Tuesday, May 15, 2012

F- Stop or Aperture, its way cool!

What the heck is an "F stop" and why is it important?  The f stop refers to the relative size of the aperture (opening in the lens) that allows light to enter the camera.  Understanding how to use a particular F stop will go a long way towards creating images that you desire.  Wikipedia has a wealthe of information of course, check out "aperture" there to see some good graphics.

F Stop = 29
 
F-4

F-2.8

Examine the 3 photos above and decide which one you like best.

Why did you choose your selection?

The flower is in focus and looks essentially the same.  The background changes with the f-stop, either more or less in focus.  If you like nice arched Japanese bridges maybe you chose the top one. If you are less interested in the bridge and love flowers, maybe the bottom one with the bridge out of focus is your pick.

You can choose to have areas of the image be in or out of focus.  The text in the photo above stands out against the soft back ground.  Remember a small number like 1.7 or 2.8 is a larger size aperture opening.  A large number like f-22 is a small size aperture opening. An f stop of 2.8 will allow a shallow depth of field as shown in the the image above.  You can use this quality to make the main subject stand out or for graphics like the use of  text above.

Many people can understand aperture if they compare it to the pupil of the eye.  It gets larger or smaller to adjust the light coming in.

I usually shoot with my camera on "A" for apeture preferred.  I choose the aperture or F-stop, the camera automatically chooses the appropriate shutter speed to allow enough light in for the image to be captured.


In the shot above the aperture was set at 2.8, a large aperture which allows a lot of light in the camera in a short time.  The shutter speed was 1/1250 of a second, which if faster that you can say the "f"word, as in f-stop! This fast shutter speed "freezes" the action, which is good for sports or moving objects.

Shooting at f-32, the smallest aperture on the lens, the camera selected 1/3 or .333 of a second, fairly slow.  I used a tripod to make sure the camera was steady.  I had to lower the ISO to 100 so I could get a long exposure to soften the water.  This effect is often used for moving water, check out any calendar or greeting card with soft white water between rocks, probably shot with a tripod and an f stop of F-22 or F-32 and a loooong exposure or shutter speed.

Selective focus means you choose what you want in focus and intentionally choose an f-stop to make other areas out of focus or "soft".

This is a handy tool for making portraits.
Unn Chan at graduation party, 2012

Yamada Sensei speaking at the graduation.

You can add emphasis to your subject by focusing on it and throwing the other areas out of focus by choosing the appropriate f- stop setting or aperture.   A lens with a very small number, such as the F-1.4 Minolta I used for these portraits above, costs about double of a similar lens with a 1.7 aperture.  

The results can be twice as impressive, thats why pro photographers buy "good glass".   They pay high dollar for the best quality lenses that allow the most light in with the most clarity and allows a very large aperture.  The larger the aperture the faster the shutter speed, so its vitally important for many aspects of photography such as low-light, action/sports, birds, travel, portraits and so on.  Its better to spend the extra money on one good "fast" lens than two mediocre lenses.

My 20-30 year old Minolta F-1.4 lens was used to hand hold shots at our favorite restaurant Bombay Blue in Iwamizawa.  Jimmy the owner, hosted Indian music (all Japanese musicians) and a special dinner.  Without flash, I shot these photos which give it a homey feel and was less distracting to the other guests.




I chose a tungsten settting for white balance (WB) on my digital camera so that the skin tones would be more accurate shooting with regular lights. 

White balance will be a future post, so stay tuned and remember to keep your lens clean and your batteries charged, you never know when Brad and Angelina may let you snap the first shots of their baby, giving you a million dollar photo shoot