Challenge I - Aperture and Depth of Field

[bigdazzler]

Or are you actually saying that you can choose where in the image the focus is?

yep you sure can .. This part is where your different focusing techniques come into it and play a bit of a role in how the DOF in your picture will look.

When you choose a large aperture , and create a shallow DOF, the area of sharp focus in your frame will be shallower, front to back. Thats why the body of Dans colourful animal thingy is blurred.

The head is in focus because thats the part of the subject he has focused on. If hed focused the camera further back along the body, you would see the opposite, the body would be sharp and the head blurry. Make sense ??

Your camera has three different AF ( Autofocus ) modes. Spot, Continuous, Automatic.

You will mostly use spot focus for now and thats how you can produce something like Dan has here.

Set your camera to spot focus, select a large Aperture, look through your viewfinder and you will see a small red square in the middle of the viewfinder, place that square on the part in the scene that you want to be in sharp focus, half press the shutter button until you hear a beep, this beep indicates that the camera has AFed on that point, now reframe your shot to how you want the final picture to look whilst still half pressing the shutter button down, then shoot your picture. Your result should see your focal point nice and sharp and a nice degree of blurred surrounds.

Heres an example of how your DOF can look different in your pictures by altering the point of focus within the frame,
All 3 shots were taken in Av mode, with the same aperture each time of f1.4. I did this at f1.4 because this large aperture creates a very shallow DOF to make the differences more obvious to the eye

#1. The focus point was on the front lens in the foreground, as you can see the lens is sharp and everything else is blurred from about the middle to the rear of the frame.



#2. The focus point was the lens further back in the centre of the frame. This lens is now sharp and both the foreground and the background is blurred. The aperture used is exactly the same as the first shot, only the focus point has changed.



#3. This time the focus is on the rear lens. Now the foreground and middle of the frame is blurred and the rear lens is sharp and in focus.



All three shots were taken with the same large aperture of f1.4 , only the focus point has changed from shot to shot. This demonstrates how critical it is to get your focus spot on when playing with shallow DOF and when you might want a lot of blur in a particular part of your picture ...

and PS .. apologies for the horrible white balance .. it is midnight and i just cant be bothered

[ricktas]

oh, i'm stuck!! i thought that the centre of the photo was focused on and clear and all the surroundings out of focus.... or was the photo cropped at the bottom?? Or are you actually saying that you can choose where in the image the focus is? Or does it just look that way cos the bottom of the photo is black??

Depends on your Camera Chelle. As far as I know the Sony has focus points. When you look through your lens and press the shutter button part way, do you see a red dot, square light up in the lens, (might be a different colour). That is your focus point. You should have several of these and you can select them.

Someone who uses Sony, might be able to give you a more detailed reply on what they look like and how to change your focus point.

What they enable to you to is focus on something that is not necessarily central in your lens. The other way, is to press the shutter button half way down till focus locks, hold the shutter, recompose your scene, then press the shutter button down fully. That will mean that the item you focused on originally will be in focus, but won't be in the centre of your photo.

[chelle]

oh, that is so bloody obvious now! even my old p&s let me half-click and then move to reframe the shot. Idiot! And i have been doing that with the Sony when taking happy-snaps in Auto mode but never even thought to trial it with the aperture challenge and see what happened.

Off i go to try for myself.....

[Dan AU]

Thanks bigdazzler, I thought I may have had it the wrong way around, confusing stuff sometimes.

The blurred at rear would say is more luck than anything, all I did was set it up on tripod left everything the same and changed the aperture. I think I may have had spot metering on as well for a test.

And I always shoot in manual mode to get into the habit of it, if you asked me to explain how the rear focussing has occured I wouldn't know where to start.

[mrsgrumblebum]

first image f22
I see that the pegs are all in focus as well as the back ground

second image f4.5
I can notice the difference that the pegs starty out clear and then there is a blurring effect as well as a blurry back ground

[anne-1303]

I have read through the experimenting with aperture learning centre, and have been out practicing today I am pretty pleased with the results, have definately learnt alot today, and probably more from reading through this learning centre and through the posts on this tread and practicing than I have learnt in the last year !!! I am not sure how to post my photos on here for everyone to have a look at though..... will have to learn how to do that so I can get some feedback on my pics.
Sharon

[ricktas]

Anne, do you have a website, or somewhere like Flickr, that you post your photos to. You can use those to link your photos into your posts, how to is here

If you don't, it is worth considering signing up for one of the sites in that thread. Otherwise you can post them direct with your post. Click "post reply", then type your text in the white box, scroll down and click the manage attachments button to add your photos. Note you cannot do this with the Q.reply button.

We prefer members to use the linking method shown above, as this saves on site running costs.

Hope that is easy to follow.

[marko]

Being a recent newcomer to photography, this forum is exactly what I needed.
I've been wandering the internet searching for various topics as I get stuck, but this puts all the key topics in a single location. Laid out in an easy to follow format.
Brilliant work by those involved in setting it up.


Today I found some spare time while at work to tinker with the apeture exercise.
My workplace is a little different to most, in that I'm located on the water, on a fairly unique vessel.
As such, my subjects are whatever I spot onboard that suits the given exercise.

Here are a couple of objects that caught my eye while thinking about todays readings on Apeture.

All the points about DOF, focal points and exposure length have been raised.
I found this exercise a practical opportunity to observe how the focal depth varies with apeture changes. Although I was aware of how apeture could affect this, It was never so obvious in my own shots until I made this deliberate attempt at the same shot with different settings.

This chain barrier with an apeture of f22 has no defined focal point. The whole image is clear. Useful if multiple objects exist in frame that you want to show in your photo.
Drop the apeture to f5.6 and only a single mid chainlink is in full focus. This lets the chain draw your eyes along the picture as it slowly drifts out of focus.

[ricktas]

Glad you have found what you have been seeking on Ausphotography Marko. Thanks for the feedback on the way we built our learning centre as well. Always nice to know we have succeeded.

Well done on trying the aperture challenge and gaining an insight into how aperture can help you create some truly creative shots.

[anne-1303]

Ok, here goes. I have created a flicka account and am now attempting to link my photos to here for everyone to see. I hope I am doing this right...... Hope I have resized these right so they are the right size required on here?? If I have done something wrong could someone please let me know At least I have got them appearing on here !!!

[chelle]

hey marko, i think i am going to like looking at some of your photos.
Usually i have been preferring the photos when there is a much smaller focus area but your second set of images just shows how sometimes the photo can be much more effective with the larger f setting. thanks.

[ricktas]

Good work Anne, now from your challenge photos, have you gained an understanding of how aperture can affect the result?

[Jcas]

I am enjoying seeing peoples creativeness with this thread, some of the examples used are great, the clothes pegs, the chains, the fluffy toys, the lenses and the list goes on

Well done all.

[learn2shoot]

what a fantastic challenge. I think this is great way to get the info to "sink in". I will have a go and upload some pics and findings.

[Hobberz]

I am a bit late but thought i would give it a go.

F/22- Subject and backround are in focus, also it is a little over exposed.

F/4- Backround is not in focus


F/22



F/4



Great Exercise

[bigdazzler]

spot on Hobz .. you can see how shallow the DOF is at f4 .. even the rear of the tap is out of focus. If you stop down another 1/3rd or 2/3rd's of a stop to 4.5 or 5 , you should get the entire tap in focus and the wall will remain burred.

[anne-1303]

Hi Rick, yes I have gained a great understanding of how aperature affects the depth of focus now - something I never understood before!! I have been practicing some more this afternoon, and have no problems with things close up but am having a little trouble getting the background blurred of things abit further away??? Why is this???? Not sure what I am doing wrong here. I tried to take a couple photos of my daughter standing outside, but couldnt' get the background nicely blurred behind her?

[ricktas]

As you get further away from your subject, the DOF increases, so to get the background blurred you need to ensure your daughter is further away from the background.

[Becstarr]

I just tried to upload some pics but was unable to do so , I just went into reply to thread and then pressed the paperclip to add attachments where did I go wrong

[ricktas]

how big are are your files Becc, they have to be under 1024 pixels on the longest side and under 200KB?