Bokeh

[Shoal]

I am having a problem with getting the blurred background that I want in my pics. I took some photos of my daughter the other day with an aperture of 2.8. Now some of the pictures did have the trees all blurred nicely but in others the trees were too prominent and took away from the subject. The other day I took some photos of a couple and I used an aperture of 3.5 (because there was two people and I wanted all 4 eyes in focus). However, even though they were on a bridge and the trees were about 20 feet away, the trees were just not blurred as much as they should have been, and were quite prominent. I know that bokeh is created from the distance of the subject from the background, the aperture setting, and can be affected how close you are to your subject. But does the contrast in the background affect this.... like on a bright day or a day with snow reflecting light in the trees, make less bokeh? I am just not getting the blurred backgound that I think that I should lately.... and it distracts from the subject alot. What else can I do for this?

 

[MTVision]

That's not bokeh - it's depth of field. Focal lengths plays a role as well - what lens were you using?

 

[Rephargotohp]

First off you're are (as most people do) misusing the term Bokeh. Bokeh is not the name for the out of focus area or a shallow DOF. Bokeh descrbes the quality of the Out of Focus Field soo
DOF is affected by Aperture, Distance to subject (not background That is actually a different effect) and Focal length.

So if you moved your aperture from 2.8 to 3.5 but then moved farther away from your subject... (Oopses miswrote that) Edit: You would have two things giving you a deeper DOF

 

[Rephargotohp]

That's not bokeh - it's depth of field.

Copy Cat LOL

 

[MTVision]

Copy Cat LOL

I posted first so you must be copying me!!! LOL!! The distance between the subject and background would play a role as well wouldn't it? With a smaller aperture you can still get the nice blurred background if there is a lot of distance between the subject and background. If the background is inches behind the subject then there wouldn't be as much out of focus.

 

[Rephargotohp]

Copy Cat LOL

I posted first so you must be copying me!!! LOL!! The distance between the subject and background would play a role as well wouldn't it? With a smaller aperture you can still get the nice blurred background if there is a lot of distance between the subject and background. If the background is inches behind the subject then there wouldn't be as much out of focus.

I know!!! You win! LOL

Well, yes kind of, If the background now come with in the field of focus (remembering there is only one POINT of focus and then the acceptable field of focus, but if it come with the field of focus it will appear sharper. But once it is beyond that field of focus , it's out of focus

A lot of times when people use longer lenses they think that the background is now more out of focus then when they used the same framing on a shorter lens, But that really is a matter of Perspective compression rather than any actual change in DOF

 

[mrpink]

WTB- What The Bokeh?


OP. Post examples along with the answers to the questions by other members above.






p!nK

 

[KmH]

No, neither contrast nor how bright a background is will affect depth-of-field.
Circle of confusion (CoC) is often called bokeh, and bokeh is not adjustable. CoC is a property of a lens design and how it is constructed. The number, shape, and edge finish of the lens aperture blades has a big impact on the CoC a lens produces.
The more lens aperture blades there are, the closer to a perfect circle the blades make the aperture, and the roundness of the blade edges, the 'creamier' the CoC (bokeh)

There are 2 kinds of bokeh: Cream Cheese and Hollywood.

Depth of field is a function of 4 things;
1. Lens aperture
2. Focal point to to image sensor distance.
3. Lens focal length
4. focus point to background distancee.

Here is a link to the most popular online DoF calculator: Online Depth of Field Calculator
Play with numbers in the calculator to gain a better understanding of how DoF works, and visit this. tutorial: Understanding Depth of Field in Photography

 

[rokvi]

Take a step back and zoom and set metering to point maybe...

 

[DiskoJoe]

yea, post some pics!!!!

 

[ccote321]

Maybe you're shooting with too short a focal lentgh? Try stepping back and zooming in if you can. Getting some distance from your subject is the best way to increase the bokeh effect and you can play with the aperture a bit to fine tune it. Experiment with multiple shots at different aperatures while zoomed in anywhere between 80mm and 105mm and I'm sure you'll get what your looking for.

 

[KmH]

There is no way to increase or decrease what many people call a "bokeh effect", when what is at issue is actually depth-of-field (DoF).

More specifically, a shallow DoF used to accomplish selective focus. Selective focus is used to separate a subject from the background by blurring the background.

 

[jake337]

Maybe you're shooting with too short a focal lentgh? Try stepping back and zooming in if you can. Getting some distance from your subject is the best way to increase the bokeh effect and you can play with the aperture a bit to fine tune it. Experiment with multiple shots at different aperatures while zoomed in anywhere between 80mm and 105mm and I'm sure you'll get what your looking for.

This is partially wrong. You want to use the longest focal length you have and be as CLOSE to the subject as possible while keeping them properlly framed. This is why a camera with a larger sensor/film can use a longer focal length lens and still frame a subject while being closer to them. Small camera to subject distance + longer focal length lens = shallower DOF and more background "compression).

Am right, right?

 

[brush]

This guy does a pretty good job of explaining DoF, and has awesome hair.