FG/BG Focus Question.

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DEATHTOPRINT

Active member
Okay, how do you get the type of focus, where your subject in the foreground is in clear focus, but the outer edge of them and beyond them is out of focus? and vice versa. is this achieved through certain filters?

also, if it is filters, which would be used for motion vs. someone standing still or just having a conversation?
 
Re: FG/BG Focus Question.

At first glance I thought you might be asking about DOF but now that I think about it you might be asking about filters.

Are you talkiing about when the image is 'diffused' and 'glowy' in an almost mist like state?
 
Re: FG/BG Focus Question.

After seeing a page of Barry Greens DVD and Book, I've realized im talking about Depth of Field, which now that I realize it, has probably been answered a million times on this forum.... but, if it hasnt, or if you do know some filters (if it has to do w/ filters...) off the top of your head, i'd be glad to hear some....
 
Re: FG/BG Focus Question.

Okay cool.

This is achieved 'in-camera'. Specifically DOF (Depth of Field) is:

'the distance between the nearest and furthest objects in focus as seen by a camera lens, which varies with the focal length of the lens, its f-stop setting, and wavelength of light'

It has nothing to do with Filters. If you have ever used a camera (or hopefully you have a DVX100!) and you Focus on an object in the foreground you'll notice the background becomes out of focus. It is really quite simple and rudimentary.
 
Re: FG/BG Focus Question.

the outer edge is out of focus as well?  can't say I've seen this effect.  maybe you are talking about a shallow depth of field.  If so, then sit down, take a deap breath and be prepared to do a lot of searching here on the forum.  I will not go into all the complexities of Dof, but as a photography major, it something that must be understood first before it can be used effectively.  Basically it boils down to your focal length of the lense (zoom) and your aperature.  That is really it.  There are other mythical properties that seem to appear every now and then, but that is really it.  So, the wider the zoom on your camera, the deeper the Dof.  The more zoomed in you are on your lens, the shallower Dof.  Also, the more wide open your aperature (ie. the lower the f-stop number, the shallower the Dof.  Now, one thing to remember, and this is the thing that gets everyone messed up is that Dof will always remain the same at any given f-stop and focal length.  Lets say you have a 40mm lens.  This applies to both a 35mm lens and the DVX.  AT 40mm on the lens and an f-stop of 2.8 you will have a fairly shallow Dof, eqivelent to this grab which was taken at those settings specifically.
Untitled-1.jpg

Now, 40mm on the DVX lens does not give you a very wide field of view, but 40mm on a 35mm camera lens gives you a semi wide field of view.  While on my medium format camera (6x4.5cm) a 40mm lens is a very wide filed of view.  But on all of these cameras a 40mm lens at f2.8 will have exactly the same Dof.  Here is a little diagram that I drew up to demonstrate this point.  It shows (not to scale) the difference between your DVX CCD, a 16mm sized chip and a 35mm sized chip.  
lens.jpg

now there are ways to simulate a shollower Dof when you shoot, and this something that is much more in depth than I care to explain at this time.  However, I would greatly reccomend Barry's DVX user guide which explains it quite well.  Good luck.
 
Re: FG/BG Focus Question.

Jees, when i first started my reply there weren't any posts on this topic. man am I slow or what. ;)
 
Re: FG/BG Focus Question.

Thanks a lot you guys. This place rules.

Yes, for x-mas i just got a dvx100a, and now I am figuring out how to use it. I must say, getting it was the best thing ever, and now I feel like i can die. . . happy that is.
 
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