Depth of Field???? DOF

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Depth of Field???? DOF

Depth of FIELD (or Focus)!!!!

Most simply stated depth of field is term used to describe how much or how little of your picture is in focus. There are several factors that determine the depth of field, but none is more profound then the aperture used to capture the image. A large aperture will result in LESS depth of field then a small one will. There are other factors as well, focal length, and the distance from the camera to the subject, but neither of these are as dramatic as aperture. Aperture along with ISO directly impact the shutter speed as well, so you can't change one without changing at least one of the other 2, but for this demonstration, I will only talk about the aperture.

So what is the difference between getting an image like this:

4.jpg


And this:

5.jpg


APERTURE!!!!

Those of you that keep your SLR camera on the GREEN SQUARE, or the "P" mode are really losing out. If you use the camera "program mode" you are allowing the camera to decide what results you are going to get, you are giving control to the camera rather then keeping control for yourself. Aperture is the single most dramatic control we have over the finished result of our images, once you learn to control the aperture, you can decide what the finished image will look like. In some cases you may want to have as much of the picture in focus as possible, in other cases you will want to isolate the subject from the background by using the largest aperture you can.

Okay... enough typing! Here is a progression of images from the largest aperture to the smallest, meaning the least in focus to the most in focus.

6.jpg

2.8

7.jpg

4.0

8.jpg

5.6

9.jpg

8.0

10.jpg

11

11.jpg

16

12.jpg

22

13.jpg

32

The scale from 2.8 to 32 are the "standard" f stops available on most cameras. Each stop allows in TWICE as much light as the next one, so from 2.8 to 4 is half the size. This is where the relationship between aperture and shutter speed is most evident, but that is topic for yet another thread!

As always, I hope you find the information presented here useful, and if you have any questions, please post them here!

-Mike
 
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LOL!!!! Next I have to do a "Shutter Speed" demo, but I need a spastic fish to chase around, and I don't have one. I may have to head over to my buddies place to chase around his Achilles tang.
 

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man, i was chasing my fish around for the longest time the other night. my flame angel was playing games with me, taunting me. he would go from one side of a rock, and pop on the other, then come out of a crevice; each time, coming face to face with me, but never long enough to snap a shot. i ended up switching to the sports setting and doing bursts. out of several hundred shots, this was the best (and not that good, even)

IMG_3325.jpg
 

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Trying to read over all of the stickys to learn as much as possible! You mentioned the "P" mode and that if the "P" mode is being used then the camera is taking control. The "P" mode is what I have been using..... If that is not the best mode to use what would you recommend? I have a Canon Rebel Xti.
Thanks!
 

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I missed this one! This is great!
 

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I agree, a lot of great information.
My wife says that I have officially lost my mind! I have been messing with my camera for hours trying to figure out all of the setting listed in the sticky's.
 

Saltysteele

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it's frustrating, trying to learn what everything does, but you'll get there :) mike and junior have been a tremendous help in this aspect (even though they're probably gettingn tired of me asking the same thing in a different way :p )

i'm still at the point where i think i understand something, and then find out i don't (story of my life) :haha:
 
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Trying to read over all of the stickys to learn as much as possible! You mentioned the "P" mode and that if the "P" mode is being used then the camera is taking control. The "P" mode is what I have been using..... If that is not the best mode to use what would you recommend? I have a Canon Rebel Xti.
Thanks!

See that is the thing, there is not really a setting that works for everyone. I can tell you that I use Av, set the aperture to F8, and ISO to 400, and that should be a good place to start, but I don't know what lights you have, how far away the coral is from that light, etc...

Do you have a tripod, or are you hand holding? See.. These are things that are different for everyone's tank.

Try the Av mode, and f8 at iso 400, and see it that works. You may or may not have to use exposure compensation to get a proper exposure, out lights tend to fool the camera's built in light meter.
 
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Poseidon

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Just in case there is not a really stable tripod. ISO 100 may mean shutter speeds in excess of 1 second. At ISO 400, the shutter speed should be faster then that, and shooting Canon, there is very little difference in noise between the 2. (Nikon is good too.)
 

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Thanks! I just wanted to make sure that the P mode had auto setting that would work against me. I have been using AV because I like the auto F stop feature of it.
Thanks again
 

cfmx

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Great info! Just order my tripod today. My friend is letting me use her different macro lens to play with.
 
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Poseidon

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I am glad you found it helpful, it is easy to see when it is all in one spot isn't it?
 

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