# Help me with this please



## Sunshine1 (Apr 5, 2010)

How do you set the "F-stop" on a Canon Rebel XT? I see absolutely nothing that says F-stop. 

And what does AF mode mean? The options beside it say : One shot,  AI Focus and AI Servo. HUH??

And also what does the metering mode mean? 

And lastly, and I know I sound like an idiot, but could someone remind me which speed goes with what lighting/setting the best? ( ISO speed 100, 200, 400 and so forth)

This has been driving me crazy. And I know you guys are great at your camera work, so I figured you could tell me in simple terms. 

Thanks!!!


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## GAranger1403 (Apr 5, 2010)

Ok, ISO is your sensitivity to light, it is generally best to shoot the lowest iso possible. The higher the iso the more artifacts"grain" will show up in your shots. In low light however it is sometimes neccesary to boost iso to get the shot. You can then edit out the artifacts with a program such as photoshop. And your right there is no setting that says fstop, your looking for the aperture setting. I'm not sure if your camera uses a button/menu screen or a command dial. I have cameras that use both but I shoot Nikon. Metering is what part of the shot your AF will focus on, generally you want to use center weighted metering. I highly recommend getting a users guide from Books a million on your camera. They are alot more in depth and easier to understand than your manual that came with the camera. Would read through that as well. Hope this gets you started, sure others more well versed than I will chime in as well!


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## leo (Apr 5, 2010)

can't help you with a canon, but here is an on line manual that may help you...  Index starts on pg 168 I think..

http://www.cleaningdigitalcameras.com/pdf/EOSDRXT350DIM-EN.pdf

here is a link on canon F stops too

http://photography-on-the.net/forum/showthread.php?t=217246


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## Sunshine1 (Apr 5, 2010)

It's frustrating when you know what kind of shot you want but you don't know how to manipulate your camera into getting it. 

Thanks guys...........


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## cornpile (Apr 5, 2010)

If you are on M mode all you have to do is press the Av button and at the same time turn the dial.

If you are on Av more all you have to do is turn the dial

Tv mode and P mode by doing the the same thing at that you do on M you will be adjusting the shutter and aperture at the same!


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## Smokey (Apr 5, 2010)

FloridaHunter said:


> It's frustrating when you know what kind of shot you want but you don't know how to manipulate your camera into getting it.
> 
> Thanks guys...........



When you get it figured out how 'bout helping me figure it out


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## Hoss (Apr 5, 2010)

The manual is a big help with these things.  At least it tells you how to adjust them.  Once you know that, it's a lot of learning how things interact.  I'd reccommend a little time reading the manual and then sit the camera up on a tripod and take photos of a stationary object adjusting one thing at a time.  When you aren't sure about something, back to the manual.  

Hoss


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## rip18 (Apr 5, 2010)

Yikes - just jump in and ask a bunch of complicated stuff all at once!  

Seriously, you've asked some good questions & gotten some good advice above...  

One of the guys that I shoot with a good bit says that the three most important things you can do to be a better photographer are: 1.  Read the manual, 2.  Read the manual, and 3.  Read the manual.  A lot of times, a "manual" written by someone other than the manufacturer of your camera is a whole lot easier to read & understand.  (Or even one of the videos...).



FloridaHunter said:


> How do you set the "F-stop" on a Canon Rebel XT? I see absolutely nothing that says F-stop.



F-stop is just aperture.  So if you want to adjust aperture (the size of the opening light goes through within the lens), then you'll normally shoot in aperture priority or manual mode.

Aperture priority mode is labeled (Av) on your dial.  When you are in that mode, you can let in more light (lower F-number) or let in less light (higher F-number).  Lower f-numbers mean a faster shutter speed and less depth of field.  Higher f-numbers mean a slower shutter speed and more depth of field.

The other modes on that dial (the important ones any way) are: Auto, Program (P), Shutter Priority (Av), and Manual.

The Auto mode in todays cameras is amazingly good.  In good light & "normal" conditions, you'll get an acceptable shot probably 90+% of the time.

Program mode (or P) is just Auto mode on steroids - it let you have a little bit of control - for example, you can adjust exposure compensation if you know that your subject/scene isn't 18% neutral... (i.e., it's weighted towards the lights or darks).  When I have to grab my camera & make a shot, Program mode or Aperture priority mode is what I want my camera to be in...  Some folks also call it "P for Perfect".

Shutter priority (Av) mode allows you to control the shutter speed in your camera (the camera chooses the aperture).  It can be good for capturing action when you select a fast shutter speed.

Manual (M) mode is when your camera lets YOU choose the aperture and shutter speed you want.

Depending on what you are trying to do, one of those options will likely let you have the control that you want.



FloridaHunter said:


> And what does AF mode mean? The options beside it say : One shot,  AI Focus and AI Servo. HUH??



AF mode is "AutoFocus mode".  This controls how your camera tries to focus on stuff when you depress the shutter release half way.

One shot is for just that - when you are going to take one shot of something still.  Basically, the camera focuses on it, and stops wasting internal memory & battery power on keeping up with it.

AI Servo is for something that is moving.  The camera's focusing sensors try to keep a moving object in focus (planes, kids, birds, race cars, etc.).  Choose it when you know your subject is going to be moving.

AI Focus is kind of a hybrid between the two.  It functions as "one shot" until the subject moves & then goes to AI Servo mode.  It would be good for many kid & wildlife photo attempts, because you never know when that static subject is going to take off at a right angle!



FloridaHunter said:


> And also what does the metering mode mean?



Metering mode is how your camera senses the image it is looking at.  You basically have 3 options: evaluative, partial, & center-weighted.  The camera is programmed to "see" whatever area you are metering as an 18% neutral gray (when very little in the real world is...).  This (to me) is one of the most important things to understand when trying to control your camera.  Once you understand what your camera is trying to do with the metering sensor, it is a WHOLE lot easier to try to outsmart it...

I'll start out with Partial metering (sometimes called spot metering in other cameras).  The Rebel takes the center 9% of the frame (often in a circle) and says, okay that is the area that I am metering on, and chooses the exposure (combination of aperture & shutter speed) to make that area a neutral gray color.

With the evaluative metering, the sensor looks at the average tonal values of the whole image and chooses an exposure to make that 18% neutral gray.

Center-weighted metering is kind of a combination of the other two - it takes the spot meter value for 9% of the area and weights it for 80% and the remaining 91% of the image and gives it a weight of 20% before determining an appropriate exposure.

Some folks swear by spot metering, some folks swear by evaluative metering, and other go blithely back & forth depending on the situation.  Basically, once you understand how to "read" tonal values & know what your camera is trying to do, then you can select an appropriate metering mode & use exposure compensation as necessary.  Or you can see what the camera wants to do in Aperture Priority & Shutter Priority, and then go to Manual Mode and adjust it to get the shot that YOU want...



FloridaHunter said:


> And lastly, and I know I sound like an idiot, but could someone remind me which speed goes with what lighting/setting the best? ( ISO speed 100, 200, 400 and so forth)



It depends on what you want to do...  In general, the higher ISOs work better in lower light, and the lower ISOs are generally better for brighter light.  I sometimes select an ISO to help me get an even slower or faster shutter speed, when I want either a really fast or a really slow shutter speed.

If you can shoot with somebody else who understands how their camera functions & is willing to work with you, that can be the best way to understand it.  A lot of times there are free or cheap one-day classes available.  A weekend or week-long workshop is also a possibility.  Best of luck!


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## Browtine (Apr 5, 2010)

rip18 said:


> In general, the higher ISOs work better in brighter light, and the lower ISOs are generally better for lower light.



Hey Rip, you are worlds better at, and more knowledgeable about this stuff than I am... but are you sure you worded the above quote right? If not, I'm bumfuzzled. I use higher ISO settings for lower light to get faster shutter speeds and use lower ISO in brighter conditions when achieving suitable shutter speeds isn't an issue.  If you meant it the way you posted it, please explain.


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## rip18 (Apr 5, 2010)

You are right, Browtine.  

Oooops!  I reckon my fingers got ahead of my brain...and my brain never caught up...  I'm glad somebody was proofreading all that stuff I wrote!  Many thanks!

I went back & corrected it to say: The Higher ISOs are used more in lower light and the lower ISOs are more useful in brighter light.











.


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## Browtine (Apr 5, 2010)

rip18 said:


> You are right, Browtine.
> 
> Oooops!  I reckon my fingers got ahead of my brain...and my brain never caught up...  I'm glad somebody was proofreading all that stuff I wrote!  Many thanks!
> 
> I went back & corrected it to say: The Higher ISOs are used more in lower light and the lower ISOs are more useful in brighter light.



Heck yeah, I try to read all of your posts. I've learned more than a thing or two by doing so.  I knew either you got it swapped up or I was about to learn something new!


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## Hoss (Apr 5, 2010)

Ok, this one gets put in the sticky.  Too much good information.

Hoss


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## Browtine (Apr 5, 2010)

Hoss said:


> Ok, this one gets put in the sticky.  Too much good information.
> 
> Hoss




Good call Hoss...


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## DRB1313 (Apr 5, 2010)

Here is my attempt at helping you understand how it all works.
It's an elementary kinda way of thinking, but I believe it will help you.

Pretend you are talking to the camera:

When you set the camera to auto, you are basically saying, "Hey Camera, I am going to push the button halfway down and I want you to do everything for me" and it will focus, set the ISO, activate the flash(if the camera has one)aperture and the shutter speed for the exposure.
Press the shutter button the rest of the way down and you have a photo.


Set the camera to "P" (Program) and you are basically telling the camera, Hey Camera, "I am going to push the shutter button halfway down and I want you to do everything for me, except now you have the option to set your ISO, turn off the flash or use exposure compensation.
All of these will let you modify the exposure if you choose to.

Raise the iso# and get a brighter photo in lower light or a faster shutter speed to stop motion if needed, but as 
warned, the higher the number, the higher the noise.

Press the shutter button halfway down and within 4 to 6 seconds, you can turn the main dial on the back, left or right to brighten or darken your exposure. (Learn this!!)

Set the camera to AV and you are still saying the same thing to the camera as with program, but now you are adding the comment,Hey Camera, "I am going to set my aperture first, then I will push the shutter button halfway down and you do everything else" and it will do so.

Aperture(F-Stop controls the depth of field) the lower the number the less depth of field you will have, but it will give you the faster shutter speeds.  The higher the number, the more depth of field you will get, but you will also get slower shutter speeds.

Remember Exposure compensation!!!

If you set the camera to TV, you are once again telling the camera the same
thing, but this time you are in control of the shutter speed and the camera sets everything else.

Remember Exposure compensation!!

Set the camera to M and you will be telling the camera, Hey camera, I am in charge here, just do what I tell you!!

So, try this exercise,  Set your camera to AV, make sure you are at iso 100 and outside in bright light.

Take a pill bottle or something small and set it up on the driveway.
Now get as close to the object as your camera and lens will focus automatically, this is what is called the minimum focusing distance of the lens you are using.
set the aperture to the lowest number that it will go to and make sure if you are using a zoom lens to zoom all the way in.
A tripod will help with this if you have one.
Take a photo from that distance, then change the aperture up one, by using the dial on top, take another shot.
Keep doing this all the way up to around f11, you will see how shutter speed works with aperture(F-stop) and you will also see the depth of field change as you review the pics on the computer.
This should get you started in understanding things.

Check the stickys at the top and look for one called understanding iso.
There are also a lot of other good tutorials there also.

Keep on clicking!!


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## rip18 (Apr 6, 2010)

Well said, DRB1313!


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