Aperture/Shutter Speed Relationship

[Camelracer]

Whilst looking through some articles on the web regarding the above I found a very easy to understand explanation of the relationship.

http://www.pbase.com/wlhuber/image/41450051

[Sven]

Adding to this great resource, I have found this site helpful in understanding the realtionships between all factors. It's an interactive site that lets you change the variables and shows you the results.

http://www.photonhead.com/simcam/

Sven

[Hannah]

Wow - these really help - thanks, guys!

[lee.cook]

Hello,

The shutter and aperture both control how much light hits the image sensor, aperture also has a relationship with Depth of Field.

Depth of Field is how much is sharp/in-focus from front to back of the image, such as a landscape image.

A high f-number (f/2.8) will decrease your DOF, and a low f-number (f/11) will increase it.

f/2.8 - lower dof
f/4.5 - low dof
f/11 - increased dof
f/22 - increased dof

Depth of field video here -
http://youtube.com/watch?v=uzedefUXARE
Shutter video here -
http://youtube.com/watch?v=g9s4M1jKhwU&mode=related&search=
Aperture video here -
http://youtube.com/watch?v=g5310BnZo8A&mode=related&search=

Also, you might want to learn about ASA/ISO film speed, which is explained on the http://www.photonhead.com/simcam/ website.

Example: Aperture f/2.8 - 1/500 sec
http://www.photonhead.com/simcam/images/basicexposure/basicexposure_100ASA_f2.8_500.jpg

Example: Aperture f/22 - 1/8 sec
http://www.photonhead.com/simcam/images/basicexposure/basicexposure_100ASA_f22_8.jpg

Notice how the image with f/22 has alot more depth of field from front to back of the image, the image is alot sharper and clearer than the image with f/2.8 - but this isnt always the effect you want, sometimes you would want to isolate your subject(the couple) from the background by using a higher f-number, which would blur the background whilst keeping your subject in clear focus.

Hope I have helped :) please correct me guys if I said anything wrong hehe!

[MatsP]

Lee,

Yes, that's right.

The part you didn't mention is the relationship between subject movement and the shutter speed. A fast shutter (1/1000 or faster) will "freeze" the movement completely, whilst a slow shutter (1/30 or slower) will make any movement in the subject very visible (by blurring the subject). Inbetween, there will be more or less noticable blurring depending on the amount of movement in the subject.

It's also more difficult to hold the camera still for the longer shutter periods. Holding the camera still is usually a function of 1/x where x is the focal length in millimeter (so a 50mm lens requires 1/50 second or faster, a 200mm telephoto lens requires 1/200).

The blurring or lack thereof can be used in for example action photos. If you take a photo [Lee, you have a good oppurtunity right this week at the TT!] of a motorcyclist riding fast[1] on the road at 1/2000, you should see the wheels standing still, whilst if you use a 1/200 time, the wheels will have some movement - and if you "follow" the rider, you'll also get a nice blurred background. This is called panning. For other "action" photography,
the timing varies a little bit - experimenting a bit is the only way to get there.

[1] It's easier to take photos of the a motorcycle rider when the are going a bit slower than 100mph - at least if you don't have a long lens and stand quite a bit away. So finding a corner is a good way to get nice motorcycle racing photos.

--
Mats

[PhotographyBB.com]

Great information everyone! If anybody would like to check it out, in my free downloadable ezine (http://www.photographyBB.com/magazine) , issue 1 has a tutorial on mastering aperture, and issue 2 goes into exposure/shutter speeds.

I hope it can help to shed some light on things too, in addition to all the great resources that you have posted above.

Dave