Depth of field with a point-and-shoot camera

<p>Still pretty happy with my little Canon PowerShot, but it does have its limitations.</p>

<p>http://i1183.photobucket.com/albums/x462/sharriso/Layout1/IMG_0733.jpg</p>

<p>Depth of field used to be easy with film: put a lot of light on it and lower the f-stop. Looked through my camera's manual but nothing about depth of field.<br /> <br /> Does anyone have any tips to share?</p>

<p>Shawn Harrison<br>

El Lago, Texas</p>

 

<p>Odds are there is no adjustable aperture. :(</p>

 

<p>Not much can be done as the normal and wide focal length of the lens doesn't allow much if any out of focus. Using the long focus optical setting can reduce the DOF somewhat, although also the field of view. Also, you might try to see if manual focus is possible with your camera, and if so then set a focus point well before your subject in order to try to stimulate out of focus in the longer distances.</p>

<p>With my PowerShot A80 I got too much depth of field even when the lens was at longest focal length and aperture was wide open. In auto or program mode, such control is usually not possible. Plain backgrounds, such as walls or curtains, can help.<br>

As a matter of interest, in their early years 35mm cameras were hailed for their far greater depth of field than cameras of larger format. Good for landscapes and architecture and so on, but not good for portraits of the traditional kind.</p>

<p>P&S cameras generally have very small sensors, and therefore use very short focal lengths to get reasonable angles of view. And they almost never have lenses faster than f/2.8; sometimes not even that fast. Because of this, shallow DoF is not easy to get. If this really matters to you, it may be that your best option is to upgrade to a DSLR or a large-sensor mirrorless camera.</p>

<p>Or if you are saying that you can't get ENOUGH DoF from your P&S, well, at close focusing distances even a small sensor with a short focal length has its limits. If the camera allows manual control of the aperture, then your formula of putting a lot of light on it and stopping down is still valid. If the camera does not allow manual control, then go shopping for one that does.</p>

<p>Most P&S, certainly every Canon I've ever handled, have had other shooting modes besides Program and the green 'idiot rectangle'. Try shooting in aperture-priority mode, manually set the f-stop for what you wish, and the camera will choose an appropriate speed. Of course your d-of-f will not match a similar setting on a 'normal' SLR lens/camera combo, you will have to experiment to get the results you like.</p>

<p>[[Most P&S, certainly every Canon I've ever handled, have had other shooting modes besides Program and the green 'idiot rectangle']]<br /> <br /> The majority of point and shoots on the market, including Canon, have little to no control over aperture or shutter speed. At best you'll get a mode that will let you select ISO, WB, and drive mode.</p>

<p>By your comment, "Depth of field used to be easy with film: put a lot of light on it and lower the f-stop," the only logical conclusion is that you are trying to <em>increase</em> the depth of field. (Because to decrease the depth of field, you use a larger aperture, which means a smaller number f-stop, and which therefore requires <em>less</em> light, all else being equal.)</p>

<p>But that is fairly odd: the common digital point-and-shoots, including your Canon SD780 IS, mostly use "1/2.3-inch" sensors which have about 5 stops more depth of field than 35mm film (or "full-frame" digital) does, all else being equal. So even if the camera is shooting at f/3.2 (the maximum aperture on yours), the depth of field is about what you'd get with 35mm film at f/18.</p>

<p>If you're indeed not getting enough depth of field, and you're confident that the camera is focusing where you want it to, try a 'landscape' mode or something like that, if your camera has it; I'm not sure what they all mean on the 780, but you might try "Digital Macro" or (with a tripod!) "Long Shutter". Many compact digitals today, including yours, lack an aperture-priority (or manual exposure) mode, but for those who have one, try the smallest aperture (usually f/8).</p>

<p>If somehow you are trying to <em>decrease</em> the depth of field (which seems odd, not only in view of the "a lot of light" comment, but also because most of your sample is out of focus), then forget it: with the tiny sensors on compact digitals, you're just going to have a lot of depth of field. Even a compact with a somewhat-larger "1/1.7-inch" sensor and an f/2 maximum aperture still gives you about the depth of field of 35mm film at f/8.</p>

<p>There are many Powershot models and types. Some do allow partial or full manual control (e.g. the G series). That said, tiny-format cameras have very little usable aperture range. My G11's apertures range between f/2.8 and f/8. Within this range, anything smaller than f/4 suffers noticeably from diffraction blur. Therefore my usable aperture range tends to be from f/2.8 to f/4. These apertures correspond to f/11 and f/16 on a full frame (24x36mm) camera, so there's not much capability for selective focus. I've accepted that depth of field is usually a useless concept in this format. If you want selective focus, you probably need a larger format camera -- at least an APS-C dSLR.</p>

<p>Thanks for the replies. Good discussion and reminders of some stuff I forgot. (Polite way of saying I just got re-educated.) I will try again using your suggestions.</p>

<p>And my bad about lower f-stop. Should have said smaller aperture.</p>

<p>I forgot how to add a picture in this forum. Should I insert the Photobucket Direct Link?</p>

<p>Snawn</p>

<p>You only powershot option if you want to play with DOF is the G1 X which has a sensor only just slightly smaller than APS-C. The lens isn't particularly fast (f2.8 to f5.8), but you'll still get shallower DOF then a small sensor camera with a faster lens (and most of them don't even have a faster lens).</p>

I looked at your picture and clearly the camera is

focusing on the object in the scene that is closest

to the camera. That's also how my point and

shoot operates (Nikon Coolpix) when the focusing

mode is set to "auto". You can override this by

choosing a manual mode that allows you to select

which area in the scene the camera should lock

focus on. If the camera had focused on the

central car of the group, my guess is that all 3 cars

would have been in focus, and not just the first.

<p>I've been able to get great DOF with the several Canon Powershot cameras that I own or have owned, using f/8.<br /> <br />Here's a shot I took a while ago with a Powershot S5:<br /> <img src="http://img.photobucket.com/albums/v409/railfan/PowershotDOF.jpg" alt="" /></p>

<p>I have the Canon S95 as my P&S companion when carrying a DSLR is impossible or impractical. I chose it because it shoots raw, has a fast aperture (f/2, although variable across zoom range), and allows manual settings, as well as Av, Tv, etc. It also allows for manual focusing, depending on how you set it up. Exposure control, etc are all possible. Very nice for a P&S, but not inexpensive.</p>

 

<p>Enjoyed reading the comments. It was cloudy and no sun this afternoon, but I experimented with my Canon a little anyway. Had it for three or four years, I think, and thought I knew how to use it. You guys got me to try harder -- tested some of the suggestions here. I will try to post some of the pictures.</p>