Aperture question

Rollei12 · Feb 4, 2015

I was out on a shoot and tried to take a picture of a tree. It was a mid-up (middle to top of tree) shot with mountains in the back. I figured I could work the settings like a do when shooting things close up and want a nice blurry background...open the aperture up wide.

So I shot the tree (200 feet away or less) at F3.5 (after zooming in some) and set everything else accordingly for a correct exposure. When the photos from the roll came back from the developer everything in that shot was in focus. Nothing was blurry. What did I do wrong? How can I "throw" the depth of field further ahead? Say a tree or some object is 200-500 feet away. How can I have that in focus but the background out of focus?

480sparky · Feb 4, 2015

This really isn't a film question (unless the issue is with the film), but more a lens question.

What focal length were you using?

photoguy99 · Feb 4, 2015

That is going to be pretty hard.

I would suggest focusing on something closer than the tree. If you focus on one thing, stuff closer and further away is still pretty sharp, right? The amount of stuff that's sharp is your depth of field.

Put the tree at the very back of the stuff that's pretty sharp. So stuff up real close is sharp. You're focused, maybe, halfway between yourself and the tree, and the tree is still pretty sharp too, but after that it starts to get soft. If you're lucky the mountains will be a blur.

Experiment. Take a lot of shots. Bits are free.

You were probably shooting at what's called hyperfocal distance (you can just look that up on Wikipedia where the explanation will be better than what I can dash out)

480sparky · Feb 4, 2015

photoguy99 said:
....... Take a lot of shots. Bits are free........

Ummmmm.......

Rollei12 said:
........... When the photos from the roll came back from the developer .........

Light Guru · Feb 4, 2015

Rollei12 said:
I shot the tree (200 feet away or less) at F3.5

Your too far away.

Ysarex · Feb 4, 2015

Simple answer is you can't. Your tree is too far away and the magnification is too small -- the background will be in focus.

Let's say you moved up to an 8x10 camera -- that'll help with the magnification problem. Then if the tree isn't too tall at 200 feet you could frame it with a 360mm lens. That lens is going to be wide open at f/5.6 -- you've still got 300 feet of DOF. Want to move up to an 11x14 inch camera?

Joe

photoguy99 · Feb 4, 2015

Good point about the bits. Film is not free

Let me amend that. Get a digital camera of similar characteristics to your film camera, and experiment with that! Bits are free!

photoguy99 · Feb 4, 2015

Fussing around on dofmaster suggests strongly that you're not going to get the mountains to be a blur no matter what. You can make them look, I think, distinctly soft, but they'll look mildly out of focus, not actually 'a blur'

It's optics and it's complicated. Depth of field gets bigger pretty fast as distances increase.

Rollei12 · Feb 4, 2015

Ysarex said:
Simple answer is you can't. Your tree is too far away and the magnification is too small -- the background will be in focus.

Let's say you moved up to an 8x10 camera -- that'll help with the magnification problem. Then if the tree isn't too tall at 200 feet you could frame it with a 360mm lens. That lens is going to be wide open at f/5.6 -- you've still got 300 feet of DOF. Want to move up to an 11x14 inch camera?

Joe

Thanks. The question is about taking what I can do with a flower and putting that towards something far away. If I can take a photo of a flower and have bushes in the background blurry, I wanted to put that towards a tree 200 feet away and have the mountains behind that blurry. I guess I can't do that now

weepete · Feb 5, 2015

You should be able to do it but probably not at the distance you want. It sounds to me like you need to think about it slightly differently and use a wider lens to get closer to the tree which in theory could keep the same framing but throw the background out of focus. Or you could always blur the background more in post. You may also need a larger aperture than 3.5 depending on the situation.

What focal length were you using?

compur · Feb 5, 2015

Depth of Field isn't only dependent on aperture. It also decreases with lens focal length and increases with lens distance to subject.

Ysarex · Feb 5, 2015

Rollei12 said:
Ysarex said:

Simple answer is you can't. Your tree is too far away and the magnification is too small -- the background will be in focus.

Let's say you moved up to an 8x10 camera -- that'll help with the magnification problem. Then if the tree isn't too tall at 200 feet you could frame it with a 360mm lens. That lens is going to be wide open at f/5.6 -- you've still got 300 feet of DOF. Want to move up to an 11x14 inch camera?

Joe

Click to expand...

Thanks. The question is about taking what I can do with a flower and putting that towards something far away. If I can take a photo of a flower and have bushes in the background blurry, I wanted to put that towards a tree 200 feet away and have the mountains behind that blurry. I guess I can't do that now

It's the nature of the beast as they say. DOF distilled down is a function of magnification and f/stop. You can swap things around like lens focal length and how far away you are but in the end it all boils down to magnification and f/stop with magnification being the dominant factor. When you photograph a flower the magnification is high. Conceivably a very tiny flower can be photographed at a magnification of X1 -- in other words the image of the flower on your film is physically the same size as the flower. As objects get bigger (and film/sensors are pretty small) you quickly get into magnifications of X.0x where the image of the object on film is a small fraction of the real size of the object. As magnification decreases DOF increases rapidly. The effect of the lens f/stop only goes so far -- it is a lesser effect.

200 feet is pretty far away even for a large tree, but at half that distance (100 feet) you'll still have the same basic situation. You're likely working at a magnification of X.00x. You can increase magnification by making the film bigger, that's why I mentioned the 8x10 camera, but realistically we're all walking around with tiny little pieces of film and/or even smaller sensors. So if you're going to frame a large tree and leave some room to place it in the environment and you're using a hand camera of some type, even at f/2 it's all going to be within the limits of DOF -- DOF will reach infinity behind the tree.

Joe

480sparky · Feb 5, 2015

Full-frame SLR.
100mm lens @ f/3.5
Focus at 200 ft.
FOV is 72 x 48 ft.
DOF is 169-276 ft.

But that's just one possible scenario. We'd need to know what focal length was used.

timor · Feb 5, 2015

Rollei12, maybe time to read something. It may improve an understanding of terms you and we are using. Donald Krehbiel has nice and informative website called "Minox, Metol & Macintosh". Read it.

sm4him · Feb 5, 2015

Rollei12 said:
Ysarex said:

Simple answer is you can't. Your tree is too far away and the magnification is too small -- the background will be in focus.
Joe

Click to expand...

Thanks. The question is about taking what I can do with a flower and putting that towards something far away. If I can take a photo of a flower and have bushes in the background blurry, I wanted to put that towards a tree 200 feet away and have the mountains behind that blurry. I guess I can't do that now

Sure you can. You just need an ITTY, BITTY little tree, so you can get close enough to it and still have it in the frame with the mountains in the background. I'd suggest taking a bonsai tree out with you. Set it down on a hill with the mountains in the distance, and BOOM! In-focus tree, out of focus mountains!! :laughing: