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I understand the differences between the two types, but I am getting a bit confused when it comes to lenses. Eg. a 50mm lens on a crop sensor camera would be 80mm (x1.6). I get that... but in my research, I have read that it magnifies the image and in other places, I have read that it's the field of view that is similar to the 80mm. Just need some clarification. Thanks,


-- Nash

It's a FoV crop... so the full-frame 50mm lens takes on the field of view of an 80mm lens when fitted to a crop-frame camera. The focal length is still 50mm, it's just the field of view is cropped. The "crop-factor" is just a way of giving you an idea of what kind of field of view you're going to get taking into account the size of the sensor.

Think about point-and-shoots or bridge cameras... they have *tiny* sensors, and their lenses are often rated in single-digit numbers, but via THOSE crop factors (3x or more in some cases) they have "35mm-equivalent" fields of view.

Lens characteristics, i.e. compression, distortion, etc are the same, although because you're losing bits off the full image circle they may not be as apparent. That's partly why I don't like to use my 35mm lens on my 7D because the edges of the frame (which get cropped off) are what makes that lens so interesting on full-frame!

A visual aid and explanation (just found via random googling): http://www.garydatesphotos.com/2010/ful ... ed-sensor/

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Just a small clarification: at least for Canon, almost all point-and-shoots and bridge cameras (the GX1 is an exception, for example) have a crop factor of 5.6x, and I've personally confirmed this.

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Great article... and as I was reading... everything seemed to make sense, until the last paragraph.....



He talks about the FOV (80mm) but then says image magnification!! I am assuming that he's talking about the image sensor size which cuts off the image real estate that a full frame camera would give...

-- Nash

Other exceptions: the "S" line--e.g. S95, S100, S110, etc.--and "G" line--e.g. G11, G12, G15, etc.



Yes, the term "magnification factor" is sometimes used because the crop factor can appear to magnify the image. e.g. print out the red outlined area in the example image above so it fills, say, a 6x4" piece of paper, and print out the yellow outlined area so it also fills a piece of paper the same size (in this example, 6x4"). The print out of the yellow area will appear to be a magnification/enlargement/blow-up of the middle of the print out of the red area. (In this case, it actually would be an enlargement, but remember that the premise is that a given lens will capture the red area when mounted on a full frame camera, and that same lens will capture the yellow area when mounted on a crop frame camera. In other words, this is supposed to represent two different images captured with two different cameras, so in that "real world" case, one would not be an enlargement of the other.)

HTH - Mark