Help With Bokeh

[Buszaj]

Hey everyone,

I need some help on creating a blurry background when shooting sports. I shoot in full manual, and usually have the aperture between 2.8 and 3.7. I hear that a low aperture number is needed for this effect. Yet, I still can't get the background to be blurred. (I'm zoomed in to the max most of the time).

Thanks

 

[Patrice]

For any given aperture, the DOF increases as the distance to your focus point increases. So the farther away your subject is the deeper the DOF. If you can try and have your subject at the far end of your DOF with most of the area of aceptable focus in frnt of the subject. This is easier said than done with fast moving subjects. Try to anticipate the action and shoot to it.

 

[Garbz]

The problem is that sensor size is also a variable. f/2.8 on film and even on APS sensors would give a VERY narrow depth of field. On a smaller sensor camera like the Lumix DMC-FZ3 I am not sure if you can do this well.

 

[kundalini]

Here's a good read on exposure that explains aperture, shutter speed and ISO. Understanding Exposure. One thing I remember from the book is to have you subject 5-10 feet (1.5-3M) away from the background for a good bokeh.

 

[Sw1tchFX]

Hey everyone,

I need some help on creating a blurry background when shooting sports. I shoot in full manual, and usually have the aperture between 2.8 and 3.7. I hear that a low aperture number is needed for this effect. Yet, I still can't get the background to be blurred. (I'm zoomed in to the max most of the time).

Thanks

You need to consider, what's the real focal length of your lens, not the equivalent? Depth of field shortens with a longer focal length. If your lens' at it's longest setting is 35mm, than you're not going to have the DOF that a 400mm has, even though it may seem to be framed the same.

 

[ThePup]

As has been mentioned, your problem is that you're using a Point n shoot camera, with a very small sensor (1/3.2" - 4.5 x 3.2mm). The smaller sensor and lenses means a smaller equivelant aperture. 2.8 on your camera is much smaller than 2.8 on a DSLR.

The only way to get a shallow DOF with the sort of shots you're after is with a decent size sensor from a DSLR I'm afraid. My old Canon A95 has a larger sensor than the panasonic, and it's not capable of blurring the background either. Very frustrating when trying to get nice portraits of the kids.

Choices - Buy a DSLR or Learn to use photoshop / GIMP. (It's not actually too hard to blur the background in post processing, do some googling and practice...)

 

[Greatwhite]

What is Bokeh?

 

[ann]

It is the term used to describe the wonderful smooth out of focus backgrounds

 

[Jestev]

Ya, you may have some problems with bokeh if the subject isn't like right next to the camera even at the largest aperture.

 

[Buszaj]

Thanks for the answers. The SLR will have to wait till July, I'm planning on getting one then before my trip to Kenya.

 

[fmw]

You need to consider, what's the real focal length of your lens, not the equivalent? Depth of field shortens with a longer focal length. If your lens' at it's longest setting is 35mm, than you're not going to have the DOF that a 400mm has, even though it may seem to be framed the same.

No, the behavior of a lens relative to depth of field is the focal length. That is printed on the lens. "Equivalent" has no meaning in this sense. Depth of field varies with subject distance, focal length and aperture. Nothing else.

 

[XJBaylor]

Thanks for the answers. The SLR will have to wait till July, I'm planning on getting one then before my trip to Kenya.

Make sure you give yourself a few months to get used to the camera. That way you can get the most out of it on your trip.

Keith

 

[JerryPH]

The trick for a nice creamy out of focus shot is a combination of things...

- wide open aperture... 2.8 or numerically smaller is the first key.

- the ratio of the distance from lens to what you are focusing on has to be less than the distance from the focusing point to an area behind it, so that it can blurred

Something like this as an example:

The greater the ratio between front and back, at a wide open aperture of f/2.8 or less, the greater the blurring effect, we know as bokeh, occurs.

The inverse of this is a completely focused picture no matter where you look. This is the result of a closed or numerically higher aperture.

You may hear about something called HyperFocal focus and is used mostly for wide deep pictures like landscapes... this is where the F-stop and lens are adjusted so that almost no matter what picture you take, it is 100% focused from very near the camera, to infinity.

 

[Helen B]

...Depth of field varies with subject distance, focal length and aperture. Nothing else.

Well, apart from the diameter of the acceptable circle-of-confusion - which is related to the magnification from the sensor/film size to the final image size for viewing (eg the print size). This should be taken into account when comparing DoF between formats.

Best,
Helen

 

[fmw]

Well, apart from the diameter of the acceptable circle-of-confusion - which is related to the magnification from the sensor/film size to the final image size for viewing (eg the print size). This should be taken into account when comparing DoF between formats.

Best,
Helen

No, Helen. It doesn't. The image size or amount of enlargment has no effect at all on depth of field. It affects grain/noise and composition. Not depth of field. Again, focal length, subject distance and aperture control depth of field. Nothing else.