f stop feature explained???

i am new to digital photography.

i am having a tough time trying to fully understand the apeture (f stop) function.

if i set my camera to 2.8 f stop, i have been told that the focus tends to zone in on the sunject and the backdrop looks more blury / distant.

where as if you have a f stop - appeture of f22 for example the focus is on the whole picture (depth of field is 100% like a landscape shot)

is this right?

but what confuses me is, it does not seem to matter what f stop i use, the focus range (dept of field doesnt seem to be anmy different)?

the only difference i notice with f stop feature is the higher the number (i.e f22)

the darker the shot / less light is let in.

and the smaller the number (i.e. f 2. the more light the lens lets in.

can anyone coach me better on this major feature on our cameras?

.

also, it sometimes seems so hard to really know whats a better choice

when looking a light reading / metering

as in - how do u know whats a better option

i.e. do u increase shutter spead to lets less light in or do u reduce your fstop value (2.8 for exapmle) to let more light in etc......

What camera/lens are you using? You wont notice it as much if you are using a long lens, 200mm +. When you stop down (moving to a higer f number) the more of the background will be in focus, but at such high focal lengths, there is still blurry background.

You have it pretty much right though, the smaller f number, the more light is let in, which results in shallower depth of field. The larger the f number, the less light in, which results in more depth of field.

For your last question, it depends on what you want your picture to look like. If you want it to be perfectly exposed, and you are in "M" mode, when looking through thte viewfinder, there are lines at the bottom (depending on what camera you have) and to properly expose the shot the bar has to reach the middle.

Try shooting RAW, the cameras uncompressed file format, you will need a RAW editing program, such as "Raw shooters essentials", "Adobe camera RAW", "Adobe lightroom" and many more. That way when you take a shot, you can after choose which exposure you like best.

Hope my rambling made some sence, good luck.

hey mate,

thanks for that info.

it makes sense...

i think what i have noticed using DSLR compared to compact cameras is

that even thought u might use a f22 stop (which lets less light in)

when that f stop is used - they say it creates a better "dept of field"

but when i hit the shutter half way down, regardless of the "AF" points used

(i.e 1/2/3 point)

it still seems to focus on one area more than the other,

where as with compact cameras, the lens gives an all round 100% sharpness to the entire shot. with slr, it never seems to be fully sharp on th entire picture

know what i mean.? its more focused on the area you have set to AUTO FOCUS af point.
even when u shoot on a f2.8 stop,

it lets more light in but still focus's on an area of the picture, i cant see much difference

with focus range between the 2 stops

i just see the light/dark range varies

.

i am using a 4.0 - 5.6 focal length lense

canon d60

why dont you take an introduction to photography class? if your that unsure about fstops, i suggest you do this. otherwise, your never going to be sure about your end result.

cheers,

i am already doing a dig photo course,

only been doing it for 2 weeks out of 7.

the teacher is very general by saying

f2.8 lets in plenty of light and tends to blur the backdrop.

and then says, the f22 gives a sharp photo 100% (the entire shot)
and lets less light in,

this is very general.....

forums like this can help further i say, along with practice

This is an excellent resource for learning...

http://www.canon.co.jp …ng/enjoydslr/p_​2_007.html

Understanding Exposure is a good book to ckeck out too.

Jon.

thanks guys

if there are any general tips please do write them down.

for me, i guess this is what photography is all about - but for mew

knowing when to use the f stop over what shutter speed to use is the challenge

in some cases, its just not easy to know to go for a higher stop over a lowee shutter speed,,

I'll admit, this was one area of photography that really confused me when I first started. The thing that got me was that the bigger the number, the smaller the aperature opening. Who came up with that idea? (I know, it's some math thing that I will never understand.) The way I finally got it was to shoot... A LOT! You'll get it! Have fun in your class and post lots of pictures.

Check this site out.
The items in the left hand sidebar link to other useful information re: depth of field, lens aperature, etc.

Getting this concept down will allow you to better understand the other critical factors in getting a good exposure (shutter speed and ISO) for which there are other online resources to tap.

As someone noted upthread, Bryan Peterson wrote a book "Understanding Exposure" ($14 USD @ Amazon) that contains good information on how you put all the elements together (focal length, aperature, shutter speed, and ISO).

Good Luck and welcome to POTN!

Cheers

thanks

o

There is no substitute for reading a good book and then doing the work. The book suggested by Bryan Peterson is one I bought right off after joining this forum. I don't know if you can get a copy from your local store, but Amazon has it and I absolutely read the whole thing and did almost every suggestion (like a tutorial). I learned so much and even shoot Manual more than I ever thought I'd dare. The people here can try to explain it to you, but until you go out and work on the settings, you won't get it. Shoot a few things, tell us your settings and we can help. Otherwise, buy the book, have fun with your camera and lenses. Just remember one thing about aperture, if your lens is f4.0-5.6, you can't go under 4.0. If you have a lens that shoots f2, but you can adjust the camera and the lens can respond, you have much more flexibility.

thanks suzie/

can u tell me / remind me of the full name of the book u suggest?

I think this is the book Suzy was referring to. It's by Bryan Peterson.