DOF question. Making it happen.

AMOMENT · Oct 3, 2011

I am working on applying different DOF settings. I understand the concept. Usually for close-ups, you want a shallow depth of field correct? When you want more of the picture in focus than you want to increase your DOF. If you are trying to photograph a landscape, than you most likely want a much higher f-stop number and you therefore either have to bump up the ISO or slow the shutter to allow more light in...right?
I guess what I am struggling with now is reading my DOF on my camera. I have a Nikon d3100. I think there is a place to view it because when I look through my viewfinder there are numbers on the bottom in red ; what they mean, I have no idea. I have seen some online DOF calculators which seem helpful if you have the time to calculate before each shot. This is not practical because I shoot children alot. I am also doing some free shoots (so far family loved pics!) and I am literally changing positions every second to capture precious moments. . Any suggestions? If I was doing posed pics with a tri-pod than this would make more sense.

Well, I'll take any advice you can give me!! I have been shooting RAW or rawfine jpg. I almost always have to increase the saturation and contrast and I sometimes highlight my subject and brighten just them. I also sharpen the eyes. These seem to be my standard tweaks. Sometimes I find my pics are a little washed out. I'm guessing this is just me learning to work with the light. Last but not least in relation to focus and DOF, I have 11 auto focus points on my camera. I usually select the middle ones because they have cross points right? Which is good for shooting kids? I can only shoot one point at a time. have read and gathered that you usually want your focus to be on the eyes of your subject. Do I focus the point in between the subject's eyes so that their face is sure to be in focus? What if there is more than one person? My guess is to center my focal point in the "crowd" and to then increase my aperture to increase my DOF while moving father from my subject. Am I correct?

tevo · Oct 3, 2011

Nothing in your camera will indicate Depth of Field >_> You will only see the ISO, Shutter, and Aperture. Higher f/stop (smaller aperture) = more in focus, Lower f/stop (wider aperture) = less in focus (shallow DoF). If you are closer to your subject , and focus to them, you have a shallower DoF / vice versa.

480sparky · Oct 3, 2011

DOF doens't care if you shoot raw, jpeg, tiff, heck, even film or digital. It's merely a product of the optics. All the post processing won't increase it.... it's something that has to be captured in the field.

As for macros, you don't necessarily always want a shallow DOF. Shooting a small flower, for instance, you may want a deeper DOF just to show the viewer of the final image what it is.

Stopping your lens down to minimum may increase your DOF, but it also exaggerates other optical characteristics that aren't wanted. Most lenses are sharpest in the f/8-f/11 neighborhood.

Another thing you may want to look into for macros is focus stacking.

BuS_RiDeR · Oct 3, 2011

Watch this... It may help.

DoF Video

AMOMENT · Oct 3, 2011

Also, on the actual lens of my camera are a few numbers and what I know to be the infinite symbol. When and why would I apply these adjustments?

tevo · Oct 3, 2011

AMOMENT said:
Also, on the actual lens of my camera are a few numbers and what I know to be the infinite symbol. When and why would I apply these adjustments?

That is the focal length.. I would go read about how a DSLR works, investigate focal length, exposure triangle, and general DSLR use.

AMOMENT · Oct 3, 2011

I'm mainly interested in shooting people.

tevo · Oct 3, 2011

AMOMENT said:
I'm mainly interested in shooting people.

Investigate focal length / exposure triangle.

BuS_RiDeR · Oct 3, 2011

AMOMENT said:
Also, on the actual lens of my camera are a few numbers and what I know to be the infinite symbol. When and why would I apply these adjustments?

Sorry, I edited my response... It was completely wrong... Sorry.

BuS_RiDeR · Oct 3, 2011

AMOMENT said:
I'm mainly interested in shooting people.

That's illegal... You can get in a lot of trouble for just saying that! :lmao:

MTVision · Oct 3, 2011

AMOMENT said:
I am working on applying different DOF settings. I understand the concept. Usually for close-ups, you want a shallow depth of field correct? When you want more of the picture in focus than you want to increase your DOF. If you are trying to photograph a landscape, than you most likely want a much higher f-stop number and you therefore either have to bump up the ISO or slow the shutter to allow more light in...right?
I guess what I am struggling with now is reading my DOF on my camera. I have a Nikon d3100. I think there is a place to view it because when I look through my viewfinder there are numbers on the bottom in red ; what they mean, I have no idea. I have seen some online DOF calculators which seem helpful if you have the time to calculate before each shot. This is not practical because I shoot children alot. I am also doing some free shoots (so far family loved pics!) and I am literally changing positions every second to capture precious moments. . Any suggestions? If I was doing posed pics with a tri-pod than this would make more sense.

Well, I'll take any advice you can give me!! I have been shooting RAW or rawfine jpg. I almost always have to increase the saturation and contrast and I sometimes highlight my subject and brighten just them. I also sharpen the eyes. These seem to be my standard tweaks. Sometimes I find my pics are a little washed out. I'm guessing this is just me learning to work with the light. Last but not least in relation to focus and DOF, I have 11 auto focus points on my camera. I usually select the middle ones because they have cross points right? Which is good for shooting kids? I can only shoot one point at a time. have read and gathered that you usually want your focus to be on the eyes of your subject. Do I focus the point in between the subject's eyes so that their face is sure to be in focus? What if there is more than one person? My guess is to center my focal point in the "crowd" and to then increase my aperture to increase my DOF while moving father from my subject. Am I correct?

You can't read the DOF on your camera. The stuff in your viewfinder is your shutter speed, aperture, iso etc.

Usually to let more light in you open up your lens (lower the aperture). With landscape you don't have to bump your ISO up - its all dependent on the light. You don't always have to use the center point! Are you focusing with center point then recomposing the shot? I read somewhere (not sure if it's right) but if you have a group of people, say 5, you would want you aperture set to around f/5 to get them all in focus.

The more you practice the more you will understand DOF.

With one person you focus on the eye closest to you. To get the whole face in focus you don't want to be shooting with your lens wide open (f/1.8).

For groups You don't have to open your aperture then Move farther. Set yourself where you need to be and close your lens down some (higher f #) so that you get all the people in focus.

Your RAW pictures may look washed out because the camera hasn't done any processing to them.

889Media · Oct 3, 2011

Most likely this refers to the aperture value your lens is using? At infinity, you will have as much as possible in focus (large DoF) whereas at say f2.8... you will have very little in focus (shallow DoF)...

I think you are slightly off on that one! The numbers that goes from one number to the infinity symbol is the focus point of the lens and indicates how far away from the camera the focus will be. The focal length of the lens is indicated by mm, and the aperture range of the lens are only mentioned on the lens - by the lowest number the lens is capable of. And even when focus point is set to infinite, you can still select to have a wider or shallower DoF by adjusting the aperture.

This is most used when in manual focus. In auto focus these values you talk about just go back on forth and in most cases I don't even pay attention to them. In manual focus though it is a great indicator for where you put your focus. Like if shooting the moon that is "almost like infinite distance away" compared to most distances you shoot down on the ground, you will set your focus to about infinite - and be pretty close to having a sharp focus on the moon.

That is the focal length.. I would go read about how a DSLR works, investigate focal length, exposure triangle, and general DSLR use.

No lens can have an focal length that goes to infinity... not yet at least

That's illegal... You can get in a lot of trouble for just saying that!

And...LOL!

(Edited due to some smaller changes and additional inputs)

radiorickm · Oct 4, 2011

I am posting a couple of pictures of lens only for educatioal purposes, they are NOT my photos.

I am not a Nikon shooter, but I went and got an image of an older Nikon lens that may help you see whats happening. This is hard to explain, but I'll try.

I will assume (yeah..I know) that the Nikor lens you are using looks someting close to that. The numbers visible through the window represent the camera to subject distance. This is one of the three things that will effect DOF. This distance is usually also included in your EXIF data.

There are many online DOF calculators to use, but in the OLD days, there was one on the lens barrel.

If you look at this lens, you will notice a big white line right in the middle of the lens. (This particular lens is focused on infinity, and I couldn't find an image of one that wasn't).
You will also notice that there are two sets of numbers, one on each side of the white mark. These refer you your aperature.

Now, as you focused the lens, you turn the outer ring, and the distance scale (where the infinity mark is) rotates to indicate your camera to subject distance.
In the photo, you are focused on a subject that is at infinity. The numbers on each side of the white mark, the "22" and the "11" represent setting your aperature to that setting.
The "distrances" set above the left "22" number, and the right "22" number, would represent the Depth of Field for an aperature of F22. In the photo everything from about 10' through infinity would be in focus (if the lens were set to F22[the picture shows it at F5.6])

NOW imagine this: turn the focus ring until the "7" is right over the white center line. and the aperature were still at F22.

20***** 7******** 4 feet
-----------|----------
22******|********22

Now the DOF would mean that everything from 20' to 4' would be in focus if you used an aperature of F22.

Lets narrow it down a bit now, and with the same DISTANCE, use an F stop of F11. You will notice that the F11 marks are closer together (closer to the white focus mark).

20***** 7******* 4 feet
-----------|----------
22** 11* |* 11*** 22

Now, if you set your aperature to F11, things from a distance of maybe 6' to 10' would be in focus.

So now we kinda see whats happening, you can apply that. The closer you get to the subject, the DOF is going to reduce. The larger the aperature, the more the DOF is going to reduce. And, the longer the focal legnth, the more the DOF is going to reduce.

If you are trying to get a shallow DOF with a lens at 28mm

Now, you will notice that there is not enough room for the numbers on each side of the focus mark (in this case the black dot), but a colored line. Look at the aperature values, and they are colored to match the lines. F22 is ORANGE.

So, if we focus on a subject that is 5' away, it will look like this

15**********5************ 3
-----------------|------------------
22*********************** 22

then everything from 3' to 15' would be in focus using F22.

But notice this lens has different marks, so let look at a f-stop of F5.6 (the red marks on the lens)

15********** 5************ 3
-----------------|------------------
*********5.6**5.6***********

Now maybe things from 4' to 6' would be in focus.

Of course, the other way around, if you set your ring with the infinity symbol on the left "22" then the 2 would be over the right "22" so everything from 2' to infinity would be in focus.

I went from 50mm to 28mm in my example, but if you go out to 135 or so the opposite thing happens.

I hope this kinda shows you how we did it in the old days, and how the focal legnth, aperature, and subject distance all affect the DOF