Depth of Field (DOF)

Hey, another photography blog tip.

Happy James!?!?!?  🙂

From here on in (at least for this blog), I will refer to Depth of Field as DOF.  Shorter for me to type, don’t like it, too bad.  😛

So what exactly is DOF?

In optics, especially film and digital photography.  It’s the range of focus between the distances of objects.

DOF is determined by the subject to camera distance, the lens focal length, lens f-stop, format size (APO Sensor or Full Format) and what is known as the Circle of Confusion criterion.

I’m not going to get into the science of it,  this will just confuse  you.  You just need to know what impacts DOF.

Why is this important to know?

In most  some cases, agreeably, it is preferred to see the whole picture as sharp.  However, in other cases, it is preferable to have the main subject stand out, by having that object as sharp as possible and the background blurry.

This is mostly seen in Macro Photography and portraits as well.

How do I achieve such a photo?

1. Determine your subject. In this case, I have chosen my cable box’s remote control

2. Choose the right lens. I have chosen my 28-70mm F2.8

3. Position the camera. Handhold, about 25cm away, zoomed in at 70mm.

4. Set the F-stop via the Aperature Priority or Manual, for the purpose of this blog, I have chosen Aperature Priority and have used F22, F11, F5.6 and F2.8 (note: the higher the F number, the LONGER the shutter needs to stay open, especially in low light, unless you are shooting on a tripod, use a flash).

5. Decide whether you want to shoot with manual or automatic focus.  I have chosen to set my Nikon D200 on automatic continuous focus.

6. Shoot.

The next few photos will show you a look and which F-stop to choose for your DOF photos.  Click the pictures below for a larger view.

2010-08-14_17-19-10 This was shot at F22 with flash, notice the sharpness over the whole remote?  This is great, if you want to do something like take a picture of the object to sell it.  It gives the greatest detail of the object overall.





2010-08-14_17-19-24 This was shot at F11.  If you can see, the top and the bottom halves of the remote are starting to fuzz a little.  The center are the VOL button is still sharp (the focal point may change in the next couple of photos,I am hand holding the camera after all.)





2010-08-14_17-19-38I shot this one at F5.6, you can definitely tell the the top and bottom ends of the remote are out of focus, making the VOL and CH buttons very clear.




2010-08-14_17-20-36 Now you can definitely tell that the center buttons are the main focus of this photo.  Shooting at F2.8 will give you a really shallow DOF.





Examples of DOF photos I have taken:





Of course these photos were taken with a DSLR camera.  It is rare that a point and shoot camera will have this type of function.  I do know that the Nikon Coolpix 5700, 8700 and 8800 did have the ability to control f-stop and shutter speeds (these models have been discontinued).  This  type of point and shoot camera is also known has a Bridge Camera.  Other companies do have their own, but again, I deal in Nikon.

Now get out there and shoot some photos…


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