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Originally posted by swampfrog
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Sensors:
DSLRs have "full-frame" bodies and crop sensor bodies (Nikon or Canon). Full frame is really just a larger sensor chip. Manufacturing larger sensors is more costly than manufacturing a "crop" or smaller sensor of equivalent quality. The natural advantage of a larger sensor is it is more sensitive to light (more surface area), so ISO performance is improved (better low light performance). Sensor technology also continues to improve, so newer bodies with equivalent sized sensors get better results. The drawback to the larger sensor is cost, and not just in the body. The sensor is larger, which means the lens which focuses light onto the sensor must also be larger or placed further from the sensor, in order to illuminate the entire surface area when the shutter is released. Larger lenses are more expensive. The physics of sensor and lens alignment for a larger lens also results in a narrower depth of field, which throws the background more out of focus, which for most of us is a good thing as it isolates the subject from the background. In addition a larger sensor will capture an improved image geometry, straighter lines, less distortion.
Processors and Memory:
DSLRs are really mini computers, they have a CPU which takes the data from the sensor, performs some calculations based on a combination of firmware, hardware, software, and camera settings (parameters), and then passes the results to the memory storage system. Higher frame rates are a result of having a fast processor and a high throughput memory system. Typical memory cards are not fast enough to store higher burst rates, so the cameras with high burst capability have an internal memory buffer (kind of like a computer cache), that temporarily stores multiple images until the card can process the writes. The size of this higher speed memory buffer controls the number of images that can be shot in a burst. A camera might be capable of physically shooting 12 fps, but the memory system may only be able to deal with 6-7 RAW images before the buffer fills, then your at the mercy of your card speed as the buffer empties to the card. If you shoot jpeg only, then the buffer will be sufficient for significantly more images and sustain the 12 fps for multiple seconds. So while my daughter's T4i has a newer sensor, with better ISO performance that allows a faster shutter, the memory system is lacking so the 50D runs circles around it when it comes to fps. So just upping the ISO on the T4i does not allow it to compete with the 50D.
Stopping Motion:
If all you ever shoot is portraits and landscapes, fps will probably not interest you. If you're shooting your family and want to capture candid shots, stopping motion on a swing, stopping splashes at the water park or pool, etc. Then fps is fantastic. Shoot a burst and pick your favorite, rather than trying to time the shutter release at exactly the right moment.
DSLRs have "full-frame" bodies and crop sensor bodies (Nikon or Canon). Full frame is really just a larger sensor chip. Manufacturing larger sensors is more costly than manufacturing a "crop" or smaller sensor of equivalent quality. The natural advantage of a larger sensor is it is more sensitive to light (more surface area), so ISO performance is improved (better low light performance). Sensor technology also continues to improve, so newer bodies with equivalent sized sensors get better results. The drawback to the larger sensor is cost, and not just in the body. The sensor is larger, which means the lens which focuses light onto the sensor must also be larger or placed further from the sensor, in order to illuminate the entire surface area when the shutter is released. Larger lenses are more expensive. The physics of sensor and lens alignment for a larger lens also results in a narrower depth of field, which throws the background more out of focus, which for most of us is a good thing as it isolates the subject from the background. In addition a larger sensor will capture an improved image geometry, straighter lines, less distortion.
Processors and Memory:
DSLRs are really mini computers, they have a CPU which takes the data from the sensor, performs some calculations based on a combination of firmware, hardware, software, and camera settings (parameters), and then passes the results to the memory storage system. Higher frame rates are a result of having a fast processor and a high throughput memory system. Typical memory cards are not fast enough to store higher burst rates, so the cameras with high burst capability have an internal memory buffer (kind of like a computer cache), that temporarily stores multiple images until the card can process the writes. The size of this higher speed memory buffer controls the number of images that can be shot in a burst. A camera might be capable of physically shooting 12 fps, but the memory system may only be able to deal with 6-7 RAW images before the buffer fills, then your at the mercy of your card speed as the buffer empties to the card. If you shoot jpeg only, then the buffer will be sufficient for significantly more images and sustain the 12 fps for multiple seconds. So while my daughter's T4i has a newer sensor, with better ISO performance that allows a faster shutter, the memory system is lacking so the 50D runs circles around it when it comes to fps. So just upping the ISO on the T4i does not allow it to compete with the 50D.
Stopping Motion:
If all you ever shoot is portraits and landscapes, fps will probably not interest you. If you're shooting your family and want to capture candid shots, stopping motion on a swing, stopping splashes at the water park or pool, etc. Then fps is fantastic. Shoot a burst and pick your favorite, rather than trying to time the shutter release at exactly the right moment.
Wish I had the tripod so I didn't have to bump the ISO up, but still not bad for handheld. Shot RAW and post processed in Lightroom.
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