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View Full Version : having trouble understanding Aperture and Shutter



shatterspeed
01-21-2008, 03:48 PM
I recently bought a Fujifilm F31fd, which took 4 months of deciding cause' originally, I wanted to get the Canon Powershot SD850. I settled for the F31 upon seeing pros/consumer reviews mainly the F31 having the Aperture/Shutter priorities. I'm having trouble getting the concept between these 2 functions. Can anyone please explain the differences to me. When's the best time to use Aperture or Shutter? I also don't understand the f/2.8, f/6..or whatever. What are they?

DonSchap
01-21-2008, 04:07 PM
Along with that camera you bought ... you need to get your hands on a telltale book entitled:
(Click here => ) Understanding Exposure (http://www.amazon.com/Understanding-Exposure-Bryan-Peterson/dp/0817437126), by Bryan Peterson.

This tell-all book will impart a terrific understanding of the very question you ask ... and add other exciting aspects to the discussion, like "What is ISO?", "What makes for a good photographic composition?" and "What the heck is White Blance?"

Far more instructive than a two-second answer, you will learn more from this one book than you probably ever even thought to ask.

It's a winner ... Click on that link and get your answers.

ssil2000
01-21-2008, 04:41 PM
Along with that camera you bought ... you need to get your hands on a telltale book entitled:
(Click here => ) Understanding Exposure (http://www.amazon.com/Understanding-Exposure-Bryan-Peterson/dp/0817437126), by Bryan Peterson.

This tell-all book will impart a terrific understanding of the very question you ask ... and add other exciting aspects to the discussion, like "What is ISO?", "What makes for a good photographic composition?" and "What the heck is White Blance?"

Far more instructive than a two-second answer, you will learn more from this one book than you probably ever even thought to ask.

It's a winner ... Click on that link and get your answers.

couldnt agree more, great book, only one thing may be useful following this link (http://www.amazon.com/Understanding-Exposure-Photographs-Digital-Updated/dp/0817463003/ref=sr_1_1?ie=UTF8&s=books&qid=1200962378&sr=1-1) which has the updated edition for film & digital.

but a great book and really lets you see the difference as opposed to telling you what it is...

must have!

Sergio

Graystar
01-21-2008, 04:47 PM
Aperture Priority ? you set the aperture size and the camera determines the shutter speed.
Shutter Priority ? you set the shutter speed and the camera determines the aperture size.

Aperture - hole inside the lens that can be made large or small.
f/2.8, f/... ? indicates the aperture size. Larger numbers means smaller size.


Which mode you use depends on what you?re concerned about. If you want to take a picture of something that?s moving and what to make sure it isn?t blurry, then you would use Shutter Priority and set a fast shutter speed. The camera then sets the aperture for proper exposure. If you want to do something artistic and catch movement in your image (such as water in a stream) then use Shutter Priority and set a slow shutter speed.

If your concern is a blurry or a sharp background, then use Aperture Priority and set a large aperture (smallest number) for blurry backgrounds or a small aperture (largest number) so that your subject and the background is sharp. The camera will select the shutter speed for proper exposure.

It?s more complicated than that, and there?s the issue of running into limits of your camera while trying to get certain shots, but that should get you started.
________
NO2 VAPORIZER REVIEW (http://no2vaporizer.net)

griptape
01-21-2008, 07:20 PM
http://www.utata.org/g/techtata/aperturea.jpg

fotogmarc
01-22-2008, 04:22 AM
Here's a few online guides to help out with the basics.

http://www.hp.com/united-states/consumer/digital_photography/tours/controls/index_f.html

http://www.usa.canon.com/consumer/controller?act=MultiMiscPageAct&key=Learning_Station&fcategoryid=2533
Then click on: 'enjoy digital SLR cameras'

Hope these help

TDI-Guy
01-22-2008, 10:38 AM
try this, it's an interactive camera

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

shatterspeed
02-01-2008, 10:34 AM
DonSchap, ssil2000; thanks for the info. I'll try to look it at the local bookstore since I don't have a credit card.

Graystar, TDI-Guy, fotogmarc, griptape; thanks so much for explaining things in a manner I could comprehend. before I made this thread, I looked it up on Wikipedia and I couldn't understand what 3 stops faster than mean. I'm more of a visual-learner and thanks to that image, I finally understood what those f/x are.

the Shutter mode is for moving subject(s) as you stated. but since the F31fd doesn't have O.I.S, would that still help capture the subject in an acceptable (if not great) result? also, would raising the ISO help?

DonSchap
02-01-2008, 10:57 AM
Traditionally ... shutter speed for a standard image:

1/60 sec will eliminate camera shake. This is usually your base flash sync speed also. Consider this the "normal light" setting.

Not adjusting the aperture or ISO ...

1/125 sec makes movement tolerance a bit better, but you begin to cut down your light by one f/ stop from the prior 1/60th setting.

1/250 sec will usually freeze someone walking at normal speed, light is cut by 2 f/stops from the original 1/60 setting.

1/500 sec will will usually freeze someone walking at fast speed, your light is cut by 3 f/stops.

1/800 sec will stop a runner light is cut by 3.5 f/stops

1/1000 sec with stop a helicopter rotor light is cut by 4 f/stops


ISO will compensate for these light losses, up to a point.

This is pretty basic stuff, so indulge me, here. For example:

Let's say the "Original" camera settings (in S-mode) were 1/60th and an ISO of 400. In this mode, the camera chooses whatever it senses the proper aperture would be for the exposure (say it decides on f/5.6).

You snap the shot and immediately notice you are getting some movement blur ... so you increase shutter speed to 1/125th. The aperture adjusts to f/4 and you still are at ISO-400. You snap again ... still, some blur.

You push the shutter-speed to 1/250 ... but the lens has run out of aperture correction. THe shot has lost one-f/stop of light, because the lens' aperture cannot correct for the speed change. You want that light back! This is where you adjust the ISO up to the next setting, which, in this case, is ISO-800.

You snap again ... there is still some annoying level of blur. You go to 1/500th ... swearing and cursing, as the lens still is at its maxiumum aperture of f/4. Yep, you reach for the ISO adjustment and step it up, one more time, to ISO-1600. You are now, more than likely, at the camera's last correction available, that is without switching lenses. The exposure level has been maintained throughout this exercise, except the image's NOISE level has gone up. How bad? Depends on the image, to be honest. But, hey, the blur should be gone!

I hope this helps a little. :) Try it out.

Graystar
02-01-2008, 11:36 AM
the Shutter mode is for moving subject(s) as you stated. but since the F31fd doesn't have O.I.S, would that still help capture the subject in an acceptable (if not great) result? also, would raising the ISO help?

The purpose of OIS (or any image stabilizing system) is to deal with YOUR movement...not the movement of your subject. So it?s best to consider separately the blur cause by your movement and blur cause by the subject's movements.

Fast shutter speeds will eliminate blurring cause by both subject and photographer movements. When you need to stop the action, you must use a fast shutter speed. If you can't get a fast enough shutter speed then increasing the ISO should allow you increase shutter speed. The price of increased ISO is increased noise in your image.

Photographer movements will blur the entire image from edge to edge. OIS helps to reduce this blurring.

Subject movements will cause blurriness of the subject while leaving the background sharp. In this case OIS can?t do anything for you. The blurriness may be desirable, as in the case of a waterfall, or undesirable, as in the case of sports events. This is where you take artistic license and adjust shutter speed as you see fit.
________
FORD SYNC (http://www.ford-wiki.com/wiki/Ford_Sync)