How to focus right between 4f subject and everything behind

[Crost_10D]

Hi everybody.
Just got my 10D from Gateway.... LLLoove it............
I've got 28-135mm IS Canon lens and now.....
I would like to ask you, how in the world I can take picture and have in focus everything the front subject and everything that's going to be behind. I've tryed different modes (A-dep included) and couldn't get sutisfactory results....
Thanks for your participation

[timmyquest]

you mean like this?

http://www.antiwall.com/Pictures/tigger.jpg

Your post is honestly a little confusing.

[RichardtheSane]

You need to use Av mode, and set the aperture as high as you can get.
This will increase your Depth of Field (DOF).

What sort of subject are you trying to photograph?

[PaulB]

Richard means high f number = small aperture = increased DoF.
Closer subject is you need increasingly smaller apertures to get a deep DoF.

[Crost_10D]

Yes like that picture... But that cat's picture was taken to close...
I mean like picture of (for example) a lot of people and background.
You see, when I'm changing my aperture to high like 8, 16, 22 then my picture comes out dark and what should I do with it. I changed shutter speed it still to dark or out of focus the whole pic. Should I use flash light? ( Cause I was trying all that at home inside my living room and I was trying to catch the chair the table and the wall and the table in focus, but the chair and the wall out of focus?
Strange isn't it? Or may be everything is so close to the camera, but shouldn't be cause it's more than 2 feet from a camera........
??

[WyzMan]

I'm guessing now but think that Crost_10D may be referring to using the 10D in full auto mode with all 7 AF points active. If this is the case, he/she may be pointing to a situation like this ....

Group of people, most of the focus points miss the subjects, focus obtained on a picture on the wall behind them.

I tend to have only the centre (yup - I'm English - not centER!), AF point active and compose that way. Focus centrally on the subject and if need be move off centre with the shutter release still half pressed - when composition is fine and dandy - press the release home.

Alan

[timmyquest]

Yes like that picture... But that cat's picture was taken to close...
I mean like picture of (for example) a lot of people and background.
You see, when I'm changing my aperture to high like 8, 16, 22 then my picture comes out dark and what should I do with it. I changed shutter speed it still to dark or out of focus the whole pic. Should I use flash light? ( Cause I was trying all that at home inside my living room and I was trying to catch the chair the table and the wall and the table in focus, but the chair and the wall out of focus?
Strange isn't it? Or may be everything is so close to the camera, but shouldn't be cause it's more than 2 feet from a camera........
??

A smaller apature (8 is smaller then 4) will give you less light, and it will make more of the picture come into focus. That picture was taken with my apature wide open. If you want everything in focus then you'll need to close the apature.

To adjust for the lack of light that a small apature allows you can turn the ISO up, use more light (obviously) or a longer shutter speed.

[scottbergerphoto]

I understand you to be asking, How can I get the subject and everything behind it in focus and nothing in front of it in focus. The difficulty answering the question you are asking lies in large part on understanding Depth of Field. When you focus on a subject, an area in front of the subject and behind the subject will be in focus. That's the depth of field. It is divided 1/3 in front of the subject and 2/3 behind. It can be on the order of inches or very large such as with landscapes. The smaller the aperture(larger f stop number) the larger the depth of field and vice versa. So technically, if you want to have the subject and everything behind it in focus, you would have to choose a small aperture f/16, f/22; use a depth of field calculator to determine the dimensions of the depth of field for the lens you are using,and focus 1/3 of the distance in back of the front most object you want in focus.
If anyone has a more elegant solution please feel free to educate me.
Scott

[Crost_10D]

I'm guessing now but think that Crost_10D may be referring to using the 10D in full auto mode with all 7 AF points active. If this is the case, he/she may be pointing to a situation like this ....

Group of people, most of the focus points miss the subjects, focus obtained on a picture on the wall behind them.

I tend to have only the centre (yup - I'm English - not centER!), AF point active and compose that way. Focus centrally on the subject and if need be move off centre with the shutter release still half pressed - when composition is fine and dandy - press the release home.

Alan

Well, I thought I said that I was using A-DEP

[defordphoto]

Even with the smallest f-stop there is a limitation to DOF. You cannot, for example, focus on a bug at 6 inches and infinity.

[Pekka]

Yes like that picture... But that cat's picture was taken to close...
I mean like picture of (for example) a lot of people and background.
You see, when I'm changing my aperture to high like 8, 16, 22 then my picture comes out dark and what should I do with it. I changed shutter speed it still to dark or out of focus the whole pic. Should I use flash light? ( Cause I was trying all that at home inside my living room and I was trying to catch the chair the table and the wall and the table in focus, but the chair and the wall out of focus?
Strange isn't it? Or may be everything is so close to the camera, but shouldn't be cause it's more than 2 feet from a camera........
??

Sorry if this is old news for you, but just in case:

DoF (Depth of Field) means a "box" of acceptable sharpness, and inside that box focus point is the only actually sharp plane. If you have subject that is 3 meters deep and your DoF is 3 meters then you will have to focus to the middle of the object so that it is "covered" by the DoF.

Relation between aperture, focal lenght and distance is what you have to get familar with if you want to have control over your camera, so that your results get closer to what you wished.

Closing aperture (bigger f number) means getting less light in (darker) from smaller hole, resulting in longer/deeper DoF

Opening aperture (smaller f number) means getting more light in (brighter) from larger hole, resulting in shallower/shorter DoF.

Zooming in (going towards tele range) means DoF gets shallower. Zooming out (going towards wide angle) means DoF gets deeper.

Moving closer to subject (focus point distance is near) means DoF gets shallower. Moving further from subject (focus point distance is far) means DoF gets deeper.

How to use this info in practical situations? First you need to have some approximate data in your mind: how is DoF when I have 100mm at 2/5/10 meters? What about 50mm at 2/5/10 meters? What about 20mm at 2/5/10 meters? If you have no idea how the DoF actually IS you will miss a lot of shots - this really is exact science (DoF can not be fooled) but it is generally enough if you have in your mind some vague idea that

17mm f/2.8 at 2m gives you 170cm of DoF.
20mm f/2.8 at 2m gives you 110cm of DoF.
35mm f/2.8 at 2m gives you 40cm of DoF.
50mm f/2.8 at 2m gives you 20cm of DoF.
100mm f/2.8 at 2m gives you 10cm of DoF.
200mm f/2.8 at 2m gives you less than 1cm of DoF.

You don't need to know the exact figures. Just estimation - like 35mm at 2.8 covers "one human head" nicely from two meters. As you see from the list that when you go wider, the DoF gets drastically deeper. Notice that that change is not even between focal lenghts. So small change in focal lenght does a lot the wider you go.

As you see with f/2.8 you'd need to use 20mm to cover DoF worth of one armchair from 2m :)

The aperture change is more "effective" in centimeters when you go towards wider angle lenses.

17mm f/5.6 at 2m gives you 6.5m of DoF.
20mm f/5.6 at 2m gives you 3m of DoF.
35mm f/5.6 at 2m gives you 70cm of DoF.
50mm f/5.6 at 2m gives you 30cm of DoF.
100mm f/5.6 at 2m gives you 8cm of DoF.
200mm f/5.6 at 2m gives you 2cm of DoF.

17mm f/11 at 2m gives you 0.8m to infinity of DoF.
20mm f/11 at 2m gives you 1m to infinity of DoF.
35mm f/11 at 2m gives you 155cm of DoF.
50mm f/11 at 2m gives you 70cm of DoF.
100mm f/11 at 2m gives you 17cm of DoF.
200mm f/11 at 2m gives you 4cm of DoF.

Use http://dfleming.ameranet.com/dofjs.html for browsing 10D DoF data.

The dilemma of daily SLR photography is that when you need to have more in focus, you'll get less light in. To fight this you have to either:

- slow down shutter speed
- use flash (which gets 'weaker' when you set f number bigger)
- raise ISO
- move away from subject
- use wider lens

Or any combination of above. There is simply no way out of it.

Of course when you shoot people you can ask them to move into tighter position, or when you shoot a jewelry collection you can arrange them so that they fall in DoF. You can do a lot by changing the camera angle and your shooting position.

Hope this was of any help to you.

[Tom W]

Crost_10D,

Welcome!

You're looking for a lot of knowledge - I recommend leafing some of the articles at this site:

http://www.luminous-landscape.com/tutorials/index.shtml

Also, you may wish to get hold of a good general photography book, such as "National Geographic Photography Field Guide" which has some very good information and illustrations to help explain the relationships between aperture, shutter speed, available light, and depth-of-field. I have that book and it is good. I still use it occasionally.

There's a lot of pieces to the puzzle that you need, and its hard to put them all together in a forum.

[robertwgross]

Even with the smallest f-stop there is a limitation to DOF. You cannot, for example, focus on a bug at 6 inches and infinity.

Yes, but at f/32, you can get a hell of a lot into focus.

I shoot landscapes where I have flowers in the foreground (at a few feet) and forest in the background (way out). I cheat. I use slow film. Too bad my digital Canon does not go lower than ISO 100.

---Bob Gross---

[defordphoto]

Very true Bob. Yeah. I'd love to have ISO50 or heaven forbid; 25! I used to love shooting ASA25 film...

[robertwgross]

That is why I still keep my Canon film camera loaded up with Velvia 50.

---Bob Gross---

[defordphoto]

Even the best of actions cannot replicate Velvia.

Yet.

[ijohnson]

Does anyone have a can of worms that has just been opened? I want to try some before I buy my own.

The ability to explain f-stop and depth of field should be left to the VERY few that can communicate it without adding to the confusion. Only I know what a higher f-stop is in my own mind, I have never, EVER communicated it with any luck.

Please refer to photography primers available on-line or, god forbid, the following page entitled, "A Tedious Explanation of the f/stop", which can be found at http://www.uscoles.com/fstop.htm

This will, at the very least, make it clear in your own mind. Just don't ever try to verbalize it.

[figment]

Focus Pocus:
http://www.outsight.com/hyperfocal.html#dof

[Tom W]

The ability to explain f-stop and depth of field should be left to the VERY few that can communicate it without adding to the confusion. Only I know what a higher f-stop is in my own mind, I have never, EVER communicated it with any luck.

I'm with you - I've got this mental picture of f-stops and depth-of-field and rulers at 30-degree angles ( :) ), and all, but I would be hard pressed to describe it verbally. Then when you throw in shutter speed and ISO and exposure, I am resorted to pointing to internet links. :)
[/quote]

[ilya]

Pekka's post is pretty comprehensive.

[robertwgross]

I'm with you - I've got this mental picture of f-stops and depth-of-field and rulers at 30-degree angles ( :) ), and all, but I would be hard pressed to describe it verbally. Then when you throw in shutter speed and ISO and exposure, I am resorted to pointing to internet links. :)


There are many good photographers here who simply *know* what they are doing with settings. They know it, and they get good results. Fine.

However, often it has been stated that you never *really know* your subject until you can teach it successfully.

Well, there is a friend of mine who is a nice person, and she has a Canon film Rebel. So help me, she cannot take it off the Green Box setting. She really does not understand cameras, f-stops, shutter speeds, ISO, or anything else that has numbers in it. I saw her trying to line up a nature shot, and I simply asked her what she was trying to do with Depth of Field. All I got for an answer was a blank stare.

So, I tried to offer my assistance. I thought that I could explain the various settings interactions to her, and how to get a wide DOF as compared to a shallow one. Nope. She did not want to hear about it. The Green Box is fine. So I dropped the subject.

I tried to explain flash Guide Numbers one time. Nope. I got as far as "divide that number by the f-stop ..." and she choked on that. Some folks just don't want to learn. <sigh>

---Bob Gross---

[Tom W]

I have to admit that I've used the "green box" on my Elan - twice. I haven't tried any of the modes with the little pictures on them. I grew up on the FT - just having a match-needle meter teaches at least the relationship between aperture and shutter speed. And the fact that the film speed dial is simply a mechanical "repositioning" of the shutter speed dial on the FT does much to introduce that relationship as well (unless one forgets to set the film speed - the FT is pre-DX).

It just stands to reason that I should be setting either the shutter, the aperture, or both by myself. I'm especially happy that I'll soon be able to set the ISO as well.

I'll admit that I might be a little better at explaining things that I might let on, but I'm also a very lazy person sometimes - its much easier to point to a link. Plus, I have a way with words where I sometimes say things in a very convoluted way. I don't want to add to the confusion.

And besides, I'm really not an expert - and I don't even play one on the internet. I have much to learn. :)

[defordphoto]

It can be very confusing yes. Links sometimes add to the confusion by overloading the member with too much information rather than just a simple explanation, especially someone new into photography. Many times just learning the terms is battle enough.

These forums offer practical experience and IMO some fo the best information on the Internet, properly filtered, of course. ;) No one here is going to let anyone go away from this forum with disinformation. If anyone leaves here without learning something, then it's their fault.

[Crost_10D]

Well, well, well.........
I really appreciate everybody’s answers….. I’m really amazed how many people taking a part in this forum. .. Really impressive. You know what I just realized is that nobody can learn in one day , neither in one week or one month; it comes with years of experience. It’s my second day I have my SLR and there’s so much to learn and create so, like I said, thanks to everybody for helpful links and advices, but I’m going to sleep and hopefully tomorrow I’ll wake up as a best photographer in the world :lol:
Thanks again
Crost_10D

[defordphoto]

Crost: Don't be afraid to experiment. You'll learn so much from just experimenting with different settings.

[Tom W]

Well, well, well.........
I really appreciate everybody’s answers….. I’m really amazed how many people taking a part in this forum. .. Really impressive. You know what I just realized is that nobody can learn in one day , neither in one week or one month; it comes with years of experience. It’s my second day I have my SLR and there’s so much to learn and create so, like I said, thanks to everybody for helpful links and advices, but I’m going to sleep and hopefully tomorrow I’ll wake up as a best photographer in the world :lol:
Thanks again
Crost_10D

You've already learned a lot today, just learning that there is a lot to learn. :)

Just take it one step at a time. The nice thing about digital is that you can experiment and see the results right away. You can set the camera to aperture priority (Av) and change the aperture, watch what the shutter speed does, and take the picture to see just how the depth-of-field changes as you vary the aperture.

Then you can set to shutter priority (Tv) and do the same, observing how fast shutters freeze motion and slower settings can blur motion but allow smaller aperture. Its all interrelated.

Play with it a little. Read a little, then play some more to try out what you've read. It really helps to experience it yourself, or at least it does for me.

I'm still in the learning stages myself.

Enjoy your new camera! :D

[figment]

This is how I understand the effect of lens aperture on depth of field...
http://figment.smugmug.com/photos/2043736-O.jpg
The top figure is a wide open lens with a close focus, the light from the image is concentrated to a spot at the plane of focus.
The bottom figure has the lens stopped down, the point of focus is further way and the light from the image is comming into the camera in a beam.

I may have somthing wrong here, but its the way I understand it.

(I whipped this picture out in about 2 minutes so don't pick on it too much :wink: )

[chris.bailey]

Thats not a bad way of visualising it and of course lenses magnify the effect and the greater the "magnification" the smaller the DOF, hence pinhole camera's having a huge DOF.

[EXA1a]

Even with the smallest f-stop there is a limitation to DOF. You cannot, for example, focus on a bug at 6 inches and infinity.

Yes, but at f/32, you can get a hell of a lot into focus.

---Bob Gross---

Apertures smaller than f11 will create visible diffraction=unsharpness, especially with small sensors. At f32, DOF looks great just because everything is soft and you don't have that really sharp area you'd get at below f11.
With macro this problem becomes even more serious because the effective aperture gets smaller with higher magnification ratios.

--Jens--