Photography and Depth of Field - Or How To Get Those Fuzzy Foreground/Backgrounds!

Happy Easter everyone!!!



I am one of those people who shoot mainly in Aperture Priority (Av) Mode. Av Mode allows me to set my aperture and the camera will adjust the shutter-speed (exposure) for me.  This is because I like to control the depth of field, or in other words, I sometimes want the background and/or foreground of my image to be out-of-focus (or have shallow depth-of-field). You can see what I mean in the image of the tree root above. The center of the image is in focus, but the foreground and background aren't. This is because I shot this with a "wide open" aperture.

If I had my camera in "idiot mode" the entire image probably would have been in focus, unless I used the portrait mode (which uses a wide aperture, but gives me no final control). Technically fine, but you lose control of your final image... In the portrait below you can see a subtle out-of- focus background. This brings attention to Imp's little mischievous face. I prefer the soft background.



I shoot in Av (aperture) priority mode 95% of the time. This setting allows me to preset my aperture and it will automatically adjust the shutter speed. I don't want to go into great detail today, but the larger your aperture, the smaller the number on your camera, and the less depth of field -dof- (in other words, your entire image will not be in focus).  

For example, see the photographs below of an old tennis ball I found out in the back yard.  I know, it is pretty gross. It is the cat's ball.

The first image is shot with a wide aperture (f/1.8,small number-large aperture, lots of light gets in the camera). Notice the foreground and background are blurred. I used my Canon EF 50mm f/1.8 II Camera Lens and had the aperture wide open so that lots of light got in (thus the fast 1/4000 second exposure). You have to be really careful when you shoot with your lens "wide open" because only a small part of the entire image will be in focus (shallow dof) so be sure to focus carefully and don't shake your camera.

The second and third images are shoot with smaller apertures (f/4.0 and f/6.3). Notice the smaller the aperture (larger numbers mean smaller apertures) more of the image is in focus and the exposure time is longer (because less light is getting into the camera through the lens).

Remember, I only set the aperture and ISO ("film" speed).  The camera automatically picked the exposure (amount of time the "film" is exposed to the light) for me. 

If you don't understand this, you have to go read Understanding Exposure: How to Shoot Great Photographs with a Film or Digital Camera (Updated Edition), it will change your photography life. I did not understand how "film" speed, exposure, and aperture all worked together until I read this book. Buy it or check it out from the library. This is the only photography (non-editing) book I use and I think it is the only one you have to buy to understand how to use your camera. If you want to be a "real" photographer and have some control of your images, please read this book!

BTW, if you are trying to capture quickly moving children in low light and don't want to use a flash, use a smaller aperture (or faster exposure) to make sure they are in focus and bump up your "film" speed.  There is no way you can shoot wide-open in dim light with moving kids.  They will be a complete blur.  Kind of like some of my days here!!!  :-)

The idiot modes on your camera can only get you so far, but once you understand how the camera takes photos, you can control your final images.  I don't think there is an idiot mode on my Canon Rebel XT that would be able to automatically capture this shot you see below.


By the way, I am so excited by the new Canon EOS Rebel T2i. It is not out yet, but I am so glad I have waited to get a new camera body. Well, I only waited because lack of funds, but still, I am glad I didn't get a new camera.  ;-)  I knew there was a reason my old camera was hanging on.  After all, it took the shots in this post!

My Rebel XT is still doing fine, but I will upgrade when this Canon T2i has been out for a while. It not only has excellent low light abilities (a must for this mom who hates using any type of flash), but it also has HD movie capabilities. Having a camera and movie camera combined sounds like this mom's dreams come true. If anyone has seen this camera I would love to hear about it! I hope it is as good as it sounds.

12 Comments:

Tammy Dunlap April 4, 2010 at 9:30 PM  

Thanks for the todays post! I will be getting some of those books of his soon!

Dani B April 4, 2010 at 9:49 PM  

This may prove to be the most useful piece of information I've received on the internet! I guess I need a different lens. Mine goes down to 3.5 and that's it. It's a pretty versatile lens, which is why I have it. I usually stay as far back from the subject and zoom in as close as I can to get a blurred background easily on the auto setting, but I can't wait to try this!! And I ALWAYS have trouble with motion in low light, so thank you!!!

Anji Johnston April 4, 2010 at 11:38 PM  

Such a helpful post - thank you! I never really use my camera on AV (I'm a big chicken when it comes to new settings!) but I will be trying this tomorrow. I really appreciate ALL your posts - they have made my 'photography' life so much easier!

CraftCrave April 5, 2010 at 10:02 AM  

Just a quick note to let you know that a link to this post will be placed on CraftCrave today [05 Apr 02:00pm GMT]. Thanks, Maria

Rebecca April 5, 2010 at 11:57 AM  

I'm still shooting with an XT too. So nice to meet you! :)

I continue to love your site.

Christie April 5, 2010 at 4:38 PM  

Ok?!? Where have you been all my photoshopping life? Your site is PERFECT for me! Found your link on Following In My Shoes.

Lorinda April 7, 2010 at 9:46 PM  

This answered my reason for being frustrated with my new canon digital rebel t1i. The lens it came with only goes to 3.5 so most of the photos are all or mostly in focus (unless I am very close to my subject and the background is distant). If I wanted that I would have spent a lot less for a point and shoot. I ordered the lens you recommended and I will be using the AV mode a lot more. Thanks Rita for the amazing tidbits. We are all grateful for the help!

Rita April 7, 2010 at 11:18 PM  

So cool I have some new readers here! Av mode is my favorite mode, and once you realize how easy it is to shoot in it you will get addicted, trying to find that amazing bokeh everywhere. Rita

Anonymous April 8, 2010 at 3:30 PM  

Thank you for your post, and I'm glad to hear that you are excited about a new camera. One thing about DSLR cameras with video capabilities that I heard from a professional photographer that the video feature is very difficult to operate because of having to adjust the focus. Make sure you really play with the camera and use it and see the results of the video capabilities to see if you like the results. If you don't, you would be better off to get a camera, like the Canon XSi without the video and then purchase a separate video camera you can fit in your camera bag. I hope that you find just what you are looking for!

photographyleeds April 17, 2010 at 2:14 AM  

Hi Rita, i love your blog!(-: I too use the 1.8 lens and tbh theres not much difference in terms of quality to the 1.4. Sure the 1.4's a slightly faster lens and will work better in lower light and will AF on a D60 for example. Apart from that i can't see many advantages of the 1.4. Personally, i have two 1.8's, one as a back up, and both cost less than the 1.4 lens..haha.

I've just ordered the 17-55 2.8 lens and next on my wish list is the 70-200 2.8.

Keep blogging!

Clare x
http://www.photographyleeds.co.uk

Keep blogging!

crystal November 20, 2010 at 8:46 PM  

i HAVE THE CANON t2I AND THE 17-85MM KIT LENS, THE APERTURE ONLY GOES DOWN TO f5.6?? :(
~Crystal Zabka PhotographY

Anonymous January 14, 2011 at 3:06 AM  

thank you.. I heard about your site when I asked about a watermark..I have a Canon 590..not a slr, but, the av will go to 2 and it has a great zoom lens..I am going to try this to get the bokeh look I have been trying to achieve. I will be using your site...and compensate you...still am trying to figure out how to get my signature on my photos, but, will read your instructions again. thank you for your generosity.