How to get nice bokeh/blur with an F4 zoom lens?

skywalkerbeth · Apr 4, 2008

Hi!

I have a new Canon 24-105 F4L lens.

I know F4 isn't going to have super blur. How do I work around that?

Should I set the aperture on F4, move back from the subject while zooming in? Or what method would work best? thanks...

JerryPH · Apr 4, 2008

For bokeh to happen the easy way:
- set your aperture to the lowest numerical number your lens has.
- either zoom in close or stand close to your subject.
- you have to have lots of room BEHIND your subject.

Bokeh relies on 2 things basically:

- Aperture (as mentioned)
- The ratio of distance between your camera and subject VERSUS the ratio of distance from camera to area beyond the picture where you are focused on.
- If the distances do not change, you increase bokeh by opening up the shutter (moving aperture to a smaller numerical value).

The trick is that you need more visible room behind the target than is the distance between you and the target... and voila, bokeh appears.

Do you absolutely need F/4 or faster to get bokeh? Nope. I got some good bokeh here at apertures as high as F/7.
Note the background (and the man in the foreground as well!):

Mav · Apr 4, 2008

Get as close to your subject as possible, and if you can try to make sure the background is as far away as possible, and use the longest focal length you can. I can get nice background blur with f/5.6 lenses this way. The 24-105 f/4L is a really nice lens!

This is one of the lenses I lust over as a Nikon shooter. Nikon just doesn't believe in f4 glass. :grumpy:

skywalkerbeth · Apr 4, 2008

thank you!

OK, so let's say I'm trying to get a great shot of my brother and sis-in-law in front of the cherry blossoms with the 24-105 F4.

It sounds like I want to have them stand FARTHER away from these trees... and use my zoom to zoom in on them (how close should I stand to them - since it's a long zoom? or just don't use as much zoom and stand closer?) and set it on F4?

Big Mike · Apr 4, 2008

It sounds like I want to have them stand FARTHER away from these trees... and use my zoom to zoom in on them

If you want then trees to be out of focus...then yes.

how close should I stand to them - since it's a long zoom? or just don't use as much zoom and stand closer?)

You get a shallower DOF by using a longer focal length, but your background will be farther out of the DOF, the closer you are to your subject. So it's sort of a trade off. I'd go with the longer focal length and stand where you can frame your shot the way you want.