Canon 20D Question

[Jonathan Wienke]

Forget the green rectangle mode. The camera is not psychic, and cannot possibly satisfy everyone's photographic needs in an auto mode. You need to learn the relationship between aperture on depth of field. I have a spreadsheet you can use to calculate depth of field here. You'll have to enter the height of your camera sensor (15mm) and the vertical sensor resolution (2336). Once you've done that, enter the focal length of the lens you're using and the distance from camera to subject, and the spreadsheet will give you the DOF from f/1 to f/64. Use manual mode, and set the desired aperture from the spreadsheet.

[RobertJ]

You're going to have to start using Aperture Priority, (AV).  

What lens are you using?  

For starters, since you haven't learned about aperture/shutter speeds yet, if you're shooting your dogs in a controlled environment, with plenty of light, try setting your camera to AV mode, set the aperture anywhere from f/5.6 to f/11, and if you can't reach a fast enough shutter speed, set up more lights, or use a tripod.  If you're using flash, set the camera to Manual mode.  Don't be scared of the "M."  

You are holding a digital SLR, not a point and shoot.  Most importantly, you don't have to develop any film.  You have the freedom to experiment, and you should be able to learn very quickly by just playing around with different aperture and shutter speed combinations.  Have fun!

T-1000

[hhuxford]

T-1000, the lens I'm using is an 18-55mm.

I'll have to set something up in the garage w/out using the dogs and experiment a bit. I'll try *gulp* the "M" and see what happens too.

Thank you all for the tips and suggestions! That spreadsheet is neat!  

[howard smith]

I suggest you go to photo.net.  Look under the "What's new ... ?"  You should find an article on Field of View.  Dig into that and you will find a link to "Depth of Field and Digital" by Bob Atkins.  It is in the readers' repsonses section.  That will tekk what you need to know about DoF.

The main thing is:

"The depth of field is the range of distances reproduced in a print over which the image is not unacceptably less sharp than the sharpest part of the image".  [Emphasis on "in a print."]

This definition contains some important points.

First, DOF relates to a print or other reproduction of an image. It's NOT an intrinsic property of a lens. If you put a lens on an optical bench you can measure focal length, you can measure aperture, but you can't measure depth of field. Depth of field depends on some subjective factors which I'll discuss later.

Second, note the phrase "not unacceptably less sharp". All parts of an image which come from outside the focal plane of the lens are blurred to some extent. Only one plane is in focus. As you move away from that plane things get less sharp. The depth of field limits are where the loss of sharpness becomes unacceptable - to a "standard" observer.
 
Third, note the phrase "..not unacceptably less sharp than the sharpest part of the image...". This covers the case of a pinhole camera. Such a camera has a very, very large depth of field (almost, but not quite infinite). However none of the image is sharp. The depth of field is large because all the image is equally blurred!
 
An important thing to note is that depth of field is NOT what some people think it is, i.e. a well defined zone over which everything is in sharp focus. Some people seem to have the impression that an image has two zones. In focus and out of focus. In fact there is only one point (actually plane) in focus. Everything else is out of focus to some extent.

[hhuxford]

For those who have little patience with newbie, and possibly stupid, questions... please bypass this.

When I have my new Canon 20D on the basic zone, "fully automatic setting" (the green rectangle) I'm almost always coming up with a very, very shallow depth of field. I'm talking about maybe five inches if I'm lucky.

I'm trying to photograph my dogs in a "studio" type setting in my garage. They're on a table with a sheet as a backdrop. Sometimes their nose will be in perfect focus and the rest of the body slightly or completely out of focus or the flowers I have on the table with them, at their feet, will be in perfect focus but the dog's body, while they're laying down, about 5 inches behind the flowers, will be out of focus.

Am I missing something that I'm supposed to set or turn on the 20D, in the basic zone, that will give me a larger depth of field? (I don't feel competent enough yet to try the creative zone settings. Forgive me! I'm learning slowly!)

If it's something that just always happens with the fully automatic setting, what automatic basic zone setting should I use to get a larger depth of field while photographing my dogs in a "studio" type setting?

I hope I haven't totally used the wrong words for what I'm trying to explain.

Can someone with patience help me?

Thanks in advance!

[boku]

I understand your hesitance being new to this, but frankly, you have a DSLR camera and it requires more user knowhow than a point-and-shoot for predictable results.

To get predictable depth-of-field you have two choices: Aperture Priority or Manual. I know you didn't want to hear that, but that is the reality. Anything you do to get one of these "zones" to be tricked into whatever result you are after will avoid the ultimate reality that you must learn more about camera handling to be an effective photographer with a DSLR.

Sorry to deliver the bad news. My sig describes where I'm coming from.

[hhuxford]

*holding up hands*  Okay, okay! I'll get out my manual and start trying to learn to use the AP modes.

Next question about AP mode: If I set the camera for a particular f-stop and take a picture, will the camera keep that setting until I tell it differently or will I have to re-set the f-stop each time?

Thank you both very much for your patience!

[61Dynamic]

Next question about AP mode: If I set the camera for a particular f-stop and take a picture, will the camera keep that setting until I tell it differently or will I have to re-set the f-stop each time?

The camera will retain the aperture you set it to until you change it.

If you do not have enough light or you don't have the ISO set high enough the shutter speeds are probably going to dip down low. You'll then get blurry images for a entirely different reason; camera shake. I'm guessing since you kept getting such shallow DOF in full auto, there is not much light for you to work. This would explain why the camera opened up the aperture as much as possable to compensate.

Use some studio strobes or bounce a flash to get mor light on them dogs. If you can't do either, then increase the ISO.