GH2 No DOF?

Craigsnedeker

Craigsnedeker

Active member
I took some pictures of myself today with an f-stop of 4 (the lowest I could get) with a ND4 filter, and there's no DOF from what I can see. Any idea what I am doing wrong? I was in Aperture (A) mode.

E8ISw.jpg


Thanks
 
what lens?

For a shot like that you need a telephoto lens... 85mm and above and u need to have the camera reasonable far from the subject at F2.8 and below. With an even longer lens you dont even need the iris to be that open. And to be technically correct...the shot as deep DOF. So yes it does have DOF just not shallow DOF as you would like :)
 
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You can clearly see blur beginning around the first section of road directly behind the truck. DoF has many variables including distance to subject, focal length and of course f stop.
 
As someone above mentioned, Depth Of Field has variable factors that apply.

Yes, if you moved the camera closer that would help but what is working against you (for shallow DOF) is the focal length you are using. With short focal lengths (wide angle and wide angle zone of a lens like that 14-140) the way spatial relationships are rendered tend to make it look like you have fairly "deep" DOF.

For what you want get the lens to the 50+ (out to 100 or so, but 50 should work), move the camera in fairly close to compose the head and shoulders aspect you want and you should see a shallower zone of accptable sharpness at about f4 (I've seen it done at f5.6).

The factors that apply:

Lens focal length (wide gives apparent deep DOF, long makes it shallower)

Distance from camera to subject (closer makes zone shallower, farther makes the zone deeper)

Distance from subject to background elements (more distance makes background go more out of focus, less distance does just the opposite.

Hope this helps.
 
Ok, thanks a lot!

I'm also trying to get deep DOF with wide angle lens (I've seen it done) though I'm thinking I just need a special lens for that, kit lens can't provide that. Is this correct?

I ordered an adapter to use some 2.8 Pentax lens, any idea if they will work?
 
Craigsnedeker said:
Ok, thanks a lot!

I'm also trying to get deep DOF with wide angle lens (I've seen it done) though I'm thinking I just need a special lens for that, kit lens can't provide that. Is this correct?
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I think you're meaning shallow DOF, not deep DOF. If you're talking about a subject being in sharp focus and the background being soft and out of focus, that is shallow DOF. To achieve that with a wide angle lens, a fast aperture helps, but it can be done with the kit lens. You just need to have your subject very close to the lens. The closer you set your focus, the shallower the DOF gets. So, with the max aperture of the kits lens at f4, the only way to get decent shallow DOF of a person is to have a close-up of them standing a foot or so from the lens.
 
While you can wiggle around a bit by moving back and using a more telephoto setting, the other alternative is getting closer to your subject. Basically depth of field is greatly affected by subject to camera distance versus subject to background distance. If you reduce the subject to camera you will get better isolation.

HOWEVER, realize that if you want to keep the same framing of your subject, you're really just "wiggling" around with all this getting closer/farther/zooming/etc.. What you need is a wider aperture, using a 2.8 zoom or a brighter prime is the ONLY way you're going to get significant gains.

Realize that if you "get farther away and use a telephoto setting" you're also increasing your subject to camera distance, which will make your depth of field deeper, you'll make some of that plus a *bit* because of it being telephoto. If you move closer, even with a wider setting, you will get more subject isolation, however of course you may hamper your subject's framing and maybe get perspective distortion.

realize also that telephoto settings will make your background bigger (compressed), and wider settings will look more 3D and there will be more background visible.

Good luck... I suggest getting a brighter lens!
 
Thanks for the reply

HOWEVER, realize that if you want to keep the same framing of your subject, you're really just "wiggling" around with all this getting closer/farther/zooming/etc.. What you need is a wider aperture, using a 2.8 zoom or a brighter prime is the ONLY way you're going to get significant gains.
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Yeah, like I said I have quite a few Pentax lens including a 28mm and a 50mm 2.8 lens. I hope to get the adapter soon to try them out :)
 
This acronym, DOF, gets tossed around often "mindlessly" so it's no wonder it's often misunderstood. It stands for "Depth Of Field" which is in itself merely a "label" for the "Zone Of Acceptable Sharpness". This zone is affected by lens focal length, lens aperture, camera to subject distance, and subject to background elements distance.

There is no sharp line of delineation that defines where this zone begins and ends, from the "front" of the zone there is some transition from totally unsharp to not so unsharp to somewhat sharp and then to sharp. At the far end the transition works in reverse. With wide angle optics the transition into and out of the zone can be itself pretty short, but even with telephoto lenses it can be hard to "see" the transition itself.

Craig, take that 14-140 lens and "explore" it. Forget needing or ordering special lenses or accessories, that lens will do what you need in the way of "Depth Of Field Control" if you will learn the concept then try to see by looking through the lens. See my previous post with the three "factors", and print those on a reference card. To see what your aperture is really doing to DOF use whatever DOF prevue button the GH2 has (I don't have that camera myself) so you can "see" the effect.
 
Three ways to get a fuzzy background behind your main subject (=shallow DoF):

1) back away and use your zoom at the telephoto end

2) Get really, really close and use the wideangle end

3) switch to a fast prime like a 50mm f1.4 or 35mm f1.8

Which option you choose depends on the perspective effect that suits best.

In all three cases, have your aperture setting wide open.
 
Once that 17mm f/0.95 Voigtlander lens is released, I think you'll be seeing a lot more "5D"-like shallow DOF from the GH2.
 
sunny_j said:
you should zoom in with the lens and move far back as possible to achieve shallow dof.
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DPStewart said:
Yes. This even worked on my DVX100 video camera. So it is solid advice.
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i hope you guys read Mr. Foreman's first post, above. he offered a very good explanation. the idea that you want to get as far away from your subject as possible to decrease DOF is a common misconception. DOF increases as your point of focus gets farther from the lens. and as you get further into the telephoto end of a lens, there are even fewer depth cues in your field of view, making the image very flat.
 
Most any fast prime 2.8 and below, will give you some great shallow dof. Just shoot wide open and close as possible to your subject and you're golden!
 
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