depth of field

[ajmall]

right i know what it is but i don't how to use it to my advantage. i was doing some studio work for the first time the other week but a few shots didn't have a good depth- face was in focus and ear and some hair was out of focus.

i was using a 28/200mm F3.5/5.6 lens at around 80-100mm mainly on F4 if that helps. i've got a Nikon F80/N80 that has a d.o.f preview too but it never seems to change!

 

[voodoocat]

at 100mm I go with about f5.6 to the the whole head in focus.

 

[Big Mike]

At F/4 there is not a lot of DOF. Stop down to get more. If you like the shallow DOF, try to make sure that the subject's eyes are in crisp focus.

You won't see much of a difference with DOF preview unless you are set to shoot at a small aperture...like F/16 or F/22...then you will notice a difference but the viewfinder will get pretty dark as well.

Do your lenses have a scale on them? Older lenses has distance scales that would tell you the distances that would be in focus.

If you search around, you could find distance tables for specific focal lengths.

 

[ajmall]

thanks thats helped me

 

[ksmattfish]

f/4 is pretty much wide open for your lens. You'll only see a change when using the DOF preview if you stop down some. Try it at f/8, f/16, etc... then you will see a difference.

 

[markc]

As far as using it to your advantage, when you want most everything in focus, you would use a narrow aperture to get a long DOF, like this:

Note that both the corn and the contrails are in focus.

Sometimes you want to use a wide aperture to get a very small DOF to set a mood, like this:

And then there's times when you want to have all of your subject in focus, but only blur out a distracting background, in which case you would pick something in between, like this:

In this case the two girls in the front are the main subjects and they are completely in focus, but the third girl is a little blury, creating some separation without making her part of the background, and the background is blurred enough to not steal your attention from the girls.

 

[dave k]

Hi all
A good way to learn DOF is to get 7 cans of beer line then up about 100mm apart and place your camera at 45 degrees to them, its best to use a tripod. Now focus on the 3rd can at min aperture (wide open) and take photo this can be done in shutter priority for ease. Then stop down until you reach max. then you should see the changes in your photos. now drink beer. The rule of thunb is 1/3 in front of the focal point and 2/3 behind
dave k

 

[Jay Carota]

now drink beer.

Ohhh.....you meant after you take the pictures? That makes much more sense. I drank the beer first and there was absolutely no DOF at all.

markc:

Thanks for the very informative post.

 

[soulfly]

Marc C. this was a very enlightening thread, you just cleared up all my fog about dof in one thread, thanks a million! I finally understand and can use it...(I'm such a dolt.... :roll: )

 

[markc]

Marc C. this was a very enlightening thread, you just cleared up all my fog about dof in one thread, thanks a million! I finally understand and can use it...(I'm such a dolt.... :roll: )

Hehe. No your not. There is just so much to learn about what each setting does. It's not easy to keep track of it all at once.

 

[ajmall]

Any advice given in the above post comes from a deranged madman. Implement at your own risk.

haha!