Simulated Depth of Field

[barrydoig]

I attach a rodeo photo I recently took. I wanted to simulate the depth of field effect of a reasonable lens, putting the background out of focus but the foreground still in focus. My method was to select the guy and the bull, and use a gaussian blur to put the background out of focus but keep the guy & the bull in focus. I then used the eraser tool to bring the foreground sharp again, gradually reducing the opacity as I moved the tool across in broad strokes and moving up the picure. The end result should be a graduated depth of field effect. But it's not right. The background blur is too abrupt. Is there a way to use a gradient to give me that graduated depth of field that I'm looking for? I would be interested in some comments. I'm using Elements 6 Thanks, Barry

[Colin Southern]

Hi Barry,

For what it's worth, I've never had much luck doing this either; I'm wondering if part of the problem is that a gaussian blur doesn't emulate lens bokeh particularly well.

Possibly easier to just install a ND filter on an existing lens, and shoot wider?

Additionally, I am aware of the existence of plugins that supposedly simulate a tighter DoF during post-processing, although I've never used them. In Photoshop I'd probably select bull & rider - select the inverse - copy to seperate layer - apply gaussian blur (or perhaps some other filter/effect?) the use varying shades of gray on a layer mask to conceal / reveal appropriate amounts of each layer.

The following Adobe help documents might be of interest also ...

http://livedocs.adobe.com/en_US/Phot...DD602CA63.html


http://www.adobe.com/designcenter/ph...plensblur.html

Hope this helps,

[Pawel]

Why do you guys use guassian blur when there's lens blur right next to it?! Gaussian blur is completely different and cannot emulate shallow depth of field. Lens blur is much better at this and produce more natural look!

[arith]

I've only ever thought of doing this but now can see the problems with it. Firstly the outside edges of the lens would have less resolution but also some of the foreground. A radial gradient on a selection mask on its own will not be good enough but the mask would also need to be touched up with a linear gradient. I suspect it is possible but don't know how to do it, blending selection masks is not something I've done.

[rick55]

Why do you guys use guassian blur when there's lens blur right next to it?! Gaussian blur is completely different and cannot emulate shallow depth of field. Lens blur is much better at this and produce more natural look!

Elements (at least PSE6 and PSE8) doesn't have lens blur in the filter menu, at least in the versions I have (US, both direct from Adobe). Maybe there are plug-ins available.

Cheers,
Rick

[arith]

Just to give an idea what I mean and to discover how hard it is to do. This is an image sharp throughout and using Gimp I created a duplicate layer ( maybe there is a way to create just another layer but this is the way I did it) and filled it with black. Using a black to white gradient I then placed a radial gradient bang in the middle. Created another layer this time on multiply and applied a white black white linear gradient, messing around with opacity to sort of get what I want merged the top onto the middle and then copied it to the clipboard. Delete the layer and bring up the selection mask and paste into it. Then use gaussian blur on the selection.

It is hard and a lot of work, here quickly done I've discovered it isn't really something I would like to perfect.

[arith]

Well I didn't think that out but here is another try but this time making the top layer addition, I could possibly have chosen a better picture but all mine with a single subject are already dof I think.

[arith]

Is this one close, I think it is close.

[barrydoig]

Thank you to those who replied to my query about simulated depth of field. I agree John that gaussian blur doesn't emulate lens bokeh very well. I am using Elements 6 which doesn't have the Lens Blur filter even if it does work. I downloaded a gradient blur plug-in which has proved useless. Steve your trees image is close to what I want and I'd like to know how you did it. Meanwhile I tried using a black to white gradient adjustment layer. Having first selected the foreground area I wanted - the horse and rider- I deselected it and applied the gradient to a levels adjustment layer and gave it a gaussian blur. I then reselected the hors & rider used the eraser tool to wipe away the blur and reveal the sharp Background underneath. The result is not too bad and I think an advance on my previous image.

[RobO]

I attach a rodeo photo I recently took. I wanted to simulate the depth of field effect of a reasonable lens, putting the background out of focus but the foreground still in focus. My method was to select the guy and the bull, and use a gaussian blur to put the background out of focus but keep the guy & the bull in focus. I then used the eraser tool to bring the foreground sharp again, gradually reducing the opacity as I moved the tool across in broad strokes and moving up the picure. The end result should be a graduated depth of field effect. But it's not right. The background blur is too abrupt. Is there a way to use a gradient to give me that graduated depth of field that I'm looking for? I would be interested in some comments. I'm using Elements 6 Thanks, Barry

I have found this http://www.ononesoftware.com/detail.php?prodLine_id=8 to be amazing software and works hand in hand with Photoshop. Focal Point is the package within the suite which you will require. The only down side I have found is that when they upgrade the software it's a "major" download - just short of 2Gb ! [I only have slow BB ] - As you will see - you can try before you buy and they occasionally have special offers too.
RobO

[Dave Humphries]

~ The result is not too bad and I think an advance on my previous image.

Hi Barry,

Yes, it is an improvement, I think if you study it and have another couple of attempts at it, you'll be getting quite good at it.

I think I am just saying practice makes perfect.
For me, this attempt has lost a bit too much focus and contrast in the background.

Better though,

[arith]

I think it is quite good.

Before I read this I didn't think a computer could simulate dof, but often thought about it because what could be nicer to a landscape photographer to just choose the hyperfocal distance then choose out of focus in the computer.

It takes three layers to simulate dof above the background. A linear gradient layer, a radial gradient layer, and one that picks out those objects in the foreground but not in the centre of the image.

These are merged as additive layers (opacity dependent on what is required), and because I don't know how to do it and it is easier I just copy these and paste into a selection mask. Then straightforward ordinary Gaussian blur is applied.

Cheers.

[barrydoig]

I have found this http://www.ononesoftware.com/detail.php?prodLine_id=8 to be amazing software and works hand in hand with Photoshop. Focal Point is the package within the suite which you will require. The only down side I have found is that when they upgrade the software it's a "major" download - just short of 2Gb ! [I only have slow BB ] - As you will see - you can try before you buy and they occasionally have special offers too.
RobO

[arith]

Looks great but I haven't got photoshop CS3 or 4, and I have only 2GB of ram of which 1GB is used. Then 2GB download would take me two hours to download. But it looks the business. cheers