Depth of Field

canon400d

I am a new learner and I use a Canon 400D. I have finished using the Auto setting and I advanced myself onto 'P' mode because it automatically sets the aperture and shutter speed. I was advised by Davev who has been most helpful and he suggested using 'A' mode to give more control over the camera. I select the aperture and ISO and the shutter speed is automatically set.
I have read over and over again about the Depth of Field and I think I have a good knowledge of how the aperture and shutter works. Also the F. Stops and the different lens apertures and distance from subject.
Where I am totally confused is knowing exactly what size of aperture F number to use whilst taking different shots. Is this entirely guess work and take pot luck or what? I am thinking about the time it takes to set the camera and during which time you have missed that golden opporunity in securing the shot. I have looked at the Depth of Field calculator which was given to me on here and although it is useful I find it difficult as I say to put it into practice.
I have taken out a "Digital Photography Success Package" by Amy Renfrew on www.DigitalPhotographySuccess.com and I have read about the Depth of Field but it does not cover the aspect where I am confused which I have aforementioned explained. Can anyone please explain to me in layman's terms what I can do.
Many thanks
Bob
Dumfries & Galloway

sirsloop

DOF depend on whats the distance to the subject and what aperture you are shooting at. There are scientific methods to figure out what the exact dof will be, but I go based on experience and instant feedback in the LCD screen. You can also use the DOF preview feature on Canon bodies.

I think you're heading in the right direction by switching away from the green box into Av or Tv modes. I'd play around with your lenses at different apertures, focal lengths, and distances to your subject to get a feel for it.

a good read - be sure to check out the sub links that go to dpreview, etc.
http://www.waynesthisandthat.com/dof.html

windoze

canon400d wrote:

I am a new learner and I use a Canon 400D. I have finished using the Auto setting and I advanced myself onto 'P' mode because it automatically sets the aperture and shutter speed. I was advised by Davev who has been most helpful and he suggested using 'A' mode to give more control over the camera. I select the aperture and ISO and the shutter speed is automatically set.
I have read over and over again about the Depth of Field and I think I have a good knowledge of how the aperture and shutter works. Also the F. Stops and the different lens apertures and distance from subject.
Where I am totally confused is knowing exactly what size of aperture F number to use whilst taking different shots. Is this entirely guess work and take pot luck or what? I am thinking about the time it takes to set the camera and during which time you have missed that golden opporunity in securing the shot. I have looked at the Depth of Field calculator which was given to me on here and although it is useful I find it difficult as I say to put it into practice.
I have taken out a "Digital Photography Success Package" by Amy Renfrew on www.DigitalPhotographySuccess.com and I have read about the Depth of Field but it does not cover the aspect where I am confused which I have aforementioned explained. Can anyone please explain to me in layman's terms what I can do.
Many thanks
Bob
Dumfries & Galloway

my .01 cent opinion ( adjusted for inflation of neurons )
get out of "p" mode and use manual ( or at least Av mode )....

use more wide open apertures for isolation of subjects ( shallow DOF ) and more closed down apertures for wide DOF. Want a nice "bird" shot with great bokeh - get out your telephoto lens and use a more wide open aperture like f/2.8, f/3.2 etc. Landscapes typically will have more DOF, especially if you want "sharpness" from foreground to backround. When shooting landscapes where you want everything "sharp" use smaller apertures like f/16 and f/22. Use middle of the road apertures for shooting silhouettes, scenes where most things at same distance or at infinity. If you want to take advantage of an optical law, you might want to consider this: most lenses on the market today will record optimal contrast and critical sharpness at their critical apertures of f/8 and f/11, so i use these apertures when DOF is not a critical concern ( example - portrait of a girl against a wall ) .

I tend to think in terms of bryan petersons concepts: story telling compositions when i want everything nice and sharp ( more closed down apertures), isolation / single theme subjects and i want to blur out distracting elements ( more open apertures ) and who cares what apertures ( f/8 and f/11 ) when DOF is not of great concern.

canon400d

sirsloop wrote:

DOF depend on whats the distance to the subject and what aperture you are shooting at. There are scientific methods to figure out what the exact dof will be, but I go based on experience and instant feedback in the LCD screen. You can also use the DOF preview feature on Canon bodies.

I think you're heading in the right direction by switching away from the green box into Av or Tv modes. I'd play around with your lenses at different apertures, focal lengths, and distances to your subject to get a feel for it.

a good read - be sure to check out the sub links that go to dpreview, etc.
http://www.waynesthisandthat.com/dof.html

Thanks ever so much I have found your reply most interesting and helpful to.
Kind Regards
Bob

Andy

windoze wrote:

....use more wide open apertures for isolation of subjects ( shallow DOF ) and more closed down apertures for wide DOF.
.
.
.

Look at our windoze, all growed up he is!



Bob, many of us here remember a time when windoze didn't know an f-stop from a door stop

canon400d

windoze wrote:

my .01 cent opinion ( adjusted for inflation of neurons )
get out of "p" mode and use manual ( or at least Av mode )....

use more wide open apertures for isolation of subjects ( shallow DOF ) and more closed down apertures for wide DOF. Want a nice "bird" shot with great bokeh - get out your telephoto lens and use a more wide open aperture like f/2.8, f/3.2 etc. Landscapes typically will have more DOF, especially if you want "sharpness" from foreground to backround. When shooting landscapes where you want everything "sharp" use smaller apertures like f/16 and f/22. Use middle of the road apertures for shooting silhouettes, scenes where most things at same distance or at infinity. If you want to take advantage of an optical law, you might want to consider this: most lenses on the market today will record optimal contrast and critical sharpness at their critical apertures of f/8 and f/11, so i use these apertures when DOF is not a critical concern ( example - portrait of a girl against a wall ) .

I tend to think in terms of bryan petersons concepts: story telling compositions when i want everything nice and sharp ( more closed down apertures), isolation / single theme subjects and i want to blur out distracting elements ( more open apertures ) and who cares what apertures ( f/8 and f/11 ) when DOF is not of great concern.

Thanks ever so much for your most helpful reply. I have sent you an email giving details of my lenses etc etc.
Kind Regards
Bob

canon400d

Andy wrote:

Look at our windoze, all growed up he is!



Bob, many of us here remember a time when windoze didn't know an f-stop from a door stop

Hi Andy,
Our Windoze has helped me out enormously with that reply. I have emailed him and told him so. It is me who is the door stop. I have just figured out what the F stops mean.
Best Wishes
Bob

windoze

Andy wrote:

Look at our windoze, all growed up he is!



Bob, many of us here remember a time when windoze didn't know an f-stop from a door stop

There is no difference between a door stop and a F-stop, they are very much the same. When you use a door stop you set the door at a specific opening to let an available quantity of something in. When you set a f-stop you select a specific opening to let in an available quantity of something "light" in...

whats the difference?

troy

sirsloop

a door stop is a piece of wood

wmstumme

sirsloop wrote:

DOF depend on whats the distance to the subject and what aperture you are shooting at. There are scientific methods to figure out what the exact dof will be, but I go based on experience and instant feedback in the LCD screen. You can also use the DOF preview feature on Canon bodies.

I agree with sirsloop. There are plenty of formulas--but the best way is just to go out and play with your camera and get a sense/experience with what the camera is going to do. Digital's are great--you can get instant feedback, and simply delete whatever you don't like.

In general you can expect to get a shorter DOF by using a wider aperture (the smaller numbers, like f2.8 etc) and having the subject you focus on close to you. Longer DOF (more in focus) comes from smaller apertures (the bigger numbers - f16, 22 etc...) and the subject being farther away. Longer telephoto lenses (300mm +) can get very short DOF, shorter lenses (like a 50mm) will have a much longer DOF for a subject the same distance away.

However, all these factors work in concert on every shot. You could sit with a slide rule and figure this all out--and there are probably some folks who do. I just try and "feel" how it is going to look--and with practice (which I still need a lot of) -- the shot should come our somewhat like you expected. If not, change one of your settings and see what happens...

Good luck

windoze

sirsloop wrote:

a door stop is a piece of wood

my history is really bad, but in the olden days, wasnt exposure controlled by removing "WOODEN" panels....... F-stops ( aperture) were selected by choosing these panels of wood!


see there is no difference.....

sirsloop

ya... a piece of wood

SloYerRoll

windoze wrote:

whats the difference?

troy

Doors are WAY cheaper!