best lens canon xti rebel image
Wiener
i have a canon rebel xti and i wan't to learn on how to understand how to use all the settings on the camera. i tried reading the manual but it confuses me. i am planning on buying a book that covers all of this stuff but i'd like to know what aperture and F stops and all that stuff mean from u guys....thx
how can you get a nice bokeh for portraits
Answer
You might check at http://www.magiclanterndvdguides.com for an instructional DVD for your camera.
These books might help:
"How Digital Photography Works, Second Edition" by Ron White
"Hands-On Digital Photography" by George Schaub
There are 3 components to the "Exposure Triangle" : f-stop, ISO and shutter speed.
ISO is the measurement of the sensitivity to light of a light sensitive surface, either film or digital sensor. A low ISO (50, 100) is very insensitive and requires a lot of light. A high ISO (400, 800, 1600) is very very sensitive and requires less light. A low ISO produces the best image quality; a high ISO is needed in low-light, non-flash photography but does degrade the image.
The aperture (f-stop) is the opening made by the diaphragm inside the lens on your camera. A large opening (f1.7, f2) admits all the available light. A small opening (f11, f16) admits very little light. Regardless of the ISO chosen, the f-stop chosen controls the shutter speed and what's known as "Depth of Field" (DOF).
The shutter speed determines the length of time the light admitted by the f-stop chosen is allowed to expose our film or digital sensor, based on the ISO.
Let's look at some examples to see the ISO/f-stop/shutter speed relationship. These are based on the "Sunny 16 Rule" which states: "On a sunny day, set your aperture to f16 and your shutter speed to 1/ISO". * For our purposes we'll pretend our fastest shutter speed is 1/8000 sec. - which few cameras have the capability of achieving.
ISO 100
f16 @ 1/125 sec.
f11 @ 1/250 sec.
f8 @ 1/500 sec.
f5.6 @ 1/1000 sec.
f4 @ 1/2000 sec.
f2.8 @ 1/4000 sec.
f2 @ 1/8000 sec.
ISO 400
f16 @ 1/500 sec.
f11 @ 1/1000 sec.
f8 @ 1/2000 sec.
f5.6 @ 1/4000 sec.
f4 @ 1/8000 sec.
As we ''open up" from f16 to f11 we admit twice as much light and our shutter speed doubles since admitting more light requires less time (faster shutter speed) for the light to expose our light sensitive surface.
If you doubt the validity of the example, do this simple test:
Place your camera in Aperture Preferred Mode so you can select an f-stop and allow the camera to select the shutter speed. (Av on your camera). Set your ISO to 100. Now go outside on a sunny day. Set your f-stop to 16 and record the shutter speed selected by the camera. Do this for every f-stop.
The only difference you'll likely see from the chart I showed is this: The "Sunny 16 Rule" my chart is based on was developed when shutters were 100% mechanical. Today's modern electronically controlled shutters are essentially "stepless" and will come closer to actually matching the 1/ISO part of the "Rule".
Depth of Field (DOF) is controlled by the f-stop and the focal length of the lens. It is loosely defined as that area in acceptable focus in front of and behind your subject. You can find an excellent explanation on wikipedia. I'll just say that a wide-angle lens (18mm, 21mm) will give you maximum DOF at f16 while a telephoto lens (100mm, 200mm) will give you a shallow DOF at f16.
OK, I can't resist just 2 examples:
21mm lens @ f16, focused at 6' : DOF is from 2' 2'' to Infinity
200mm lens @ f16, focused at 8' : DOF is from 7' 9-3/4'' to 8' 2-3/8"
Its easy to see how shallow our DOF is with a 200mm lens: 4-5/8" (2-1/4" in front of and 2-3/8" behind our subject).
I realize this has been a long and somewhat complicated answer.
Good luck with this fascinating, frustrating thing called photography.
You might check at http://www.magiclanterndvdguides.com for an instructional DVD for your camera.
These books might help:
"How Digital Photography Works, Second Edition" by Ron White
"Hands-On Digital Photography" by George Schaub
There are 3 components to the "Exposure Triangle" : f-stop, ISO and shutter speed.
ISO is the measurement of the sensitivity to light of a light sensitive surface, either film or digital sensor. A low ISO (50, 100) is very insensitive and requires a lot of light. A high ISO (400, 800, 1600) is very very sensitive and requires less light. A low ISO produces the best image quality; a high ISO is needed in low-light, non-flash photography but does degrade the image.
The aperture (f-stop) is the opening made by the diaphragm inside the lens on your camera. A large opening (f1.7, f2) admits all the available light. A small opening (f11, f16) admits very little light. Regardless of the ISO chosen, the f-stop chosen controls the shutter speed and what's known as "Depth of Field" (DOF).
The shutter speed determines the length of time the light admitted by the f-stop chosen is allowed to expose our film or digital sensor, based on the ISO.
Let's look at some examples to see the ISO/f-stop/shutter speed relationship. These are based on the "Sunny 16 Rule" which states: "On a sunny day, set your aperture to f16 and your shutter speed to 1/ISO". * For our purposes we'll pretend our fastest shutter speed is 1/8000 sec. - which few cameras have the capability of achieving.
ISO 100
f16 @ 1/125 sec.
f11 @ 1/250 sec.
f8 @ 1/500 sec.
f5.6 @ 1/1000 sec.
f4 @ 1/2000 sec.
f2.8 @ 1/4000 sec.
f2 @ 1/8000 sec.
ISO 400
f16 @ 1/500 sec.
f11 @ 1/1000 sec.
f8 @ 1/2000 sec.
f5.6 @ 1/4000 sec.
f4 @ 1/8000 sec.
As we ''open up" from f16 to f11 we admit twice as much light and our shutter speed doubles since admitting more light requires less time (faster shutter speed) for the light to expose our light sensitive surface.
If you doubt the validity of the example, do this simple test:
Place your camera in Aperture Preferred Mode so you can select an f-stop and allow the camera to select the shutter speed. (Av on your camera). Set your ISO to 100. Now go outside on a sunny day. Set your f-stop to 16 and record the shutter speed selected by the camera. Do this for every f-stop.
The only difference you'll likely see from the chart I showed is this: The "Sunny 16 Rule" my chart is based on was developed when shutters were 100% mechanical. Today's modern electronically controlled shutters are essentially "stepless" and will come closer to actually matching the 1/ISO part of the "Rule".
Depth of Field (DOF) is controlled by the f-stop and the focal length of the lens. It is loosely defined as that area in acceptable focus in front of and behind your subject. You can find an excellent explanation on wikipedia. I'll just say that a wide-angle lens (18mm, 21mm) will give you maximum DOF at f16 while a telephoto lens (100mm, 200mm) will give you a shallow DOF at f16.
OK, I can't resist just 2 examples:
21mm lens @ f16, focused at 6' : DOF is from 2' 2'' to Infinity
200mm lens @ f16, focused at 8' : DOF is from 7' 9-3/4'' to 8' 2-3/8"
Its easy to see how shallow our DOF is with a 200mm lens: 4-5/8" (2-1/4" in front of and 2-3/8" behind our subject).
I realize this has been a long and somewhat complicated answer.
Good luck with this fascinating, frustrating thing called photography.
Can you use lenses from a Canon 35mm film camera on a digital canon rebel xti? Are they compatible?
caligirl
I have a couple of lenses from my Canon 35mm camera and have now purchased a new digital Canon rebel xti. Can I use the lenses from my old 35mm on a digital rebel xti?
Answer
It depends on what "35mm film camera" you have. If you have an old Canon FD-mount camera (which means Canon's manual focus cameras made before the 90s) you'll need an adapter:
http://search.ebay.com/canon-fd-to-ef_W0QQfsopZ32
If you have an EOS 35mm camera with EF-mount lenses then they should mount and work exactly like they're suppose to.
In any case, since the sensor of the XTi is smaller than a frame of film, there's a 1.6x crop factor that you have to take into account. A 28-80mm lens would be equivalent to a 44.8-128mm lens on the XTi.
It depends on what "35mm film camera" you have. If you have an old Canon FD-mount camera (which means Canon's manual focus cameras made before the 90s) you'll need an adapter:
http://search.ebay.com/canon-fd-to-ef_W0QQfsopZ32
If you have an EOS 35mm camera with EF-mount lenses then they should mount and work exactly like they're suppose to.
In any case, since the sensor of the XTi is smaller than a frame of film, there's a 1.6x crop factor that you have to take into account. A 28-80mm lens would be equivalent to a 44.8-128mm lens on the XTi.
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