India Broadband Forum

Preeti_20

I have seen a few images on the net, where the closer image is really clear and the background is very slightly blurred and it makes the main image of the photo stand out.

How is this done or what software is used for this?

Is this something which can be done using photo shop too?

Punch Farce

It is called depth of field. These days with the advent of
digital cameras the photography concepts are not learnt as before.
people just point and shoot and load mostly crappy pictures into the net
You can do it in photoshop but you can tell it was photoshopped.

The way to do this is manual control of your focus and depth of field

depth of field is the range if distances that are in clear focus, anything
in front of this or behind this becomes progressively out of focus and
looks blurred. This is used as you said to make the main subject pop out.

There are three things that affect the depth of field
1. the aperture used (wider aperture means less dof)
2. the distance from the camera to the subject (closer means less dof)
3. the focal length of the lens used (longer telephoto have smaller dof)


so if you want a shallow depth of field (to make the subject pop out)

you can use a longer telephoto lens (90mm and above in 35mm terms)
you can use a larger aperture and faster shutter speed (f2 to f4.5)
you can move closer to the subject.

Hope this makes sense, if you have questions please ask.
I am a photography/camera nut ;-)

-F

Preeti_20

Farce I didn't get a thing you just wrote Well i kind of have, but not the way it should be understood, i mean its too big talk for me!

I dont have those posh and expensive lens cameras, just a basic Canon 7mp camera.

Punch Farce

Ok, the camera doesn't have to be expensive, does your camera
have manual settings? I mean can you set the shutter speed or aperture?
there are different modes usually program, simple, night, action etc. Is there
a manual mode on the camera? or something called Aperture priority?

-F

Punch Farce

For example this is a camera I have



If you see the circle I marked is the setting for manual focus
and the line points to the ring you turn to focus.

Now this is the top view of my camera


See those two circles those are the two modes that lets you
choose the aperture. M and A modes.

Now put it in A mode. go to the menu and set the aperture
to the lowest value possible. This camera has a nice bright
Leica lens that is f2. but most digital cameras these days
start at 3 or 4 and go to 16 or 22. Just choose f3 of f4.

then shoot the picture. set it to f22 and see the difference.

-F

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meetdilip

@ Preeti

Take photo from any camera and use the blur option in Picasa. It is simple enough for beginners.

Preeti_20

@ Farce - I dont have that feature on my camera at all, just the functions which can be changed according to the place you are at, such as outdoor, indoor, landscape and so on!

@ Meetdilip - I think i know what your talking about, it blurs the image, and you can focus on a particular part in the photo, but this does not give the same affect, as the the part which is highlighted comes as in a form of a circle.

Here is an example of how i want the image to be:

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	istock_generic_7271.jpg (19.4 KB, 33 views)

panchabhut

sorry. you can not get this effect on any autofocus camera.

Preeti_20

I cant get it on mine, i have the Canon powershot A550, unless i dont know about this feature which i may have, as i never read the booklet!

just4kix

Preeti,

I have done the above effect hundreds of times. It is late now. Tomorrow I will scan and post some pictures.

First all all, it has nothing to do whether it is an autofocus or manual focus camera. It can be done with any camera that gives the user the control over the aperture.

Farce has explained the phenomenon correctly. It is known as "depth of field". In layman's terms, depth of field means the the minimum and maximum distance from the lens where the objects are in focus. The following wiki figure explains:



As you can see from the above picture, objects that are too close or too far are not in focus.

The depth of field is controlled by the lens aperture. The larger the aperture the lesser is the depth.

The lens focal length also controls the field depth. Long focal length lenses (telephoto lenses) have much smaller depth of field and vice versa.

So to accentuate a subject against a blurry background, do the following:

• on a zoom lens, choose to close (zoom) in on a person from a slight distance
• switch the camera to aperture priority mode (if supported) or choose a shutter speed such that aperture is maximum

The current breed of compact P&S digital cameras are not not really geared for such things although it is possible to do so. An SLR gives much more control in such cases.

Read the article: Depth of field - Wikipedia, the free encyclopedia

__________________

Preeti_20

Thanks J4K, will wait for your pictures tomorrow and hope to learn some tack ticks from you and how to get these kind of effects! Thanks

Punch Farce

If you don't have manual settings, try the portrait mode or night mode,
those should have programmed to have large apertures and relatively
shallow depth of field.

-F

just4kix

Here are the pictures as promised:


Picture 1: Bulb fields, Keukenhof, Netherlands

The above shows huge depth of field. Almost everything is in focus - from near to the lens to infinity. This shot was take by Nikon N70 film camera, using Tamron 28-100 f/2.8~4 mm zoom lens, set at 28 mm. Snapped at 1/250 s @ f/8 aperture.

Short focal length (28 mm) in the above case allows a wide angle of view. The narrow aperture (f/8) ensures high depth of field.


Picture 2: Purple Lillies, Keukenhof, Netherlands

In the above picture, the depth of field is shallower. Picture was taken by Nikon N70 using Nikon 70-300mm EX lens, set at approximately 135 mm and snapped at 1/125 s, f/4 using a tripod.

The long focal length (135 mm), and wide aperture (f/4) make the depth of field much lesser.


Picture 3: Classic Red Tulip, Keukenhof, Netherlands

This picture enhances the image by reducing the depth of field to almost 1 foot. The picture was taken by Nikon N70, using Nikon 70-300 mm lens, set at approximately 300 mm and snapped at 1/250 s, f/5.6 using a tripod.

---------------------------------------------

Digital P&S cameras do not provide many such creative controls that easily. Farce is correct. Switch the camera to Portrait mode.

panchabhut

no pictures J4K

newprouser

I can see it...

Preeti_20

OK J4K, can you help me with this, so this is called depth of field. SO can this be done with any camera, and the blurred background can that affect be done using a photo software?

Preeti_20

answer someone please, especially J4K!!!!!!!!!!!!! I have a basic Canon Powershot camera!