Photoshop 7--DOF

[katzsteel]

I've started taking a lot of photo's using my little Canon G2. The only complaint, very limited depth of field. Is there an easy step by step process to blur the background in Photoshop? I've tried several methods and none seem to work that great for me. Does anyone have a step by step procedure blurring the background? I know it can be done, but I have not found a good resource as of yet. Thanks for the help in advance.

[Trevor Ash]

I've never really done much of this myself and haven't seen any filters that do it either. I imagine GOOD filters would be hard to create.

I've tried several methods and none seem to work that great for me

What didn't you like about the results you received? Maybe the techniques are good but you just need more practice. Or maybe your subject matter is a very complex one.

Personally, here's how I'd go about doing things.

1. Determine what are foreground, mid, and rear elements by thinking of the photo as three dimensional.
2. Create masks for each element of this third dimension. So, one mast for my uncle larry and his big fish he just caught, another mask for the large fishing boat behind him. And yet another mask for everything else in the background.
3. Using the masks to apply my selectice blurring, I would blur the background boats and the boat directly behind uncle larry with different amounts of blur. I'd make sure the things further in the background had more blur than things closer to the camera.
4. Then I'd go any look for highlights and reflections that look like they would produce strong bokeh in normal circumstances and try to replicate this effect digitally (hoenestly, I'm not sure how I'd replicate it).

Is this pretty much how you did it? Let me know what you tried and perhaps post your before and after results (even if you're not happy with it). I may be able to offer a few tips to improve whatever technique you're trying.

Cheers and good luck.

[Asylum Steve]

I think you need to clarify a couple of things. I get the question about ps, but not the comments about your camera.

You say the G2 has "very limited DOF". DOF is not a facet of an individual camera, but rather what f/stop your aperture is set to. So, ANY camera can give you both large and shallow DOF.

Second, VERY LIMITED DOF would mean your bg is most likely out of focus. Isn't this what you want? My point is, if your shots already have a very limited DOF, there should be no need to do anything with it in ps. Maybe you're confusing your terms...

Anyway, dealing with the second part, Trevor's advice is good, although a bit tricky. If you have a clear foreground foreground subject/bg relationship, getting the effect you want might be as simple as feather selecting the subject, putting it on a seperate layer, then playing with the blur tools on the bg.

If you really want to get serious about quality selective bg blurring, I'd either get Andromeda's Varifocus filter, or for about the same amount of money upgrade to photoshop CS, which now has an excellent PHOTO BLUR filter that does exactly what you trying to do. Plus, you'd get all the other great new features included in the upgrade.

I've started taking a lot of photo's using my little Canon G2. The only complaint, very limited depth of field. Is there an easy step by step process to blur the background in Photoshop? I've tried several methods and none seem to work that great for me. Does anyone have a step by step procedure blurring the background? I know it can be done, but I have not found a good resource as of yet. Thanks for the help in advance.

[Trevor Ash]

Yo Steve, how's it hangin?

DOF is not a facet of an individual camera, but rather what f/stop your aperture is set to.

Believe it or not, this isn't true! It's true if you're about camera's with the same sensor size and lens but when comparing the G2 to something like the 10D it's no longer true (all camera settings and subject being equal).

So, ANY camera can give you both large and shallow DOF.

This part is true, but the DOF of the G2 cannot be made as narrow as that of the 10D using an EOS lens with the same aperture and effective focal length. Part of this has to do with the extremely wide angle lenses used on these small point and shoots combined by the very high multiplication factor (crop factor, whatever) of the sensor. So even though it's equivalent to "35mm" the lens on the G2 is really at something more like "7.2mm". Using an aperture of f/2 the aperture hole ends of being 7.2/2 instead of 35/2. That's quite a difference in ratios and thus DOF.

I realize you know this stuff Steve, but for others that don't there are three things I know of that affect DOF; Focal length, aperture, and subject distance (where you're focused). I hope someone will let me know if I've forgotten any!!! It's been a while since I've studied this stuff

Second, VERY LIMITED DOF would mean your bg is most likely out of focus. Isn't this what you want?

I think by "limited" he meant that DOF is very WIDE and the ability to make it narrow is "limited".

I really like the rest of your advice and suggestions, I'll have to remember those too.

[Asylum Steve]

Well, I was right AND wrong at the same time. Funny when that happens.

So bittersweet...

I figured Mark used "limited" the wrong way, I just wanted to make sure. But, really I didn't know about the DOF "problems" with the small sensor digicams. The way you explained it makes pefect sense. I put "problems" in quotes because most consumers probably want everything in focus, and don't consider it a liability.

Us creative types know better...

Yo Steve, how's it hangin?



Believe it or not, this isn't true! It's true if you're about camera's with the same sensor size and lens but when comparing the G2 to something like the 10D it's no longer true (all camera settings and subject being equal).



This part is true, but the DOF of the G2 cannot be made as narrow as that of the 10D using an EOS lens with the same aperture and effective focal length. Part of this has to do with the extremely wide angle lenses used on these small point and shoots combined by the very high multiplication factor (crop factor, whatever) of the sensor. So even though it's equivalent to "35mm" the lens on the G2 is really at something more like "7.2mm". Using an aperture of f/2 the aperture hole ends of being 7.2/2 instead of 35/2. That's quite a difference in ratios and thus DOF.

I realize you know this stuff Steve, but for others that don't there are three things I know of that affect DOF; Focal length, aperture, and subject distance (where you're focused). I hope someone will let me know if I've forgotten any!!! It's been a while since I've studied this stuff



I think by "limited" he meant that DOF is very WIDE and the ability to make it narrow is "limited".

I really like the rest of your advice and suggestions, I'll have to remember those too.