Last week during the short talk about focal length, I mentioned there was a difference between what is called a full frame sensor and a smaller sensor size that results in what is called a "cropped factor".
A 35mm camera is called a 35mm camera because of the size of the film. The film that goes into the camera is 35mm across. When a picture is taken the film negative is a2:3 proportion (part of the reason photos are usually printed as 4x6in size).
So on what is called a full frame digital camera (e.g., NIkon D3, Canon Mark III) the camera has a sensor size that is the same size as a 35mm piece of film (i.e.,35mm). This means on a full frame digital camera, the image projected on the sensor is the same as the image that would be projected on a 35mm piece of film.
What happens when the sensor size gets smaller? Is the whole image coming through the lens going to be projected on the sensor? No. Only a portion of the image will be projected on the sensor or the image will be "cropped".
The "crop factor" or how much the projected image will be cropped will depend on the brand of camera the photographer is using. A Nikon camera for instance, has a crop factor of 1.5x. This means the image on the sensor is cropped by 1.5x. What does this mean for the relationship with the focal length?
The Math (based on Nikon crop factor of 1.5)
Real Focal Length = Stated Focal Length x 1.5
so a 50mm lens is really
50mm x 1.5 = 75mm
Why are camera companies making smaller sensors for cameras? Because it costs less. A full frame digital camera may cost $7,000. A consumer grade DSLR costs $500. To be sure a full frame DSLR has a ton of bells and wistles in addition to a full sized sensor, but still this is a key factor distinguishing a cream of the crop professional level camera.
Is a full frame camera better than a camera with a smaller sensor? All I will say is I feel the best camera is the one you are using.
Here is a good resource: Crop Sensor Vs. Full Frame from The Photo Junkies
A 35mm camera is called a 35mm camera because of the size of the film. The film that goes into the camera is 35mm across. When a picture is taken the film negative is a2:3 proportion (part of the reason photos are usually printed as 4x6in size).
So on what is called a full frame digital camera (e.g., NIkon D3, Canon Mark III) the camera has a sensor size that is the same size as a 35mm piece of film (i.e.,35mm). This means on a full frame digital camera, the image projected on the sensor is the same as the image that would be projected on a 35mm piece of film.
What happens when the sensor size gets smaller? Is the whole image coming through the lens going to be projected on the sensor? No. Only a portion of the image will be projected on the sensor or the image will be "cropped".
The "crop factor" or how much the projected image will be cropped will depend on the brand of camera the photographer is using. A Nikon camera for instance, has a crop factor of 1.5x. This means the image on the sensor is cropped by 1.5x. What does this mean for the relationship with the focal length?
The Math (based on Nikon crop factor of 1.5)
Real Focal Length = Stated Focal Length x 1.5
so a 50mm lens is really
50mm x 1.5 = 75mm
Why are camera companies making smaller sensors for cameras? Because it costs less. A full frame digital camera may cost $7,000. A consumer grade DSLR costs $500. To be sure a full frame DSLR has a ton of bells and wistles in addition to a full sized sensor, but still this is a key factor distinguishing a cream of the crop professional level camera.
Is a full frame camera better than a camera with a smaller sensor? All I will say is I feel the best camera is the one you are using.
Here is a good resource: Crop Sensor Vs. Full Frame from The Photo Junkies
This photo was taken with a focal length of 210mm on a camera with a sensor that has a 1.5 crop factor. What would have happend if the photo was taken with a focal length of 210mm on a camera with a full frame camera? What else might be in the frame?
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