mmilkov

According to this site, the Sigma is not as sharp, especially at 200 mm and f2.8, and also has more chromatic aberration: http://slrgear.com/reviews/showproduct.php/product/1328/cat/31

Here is one DOF calculator that I found: http://www.dofmaster.com/dofjs.html

I hope you can help me settle an argument with my friend.A few days ago he and I started talking about depth of field (DOF) of SLRs vs. point-and-shoot cameras. He thinks that SLRs have shallower...

Okay, I think I found my mistake. Bob, you are right. The following would be equivalent in terms of FOV, DOF and Airy disc size for the same print size:FX 50 mm lens f/12DX 33 mm lens f/8

Bob,Thank you for the example.If I understood you correctly, you first show that, for the same f-number, the size of the Airy disc in a printed picture of the same size will be larger for DX than...

I think I get it. Let's say you start with a 50 mm f1.8 lens on FX. In order to obtain the same FOV on DX, you need to increase the focal length to 75 mm. Since the focal length is now longer, the...

1. In terms of depth of field, an f2.8 lens on DX is equivalent to f4.2 on FX.2. In terms of diffraction, an f2.8 lens has the same diffraction limit whether the sensor is DX or FX. This is because...