Help!

[Anna Elise]

Hi All

A newbie here in need of some advice and/or tips. I'm currently doing an assignment for my photography course and I'm stuck

Basically, I need to take a picture of a person or similar sized subject with a 'varied' background with my camera in AV mode starting with widest aperture and stopping down to smallest aperture and talk about the differences in the pictures as the aperture changes. I understand that by making the aperture smaller (larger f number) that the DOF will become shallower and the background more blurred as the aperture becomes smaller. However, putting this into practice is not giving me the expected results My problem been that all the pics I took, each at a larger F number, look exactly the same?! No change in the background at all?!

Anyone, got any ideas about what I could be doing wrong? Suggestions on how I could get the desired result? I have read many articles, tutorials, etc and, whilst no expert by any stretch of the imagination, I understand enough to know what should be happening but it just isn't!!

Hoping to be pointed in the right direction

Anna Elise

 

[dfrear]

You won't really notice any difference if the changes are small, but if you increase a few stops each time you should notice a difference. Start at something like f/1.8 and stop down a few each time instead of just one.

 

[dod]

Any examples? First reaction is it's the distances between the camera and the subject and the subject and the background which are the issue here.

Also, you've got the delationship between small aperture and DOF round the wrong way It's large aperture (small number) which reduces DOF

 

[HoppyUK]

As dod says, it sounds like a distance issue. If you're focused on a distant subject, then even though depth of field is changing with the aperture, you'll not see it much. If you're focused on infinity, you will not see it at all.

To really see depth of field at work, you need a close subject and a wide aperture (low f/number). If you're using a compact it will be harder as the small image format naturally delivers much deeper depth of field than an SLR.

 

[arclight]

It may help if you pick a subject with a line receding into the distance (eg a fence with posts every couple of metres) so that the parts that are in and out of focus will show up clearly.

 

[fletch5]

take a friend and a 50mm 1.8, stand in the middle of a road and take a shot at 1.8(make sure you focus on the eyes) and a shot at f12. you should see a massive difference