With a 300mm lens on an 8x10 view camera a photo capture of a house may show the entire house with six windows, each one of which is 36mm on the negative. I thought the OP's question was referring to a projected image of the sensor capture. This is complicated further by issues of pixel density, but let's not stray to far from the OP. It's why crop sensor cameras have greater "reach" at a given focal length. This was not the OP's question, and is exactly the same effect regardless of whether one uses an EF-S or an EF lens, but it is a source of considerable confusion when people talk about sensors of different sizes. However, changing sensor size does change the relative size of the projected image with respect to the frame-the smaller the sensor size, the larger the proportion of the sensor filled by a projected image of a given size. It doesn't affect the dimensions of the projected image, which are entirely a function of focal length and distance. Sensor size, on the other hand, does matter. Using different lenses of the same focal length (if they really are the same focal length) will not change this, and EF-S 200m lens has the same focal length as an EF 200mm lens. The size of an image projected on the sensor is a function of focal length and distance to the subject. The distinction between EF EF-S lenses is completely irrelevant to this question. ![]() ![]() So if an 8x10 inch photo were made from each the lighthouse would be the same size on each 8x10 photo? The only effect of using an EF lens is that you are carrying a bigger, heavier lens than you need to, all other things being equal. The answer to the OP's question is that the choice between an EF or an EF-S lens has no effect whatever on the image captured by an APS-C camera. All that happens is that the APS-C sensor will not see some of the larger image circle created by the EF lens. But the image cast on this smaller sensor by an EF lens is exactly the same. I think in using the term "field of view" you may be confusing the size of the image circle captured by the lens with angle of view.īecause APS-C cameras have a smaller sensor, they don't need as large an image circle, and EF-S lenses, which are designed to cover only that smaller circle, can be smaller (in diameter). If you put an EF-S 200mm lens on an APS-C camera, you will get exactly the same image as if you put an EF 200mm lens on the camera. The main difference is the that the optical 'field of view' on an EF-S lens is designed for an APS-C camera and will give a wider 'field of view' (say, 100%) on an APS-C camera than an EF lens That's what people mean when they say that a crop sensor camera has more "reach" or that one gets a similar view with a shorter focal length. This is another way of saying that the angle of view is smaller. However, because the frame is smaller on an APS-C camera, if you are not cropping, the subject will fill a larger portion of the frame on the APS-C sensor. if you crop the FF image to the size of the APS-C image, the subject would fill the same portion of the APS-C image and the cropped FF image. ![]() ![]() The magnification-the size of the projected image relative to the size of the subject-is exactly the same it's determined solely by the distance and focal length. Suppose that you put a 200mm EF lens on two cameras, one APS-C and one full frame, and take a photo of the same subject at the same distance. What generates endless debate and confusion is something different. EF-S lenses differ from EF lenses in two respects, neither of which is relevant to this: a shorter flange distance (because APS-C mirrors are smaller), and narrower glass (because you don't need the larger image circle that extends beyond the sensor.) Whether the lens is EF or EF-S has nothing to do with it, assuming that they are the same focal length. The angle of view for a given focal length is determined by the sensor size.
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