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DPChallenge Forums >> Tips, Tricks, and Q&A >> Depth of field...
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 07/05/2005 03:11:42 PM · #1
When I first got into photography (about a year ago), I had a Sony DSC-F828. It was a great camera. I usually had everything set to fully automatic (aperature, iso, shutter speed, focus, etc.). With everything set to automatic, it wasn't hard for me to take pictures where the foreground and background were both in focus...I guess that is called depth of field, right?

A few months ago, I bought a Canon 20D. I wanted to take the next step and move into the DSLR world. However, ever since I got the new camera, I have not been able to take a picture where the foreground and background are in focus...is that called infinite focus??? Here are two great examples of pictures, on DPC, that have both the foreground and background in focus:

1. //dpchallenge.com/image.php?IMAGE_ID=81069
2. //dpchallenge.com/image.php?IMAGE_ID=185753

If anyone knows how to do this, please let me know. I have some great photo ideas, but they require an all-around sharp focus. Thanks a lot.
 07/05/2005 03:14:25 PM · #2
Easiest thing to do is use high F number. Both pics you posted are taken at F16 is you noted. Wide-angle lens with F16 or higher will give you very deep depth of field.
 07/05/2005 03:15:18 PM · #3
Both of those are shot at f16. It's the aperature on the most part that controls the DOF. The higher the number the more DOF. The downside is that with higher numbers comes smaller openings therefore less light getting to the sensor. To compensate you have to use slower shutter speeds.
 07/05/2005 03:17:10 PM · #4
DOF is controlled by using your aperture to get a longer or shorter shutter. Read up on exposure to figure out more, but basically higher aperture and longer shutter = deep DOF. Low aperture, fast shutter = shallow DOF.

Non-DSLR cameras are notorious for having a deep DOF, a DSLR gives you much more flexability and that is what you are seeing.

Message edited by author 2005-07-05 15:17:58.
 07/05/2005 03:17:33 PM · #5
Both of the posted comments, above, help. The only question I have then is what should the camera focus on? I actually tried setting the camera to a higher aperature number, but the automatic focus kept focusing on one one particular area. Do you HAVE to use manual focus?
 07/05/2005 03:17:35 PM · #6
You need to use your apeture to achieve the results you are seeking.

You can do this using programme mode or apeture priority mode on the 20D, refer to your manual for how to do this.

The larger the f number, the smaller the apeture and the deeper the depth of field. ie, f2.8 is very shallow dof, f22 gives deeper dof.

Hope this helps,

Steve
 07/05/2005 03:17:39 PM · #7
Originally posted by chafer:
When I first got into photography (about a year ago), I had a Sony DSC-F828. It was a great camera. I usually had everything set to fully automatic (aperature, iso, shutter speed, focus, etc.). With everything set to automatic, it wasn't hard for me to take pictures where the foreground and background were both in focus...I guess that is called depth of field, right?

A few months ago, I bought a Canon 20D. I wanted to take the next step and move into the DSLR world. However, ever since I got the new camera, I have not been able to take a picture where the foreground and background are in focus...is that called infinite focus??? Here are two great examples of pictures, on DPC, that have both the foreground and background in focus:

1. //dpchallenge.com/image.php?IMAGE_ID=81069
2. //dpchallenge.com/image.php?IMAGE_ID=185753

If anyone knows how to do this, please let me know. I have some great photo ideas, but they require an all-around sharp focus. Thanks a lot.


question 1: That would be DEEP depth of field.
question 2: infinite focus is where you means you are maximizing your depth of field for the given apearture you are set at.

depth of field is mostly controled by the aperature or f/#
f/2.8 is very shallow where f/16 is deep.
07/05/2005 03:17:54 PM · #8
IN adidtion to what guarawa posted, also note that both were taken at wide angle. The first at 12mm, the second with an 18-70 nikkor (at the wider end judging by the perspective). A short focal length and small aperture (f/16 in both cases) are what you need. You also need to focus at what is called the hyperfocal distance to maximize the DoF.

Edit:
Experiment with this online calculator, which can teach you a lot about what DoF you will get with various combinations of focal length and aperture. It also calculates the hyperfocal distance for any combination of focal length and aperture, for a given camera.

Message edited by author 2005-07-05 15:20:53.
 07/05/2005 03:19:35 PM · #9
it all depends on your composition, select the subject of the photo and camera will focus on that, then with large f-number, front and rear will also be in focus.

Steve
 07/05/2005 03:22:01 PM · #10
If you are taking a landscape and want a deep DOF, rather then focus on the farthest thing in the scene, focus on something in about the middle of the scene (AKA hyperfocal distance) to get the most out of your DOF band.
07/05/2005 03:23:15 PM · #11
Originally posted by chafer:
Both of the posted comments, above, help. The only question I have then is what should the camera focus on? I actually tried setting the camera to a higher aperature number, but the automatic focus kept focusing on one one particular area. Do you HAVE to use manual focus?

You can do different things at this point.
1) use the hyperfocal distance mehod as kirbic suggested. For this you will need to calculate the hyperfocal distance for your focal length and the aperture. You can find such a table on the net.
2) Easier way ? Focus on the closer subject and leave the rest to low aperture. You can do this by auto-focus or by manually focusing.
07/05/2005 03:24:17 PM · #12
Thanks a lot for all of your comments. Hopefully I can apply some of the techniques.
 07/05/2005 03:24:59 PM · #13
Originally posted by louddog:
If you are taking a landscape and want a deep DOF, rather then focus on the farthest thing in the scene, focus on something in about the middle of the scene (AKA hyperfocal distance) to get the most out of your DOF band.

I think this is a little mis-leading as hyper-focal distance is not defined that losely. I don't have a link to any specific formulae now, but hyper-focal distance depends on your focal length and your aperture and its a fixed number.
 07/05/2005 03:32:30 PM · #14
Perhaps try DOFmaster. It's on the net and can be found by searching.

If you're using a wide angle lens and wish to focus at or about the hyperfocal distance, you need a lens with a distance scale. A couple of hyperfocal distance examples: at 12mm and f11, HD is 0.68 m; at 12mm and f16, HD is 0.49m. In the former case, everything from 0.34m to infinity should be infocus, in the latter, everything from 0.24m to infinity.
 07/05/2005 03:32:42 PM · #15
Hi Chafer. I just migrated from F828 to 20D last week :) There is a setting on the 20D main dial called A-DEP. According to the Canon Litterature, this is supposed to give you the widest depth of field in any given situation. I havn't experimented yet though.

(Sidenote):I spoke to a nature photographer (Paul Salvado, Canon1D mkII) who shoots only in Apperture priority using the preview dof button, controlling his shutter speed with ISO according to what his desired dof requires.
07/05/2005 03:38:07 PM · #16
A ggod description of hyperfocal distance, with calculators, can be found at...
What is Hyperfocal Distance and Why Should I Care?


07/05/2005 03:44:40 PM · #17
Originally posted by gaurawa:
Originally posted by louddog:
If you are taking a landscape and want a deep DOF, rather then focus on the farthest thing in the scene, focus on something in about the middle of the scene (AKA hyperfocal distance) to get the most out of your DOF band.

I think this is a little mis-leading as hyper-focal distance is not defined that losely. I don't have a link to any specific formulae now, but hyper-focal distance depends on your focal length and your aperture and its a fixed number.


True, but as a rule of thumb focusing on something more towards the middle or even closer to you is going to be a much wiser choice then focusing on the farthest thing, as a lot of people do when they take a landscape photo.
07/25/2005 04:16:32 AM · #18
here's another useful online dof calculator
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