Depth Of Field

slimboy

slimboy

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luke
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hi all i know this may seem like a stupid question but how do you increase depth of field i can get some nice pictures of birds and other wildlife but i can always see to much in the background. i know i can edit it in photoshop but i would rather learn how to do it properly so i dont have to.

many thanks
luke
 
slimboy said:
hi all i know this may seem like a stupid question but how do you increase depth of field i can get some nice pictures of birds and other wildlife but i can always see to much in the background. i know i can edit it in photoshop but i would rather learn how to do it properly so i dont have to.

many thanks
luke
Click to expand...
Stop the lens down.
 
Hi Luke

Basically, the wider the aperture (Lower f number) the shallower the depth of field, BUT the closer you are to the subject and the further the subject is from the background, the shallower the depth of field. So therefore, the depth of field will be determined by a combination of those. Not 100% sure, but the focal length of the lens may also play a part.

HTH
 
After my shameful and foolish mistake earlier dare I poke my head in here?

DoF is a combination of aperture value and magnification. Magnification is a combination of focal length and distance to subject. Basically the bigger the subject in the frame and the wider the aperture value the less DoF you'll have.

Oh dear I'm sure I'm right but my confidence is all shot :lol:
 
slimboy said:
how do you increase depth of field i can get some nice pictures of birds and other wildlife but i can always see to much in the background.
Click to expand...

It sounds like you want to decrease DOF not increase.
As said before, use a wider aperture (lower f/number) and using a longer focal length also decreases DOF. For birds you are most likely using your longest lens anyway, so that only leaves the aperture.
 
thank you to all on your help i have been using my sigma 75-300mm at full zoom to capture the birds i thook a shot of two starlings on my feeder today at full zoom iso 200 shutter speed 1/30 and at f6 which only blured a little so i tried again with f18 and a faster shutter speed but it was not much different am i doing anything wrong?:( the lens is for a film camera but its all i can afford for now till i get back to work in the new year.
 
cyclone said:
It sounds like you want to decrease DOF not increase.
As said before, use a wider aperture (lower f/number) and using a longer focal length also decreases DOF. For birds you are most likely using your longest lens anyway, so that only leaves the aperture.
Click to expand...

sorry yes thats what i ment:bang::bang: told you it was a stupid question:cuckoo:
 
slimboy said:
thank you to all on your help i have been using my sigma 75-300mm at full zoom to capture the birds i thook a shot of two starlings on my feeder today at full zoom iso 200 shutter speed 1/30 and at f6 which only blured a little so i tried again with f18 and a faster shutter speed but it was not much different am i doing anything wrong?:( the lens is for a film camera but its all i can afford for now till i get back to work in the new year.
Click to expand...

Your going the wrong way- you need a smaller f number not bigger and you may need to be closer to your subject. like these - which show shutter / aperture values
 
yeah stop down the lens ie anything over f16 at least and they should have more sharpness throughout the picture and its reversly if you would a shallow depth of field use a smaller f stop ie f5.6 ect...

play about with them to see properally how they work
 
cyclone said:
It sounds like you want to decrease DOF not increase.
Click to expand...

We recently had an argument at our Photography Club (based on a question in our christmas quiz we had) about what f-stop gives you the greatest depth of field.

I argued that f/32 would whereas other argues that it would be f/2 (out of 2, 16 or 32) meaning that it gave you the greatest bokeh or greatest narrowing of depth of field (which is what most people understood the question to be).

How do people here intrept the question?
 
Uneducated_Rick said:
We recently had an argument at our Photography Club (based on a question in our christmas quiz we had) about what f-stop gives you the greatest depth of field.

I argued that f/32 would whereas other argues that it would be f/2 (out of 2, 16 or 32) meaning that it gave you the greatest bokeh or greatest narrowing of depth of field (which is what most people understood the question to be).

How do people here intrept the question?
Click to expand...

To me, greatest depth of field means the most area of the photo in focus, so you were right! :thumbs:
 
Uneducated_Rick said:
We recently had an argument at our Photography Club (based on a question in our christmas quiz we had) about what f-stop gives you the greatest depth of field.

I argued that f/32 would whereas other argues that it would be f/2 (out of 2, 16 or 32) meaning that it gave you the greatest bokeh or greatest narrowing of depth of field (which is what most people understood the question to be).

How do people here intrept the question?
Click to expand...

You were right, Rick.

Whatever could "greatest narrowing of depth of field" mean?:cuckoo:

Surely the opposite of greatest in this context is least or narrowest? (and f2)
 
Yeah it's a bit like asking what end of the pool give you the greatest depth, deep or shallow?
 
Larger DOF to me means smallest aperture (Biggest F number) which will give a larger area in focus in front and behind the focal point of the camera.
 
The smaller the f#, i.e. 2.8, 4, 5.6 the more light you'll let onto the sensor or film so increasing your shutter speed, allowing you freeze the birds motion. The side effect of this is that the smaller the f# the smaller the depth of field, so you get a blurred background :)

Thats the simplified version, it will depend on how far you are away from your subject for the exact dof.

Gerald
 
It's not an accurate measuring tool, but the easiest way to remember which way round the DPF and aperture work, is to imagine the f number represents the distance from the lens that will be in focus.

As such, f/2.8 will give you less of the shot in focus than, say, f/8.0.

As I say, it doesn't actually measure up like that, but it's a handy reminder as to which way you need to take the f-stop to have either less or more of the shot in focus.
 
DM got there with the link before me LOL.

Needless to say... Focal length/Aperture/Distance to subject are the three variables (or a constant if using a prime lens)
 
pxl8 said:
DoF is a combination of aperture value and magnification. Magnification is a combination of focal length and distance to subject. Basically the bigger the subject in the frame and the wider the aperture value the less DoF you'll have.

Oh dear I'm sure I'm right but my confidence is all shot :lol:
Click to expand...

Dead right, clearly and simply put :)

The only thing to qualify is magnification, which is often related to format size, ie a frame filler on full-frame is obviously a larger image than a frame-filler on crop-format, which means the full-frame image has less depth of field, by a factor of about 1.25 stops (Nikon/Canon). This also explains why the relatively tiny format of compacts and (even more so) camera phones give enormous depth of field.

Telephotos do NOT automatically give less depth of field, but they usually give bigger magnifications, which of course does - an important difference. However, their narrow field of view which cuts out so much background behind the subject always gives the impression of more shallow depth of field, even though it's technically an illusion.

Richard.
 
The way I look at it is that DOF can also stand for Depth Of Focus.

So the greater the DOF the more you can have in focus.


Bit simplistic but so am I :D
 
A few minunderstandings in this thread...
cammiedh13 said:
yeah stop down the lens ie anything over f16 at least and they should have more sharpness throughout the picture and its reversly if you would a shallow depth of field use a smaller f stop ie f5.6 ect...

play about with them to see properally how they work
Click to expand...
Yes, at any given focal length a higher f/number does produce greater depth of field. But if the aperture is too small then diffraction limitation starts to kick in, this reduces the overall sharpness.
As a rough guide, with a good quality lens diffraction limitation starts to rear its ugly head at any aperture smaller than f/11 on a cropped sensor camera, f/16 at full frame. If the lens isn't very sharp then the effect of diffraction may not be so obvious.

The way I look at it is that DOF can also stand for Depth Of Focus. Depth of Focus is something entirely different to Depth of Field. Depth of Field relates to what happens in front of the lens, Depth of Focus relates to what happens behind the lens.

DoF is a combination of aperture value and magnification. Magnification is a combination of focal length and distance to subject. Basically the bigger the subject in the frame and the wider the aperture value the less DoF you'll have. That's along the right lines. it isn't aperture value (f/number) though, it's actual or effective aperture, which is very different.
 
Garry Edwards said:
A few minunderstandings in this thread...

Yes, at any given focal length a higher f/number does produce greater depth of field. But if the aperture is too small then diffraction limitation starts to kick in, this reduces the overall sharpness.
As a rough guide, with a good quality lens diffraction limitation starts to rear its ugly head at any aperture smaller than f/11 on a cropped sensor camera, f/16 at full frame. If the lens isn't very sharp then the effect of diffraction may not be so obvious.

The way I look at it is that DOF can also stand for Depth Of Focus. Depth of Focus is something entirely different to Depth of Field. Depth of Field relates to what happens in front of the lens, Depth of Focus relates to what happens behind the lens.

DoF is a combination of aperture value and magnification. Magnification is a combination of focal length and distance to subject. Basically the bigger the subject in the frame and the wider the aperture value the less DoF you'll have. That's along the right lines. it isn't aperture value (f/number) though, it's actual or effective aperture, which is very different.
Click to expand...

:agree:
 
Garry Edwards said:
A few minunderstandings in this thread...

Yes, at any given focal length a higher f/number does produce greater depth of field. But if the aperture is too small then diffraction limitation starts to kick in, this reduces the overall sharpness. As a rough guide, with a good quality lens diffraction limitation starts to rear its ugly head at any aperture smaller than f/11 on a cropped sensor camera, f/16 at full frame. If the lens isn't very sharp then the effect of diffraction may not be so obvious.
Click to expand...

In your last sentence you contadict yourself, either diffraction has something to do with depth of field, or it doesn't. Actually, it doesn't, as depth of field is a purely mathematical calculation made regardless of lens. Furthermore, in my view a lot of scare stories are written about diffraction ruining lots of shots. It doesn't, and I would not hesitate to use f/16 or f/22 is that's what I needed to get enough depth of field (might baulk at f/32 though :lol: ). However, the resulting slow shutter speed might blur the picture - maybe this is what you're getting ;)

Garry Edwards said:
DoF is a combination of aperture value and magnification. Magnification is a combination of focal length and distance to subject. Basically the bigger the subject in the frame and the wider the aperture value the less DoF you'll have. That's along the right lines. it isn't aperture value (f/number) though, it's actual or effective aperture, which is very different.
Click to expand...

What's the difference between "aperture value (f/number)" and "actual or effective aperture"? Semantics are important (and I agree about the important distinction between depth of field and depth of focus) but I don't get this one.

Thanks :)

Richard
 
Uneducated_Rick said:
We recently had an argument at our Photography Club (based on a question in our christmas quiz we had) about what f-stop gives you the greatest depth of field.

I argued that f/32 would whereas other argues that it would be f/2 (out of 2, 16 or 32) meaning that it gave you the greatest bokeh or greatest narrowing of depth of field (which is what most people understood the question to be).

How do people here intrept the question?
Click to expand...

I keep seeing this on flickr and it makes me angry every time. At the moment (it hasn't always been this way) a shallow depth of field is very much in vogue. The hipster lot on flickr are commenting on photos with a shallow depth of field with "Wow, that's got loads of DoF!" There's no use in trying to correct them as they tend to get quite angry. Oh well.
 
Blapto said:
I keep seeing this on flickr and it makes me angry every time. At the moment (it hasn't always been this way) a shallow depth of field is very much in vogue. The hipster lot on flickr are commenting on photos with a shallow depth of field with "Wow, that's got loads of DoF!" There's no use in trying to correct them as they tend to get quite angry. Oh well.
Click to expand...

Young people today ....I don't know .... think they know it all.... when they've ..... etc, etc....:)
 
slimboy said:
thank you to all on your help i have been using my sigma 75-300mm at full zoom to capture the birds i thook a shot of two starlings on my feeder today at full zoom iso 200 shutter speed 1/30 and at f6 which only blured a little so i tried again with f18 and a faster shutter speed but it was not much different am i doing anything wrong?:( the lens is for a film camera but its all i can afford for now till i get back to work in the new year.
Click to expand...
THIS THREAD IS MADNESS GONE MAD:bonk:
 
HoppyUK said:
In your last sentence you contadict yourself, either diffraction has something to do with depth of field, or it doesn't. Actually, it doesn't, as depth of field is a purely mathematical calculation made regardless of lens. Furthermore, in my view a lot of scare stories are written about diffraction ruining lots of shots. It doesn't, and I would not hesitate to use f/16 or f/22 is that's what I needed to get enough depth of field (

Richard
Click to expand...
Perhaps I should have explained in detail.
Diffraction limitation becomes very obvious at small f/numbers provided that the lens is sharp. Some lenses though are unsharp at any aperture, and if the lens never produces a sharp image then it's less obvious when diffraction limitation kicks in.
BTW, diffraction limitation isn't a line in the sand that you can't cross. The process is fairly gradual, my suggestion of f/11 on a cropped frame sensor simply means that it won't be seen at anything wider than that, not that it will necessarily be unacceptable at a smaller aperture - that's a subjective judgement, and sometimes it can be better to sacrifice resolution for depth of field.

QUOTE=HoppyUK;1132931]
What's the difference between "aperture value (f/number)" and "actual or effective aperture"? Semantics are important (and I agree about the important distinction between depth of field and depth of focus) but I don't get this one.

Thanks :)

Richard[/QUOTE]
the f/number is a mathmatical calculation, e.g. f/4 is 1/4th of the focal length of the lens, f/16 is 1/16th of the focal length of the lens etc.
Aperture is the actual diameter of the hole that lets the light through and this is what affects DOF.
Example: F100, f/10 = 10mm actual aperture (100 divided by 10 = 10.
F20, f/10 = 2mm actual aperture (20 divided by 10 = 2)
What this means it the the depth of field at f/10 on a 100mm lens is the same as on a 20mm lens at f/2 (although of course magnification is the other main factor, but my answer is right if all other things are equal)

Hope this helps
 
slimboy said:
hi all i know this may seem like a stupid question but how do you increase depth of field i can get some nice pictures of birds and other wildlife but i can always see to much in the background. i know i can edit it in photoshop but i would rather learn how to do it properly so i dont have to.

many thanks
luke
Click to expand...
Send me your Email address And I will send you a prog that I wrote.
oldfella
 
Garry Edwards said:
Perhaps I should have explained in detail.
Diffraction limitation becomes very obvious at small f/numbers provided that the lens is sharp. Some lenses though are unsharp at any aperture, and if the lens never produces a sharp image then it's less obvious when diffraction limitation kicks in.

QUOTE=HoppyUK;1132931]
What's the difference between "aperture value (f/number)" and "actual or effective aperture"?

the f/number is a mathmatical calculation, e.g. f/4 is 1/4th of the focal length of the lens, f/16 is 1/16th of the focal length of the lens etc.
Aperture is the actual diameter of the hole that lets the light through and this is what affects DOF.
Example: F100, f/10 = 10mm actual aperture (100 divided by 10 = 10.
F20, f/10 = 2mm actual aperture (20 divided by 10 = 2)
Click to expand...

Hello Gary,

With respect mate, I think you are introducing complications that are unhelpful because they are irrelevant to the subject of depth of field. Diffraction is just one of many factors affecting image sharpness and arguably one of the least significant. What about CA, which is usually much more prominent?

Sorry, but your explanation of f/numbers and apertures etc has me none the wiser. Again you are making the subject more complicated than it needs to be by introducing unnecessary distinctions. Your statement "Aperture is the actual diameter of the hole that lets the light through and this is what affects DOF" gets us nowhere. The "diameter of the hole" means nothing by itself in relation to depth of field.

And the common understanding of the term "aperture" is the f/number. Eg ask any photographer what aperture they used for a picture and you know as well as I do that nobody will ever come back with the answer "10mm!"

BR,

Richard.
 
Richard,

I agree that diffraction is going a bit off topic - I only mentioned because an earlier poster said that the lens could/should be stopped right down to maximise DOF, I just pointed out that this isn't normally a good idea.

I accept that some people may think that f/number and aperture are the same thing but I think that most people know better. I know of a few knowledgable wedding photographers who shoot with a 10 or 12mm aperture whenever they can, to get consistent DOF in their shots. the f/number they use to achieve that could be almost anything, they think in terms of aperture because it's meaningful, f numbers aren't.

I've tried to explain the concepts of diffraction limitation and f numbers -v- apertures in the least technical way possible. I'm not an optical physicist, I never got beyond A level physics and have no wish to turn a practical subject into a theoretical one - but it's impossible IMO to separate practical understanding from an understanding of the principles that governs it.
 
V8burble said:
DM got there with the link before me LOL.

Needless to say... Focal length/Aperture/Distance to subject are the three variables (or a constant if using a prime lens)
Click to expand...

That is the DOF link I always use. However, there are not "THREE" variables in the determination of Depth of Field but, "FOUR"!

The fourth variable which is often either forgotten or misunderstood is the "Circle of Confusion". That is a technical term for the very simple idea of how much blur will you accept in your image.

Widipedia definition
http://en.wikipedia.org/wiki/Circle_of_confusion
"To calculate a camera's depth of field (“DoF”), one needs to know how large a circle of confusion can be considered to be an acceptable focus. The maximum acceptable diameter of such a circle of confusion is known as the maximum permissible circle of confusion, the circle of confusion diameter limit, or the circle of confusion criterion, but is often incorrectly called simply the circle of confusion."

This is determined by the relative magnification required from any original image (whether that be a negative or a digital sensor capture).

Obviously, a smaller original capture; say on a 1.6x sensor will need to be enlarged more than the equivalent capture on a full-frame sensor (or negative). Therefore the smaller image needs to be in sharper focus than a larger image.

This is why in the Depth of Field Calculator < http://www.dofmaster.com/dofjs.html > there is a variable for "camera, film format, or circle of confusion"

As an example, using a 200mm lens at f/4 with your focus at 5 meters; the depth of field will be .09 meter for a 1.6x camera and .14 meter for a full frame camera. The full frame image will not need to be enlarged as greatly as the 1.6x image so there is greater depth of field.
 
rpcrowe said:
"The maximum acceptable diameter of such a circle of confusion is known as the maximum permissible circle of confusion, the circle of confusion diameter limit, or the circle of confusion criterion, but is often incorrectly called simply the circle of confusion."
Click to expand...

That is a masterpiece of utterly pointless garbage, written by somebody keen to show off their knowledge rather than to inform. Those people that understand depth of field should concentrate on making what is essentially a simple concept into one that is readily understood in a meaningful, practical way.

Richard.
 
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