D7100 crop - what is it?

Started Jan 2, 2014 | Discussions thread
BirgerH Veteran Member • Posts: 5,904
Re: Actually, it's a 1.25x crop...

Stephen Knox wrote:

draacor wrote:

blurredvision wrote:

JimPearce wrote:

The "1.3x" refers to a linear crop factor. A better way to look at it in my view is the reciprocal: only 1/1.25 or 80% of the pixels (linearly) are retained. The raw file is 4800 x 3200 pixels rather than 6000 x 4000.

To further dumb down what Jim has written, I'll add this much. By default, the D7100 is 24MP. Kick on 1.3x crop mode and your pictures go down to around 15.3MP. This helps get more pictures in the buffer due to the smaller file size, only helpful if you do continuous shooting. Other than that, there's no advantage to it.

IMO, I think Nikon knew the buffer was lacking and threw in this Band-Aid as a "feature".

I disagree with this. Another useful thing is for wildlife photography. Instead of buying a longer zoom lens you can turn on the crop to get a little closer in. Sure you can do this in post but it makes framing easier when you do it out in the field.

Isn't that (the bold text, in particular, the underlined bit) a myth? I often hear that the 1.3x crop mode gives you more reach, i.e. it gets you in a little closer, but it simply doesn't.

Compare an image shot in the normal mode with an image shot in 1.3x crop mode and the one shot in 1.3x crop mode is merely a rectangle cut out of the image that would have been shot in normal mode, i.e. that cropped area already exists in the image shot in normal mode and at the same size and resolution, i.e. there has been no "getting in a little closer", just a cutting away of pixels surplus to requirement.

The image shot in 1.3x crop mode is not magnified or anything, it hasn't got you any closer to the subject, it's exactly the same size and resolution as the relevant area on the image shot in normal mode that it came from.

Or am I talking out of my butt cheeks? Or maybe I've just misunderstood the way you put it and we're actually in agreement. I hope it's the latter, LOL.

No - you are right.

Taking two shots with exactly the same focallength and exactly the same distance to the subject in focus and with the exact same aperture on different sized image-planes - is just giving you a cropped Picture - which could be done in PP just as easily.

Magnification is determined alone by the focallength/(focallenght-distance to the subject) - and none of those parameters are changed.

The dof will be just the same, because you have the less part of the Picture on the less part of the image-plane.


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