the background behind the object you focused on coming into focus.

I think you are doing the right thing by learning, but you need to experiment. I spent a year on 'green' mode and I wished I'd learnt more earlier!

I hope this helps, good luck and keep us up to date with how your course is going!

Angela,

Simonarthurs idea is a very good one, you'll quickly see the difference. One thing I would add, though, is that you must keep the focal length the same. So I suggest you take shots of the same scene, a portrait or a still life would be ideal, fully zoomed in at 55mm on your 18-55 at f3.5, f8 and f16.

Wide angle lenses have greater DoF than telephotos so the effect will be more pronounced at 55mm than 18mm.

Hi Angela,

Just following on from Ken and Simonarthurs posts, note that the maximum aperture on the 18-55mm lens when zoomed in to 55mm is f5.6. The f3.5 aperture is only available when zoomed out to 18mm. If you can, try setting up your camera at an angle to a sheet of newspaper. Focus on a line of newsprint in the centre of the sheet and you will very clearly see the depth of field in front of, and behind, the line you focussed on. You will see more lines of print in focus as you change the aperture to a higher number - f11, f16 etc. Good luck with your course. If necessary you can always bribe teacher with some sweeties!

Cheers
Chris

Of course you can also take the 50-200 at the long end(200mm),
focus at a subject close by at the widest F stop )f5,6 and pull the DOF preview lever to see the effect real-time in the VF. Now repeat this exercise with the aperture closed to F 22, to notice the difference in DOF.
That why Pentax provided the K-X with one, right?

I would take three film canisters or candles glasses etc etc place then in a row diagnally accross the frame, and shoot 1 shot with the middle object sharp wide open the second shot with the first and second object in focus at middle aperture, and third shot with all three objects in focus with the aperture stopped right down.

carefully space out your objects and it is easy to do..
tripod mounted camera at table level, first object approximately 1/3 the way between the objects, objects about 1 meter from front to back and framed equally apart in viewfinder..

use a fifty mm

Martin, it wasn't on the K-M it is on the higher models though like the K10D, K20D and the K7 don't know about the others.

They do have a digital preview if I'm correct.