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X-SOFT
10-20-2006, 01:20 PM
i have canon a710is, and i have aperture from 2.8 till 8.0

now i want to understand what doest aperture is, and what are those numbers mean.
and some tips where and when to use it (if i need it at all) from 2.8 till 8.0

so if someone can explain, i'd be glad.

ktixx
10-20-2006, 01:54 PM
the aperture is the hole that lets light into the camera. Here is what holds true to aperture:
The Larger the hole = Smaller f/#
The Smaller the hole - Larger f/#
The smaller the f/ the more light is let into the camera (faster shutter speed)
The large the f/ the less light is let into the camera (slower shutter speed)
The smaller the f/ the less DOF (Depth of Field) - I.E.: Blurry Backgrounds (bokeh)
The larger the f/ the more DOF - I.E.: Clearer Backrounds

Use Small f/ when you are in dark situations or for shots where you want to accentuate the foreground and blur out a messy background
Use larger f/ when you want a lot of your picture to be in focus.

The f/stop rating on your camera (2.8 to 4.8) is the minimum (widest) aperture you can get throughout the zoom. Meaning, at the widest your lens can get the largest aperture will be 2.8. You can set your camera so that at the widest your lens can get your aperture is 10 (not sure what your camera alows), but again, the largest aperture you can get is 2.8. The 4.8 signifies the largest aperture you can have while fully telephoto. Again, you can set your aperture for 10, 12, 14, etc. (again not sure what your camera alows) while telephoto, but the largest aperture you can get is 4.8.

That is a brief overview of aperture, if you want to know more i suggest googling it, I am sure there are plenty of articles out there on the subject.

Example: Low F/# (Shallow DOF)
http://i21.photobucket.com/albums/b255/Ktixx/FM%20Pictures/154.jpg
Notice that in the above example the tombstone is in focus, but the trees are not. I believe I used f/1.8 for this image

Example: High F/# (Larger DOF)
http://i21.photobucket.com/albums/b255/Ktixx/Big_Ben-1.jpg
Notice that in the above example the bottom of Big Ben, all the way to the top is in focus. I used a smaller aperture here (I think f/10 or f/13)

Hope this helps
Ken

Sintares
10-20-2006, 02:08 PM
Aperture is the size of the opening that lets light into the camera.

Aperture is referred to by fnumbers, where the smaller the number the larger the opening.

Each successive number in the f stop series halves the light let into the camera eg f2.8 stops down down f4 down to f5.6 down to f8

So f8 is 3 stops smaller than f2.8, and f8 thus lets in only 1/8 of the light that f2.8 would.

Each "stop" halves the light and doubles the time you would need to open the shutter to gain the same exposure.

Eg if at f2.8 you need to expose for 1/200 of a second , using f8 you would need to expose for 1/25s

Aperture is used mainly to control depth of field ie the amount in front of and behind the subject is acceptably in focus.

At f2.8 only a small zone around the subject would be in focus, while at f8 a larger zone would be.

Digicams because of their tiny sensors have very deep depth of fields, compared to slrs/dslrs, so unless you don't want a lot of depth of field its hardly a worry.

In other words taking a portrait (for example) with a dslr you can easily get the person in focus while the background has a nice blur, using a digicam both would tend to be in focus unless the background was much further back you used zoom etc

Artfully taken pictures of flowers etc also often need a small depth of field , to add focus to the flower and blur out the distracting background.

Conversly people using dslrs often curse the need to use a much smaller aperture if they actually need a lot of depth of field, especially tricky when taking macro pictures of bugs etc when a narrow depth of field can mean even a tiny bug is hard to get totally in focus.

JMK33
10-20-2006, 05:15 PM
I've been trying to figure this out on my camera...I have an Olympus Evolt E-500...and I still can't figure out how to change the aperature even after reading the manual...can anyone help me out?

Vich
10-20-2006, 05:26 PM
I've been trying to figure this out on my camera...I have an Olympus Evolt E-500...and I still can't figure out how to change the aperature even after reading the manual...can anyone help me out?

Don't know that camera, but they're all the same.

You'll have a "mode dial". Usually "Auto" setting is painted green. Among others, you'll always have a Tv, Av, and M. (Time, Aperture, Manual)

Av means "Aperture Priority". Meaning, you choose the aperture, the camera figures out the Shutter Speed.

So; if you select "Av", you can select the aperture you want.

JMK33
10-20-2006, 05:53 PM
Arite that makes sense...so then the camera will adjust the shutter speed accordingly?

The Mangler
10-20-2006, 06:21 PM
Arite that makes sense...so then the camera will adjust the shutter speed accordingly?
Yes. If you're using aperture priority (Av) you tell the camera what aperture to use and it figures everything else out. If you're using shutter priority (Tv), you tell the camera what shutter speed to use and it figures out the rest.

JMK33
10-20-2006, 06:23 PM
Arite..thanks a lot.I've been shooting in shutter priority recently...and I noticed why I couldn't change the aperature manually.
Thanks a lot!

gary_hendricks
10-21-2006, 08:59 AM
An aperture is the hole that allows light into your camera and determines the angles of rays. As such the aperture will affect your depth of field; stop or limit the effect of blurring of your image; and also determines the brightness of the image. As you already know, this can be adjusted. This is done in order to control the amount of light that actually reaches your film or your image sensor. When combined with shutter speed, an aperture will regulate the degree of which your film is exposed to light. As such, a faster shutter speed will require a larger aperture. Hopefully all of this makes more sense to you now and thus youíll be able to know what to look for the next time you purchase a camera. I know it took me a while to figure this one out too but now that I have itís been really helpful.