2 replies to this topic

[Kaypi]

Hi!

 

I`m thinking of upgrading from Nikon D5100 to Nikon D7100 along with that getting a Sigma 18-35mm f1.8.

 

My question is since the Nikon D7100 has a 1.5x crop factor at 24MP, the Sigma 18-35mm f1.8 will behave as 27-52.5mm f1.8 lens

Also since the Nikon D7100 has an additional 1.3x crop at 16MP (1.5*1.3 = 1.95) does it mean the Sigma 18-35mm f1.8 also can act as a 35.1-68.25mm f1.8? If so, how good is it? I am happy with the 16MP in Nikon D5100. This way D7100 plus the Sigma 18-35mm combination makes a stunning 27-68.25mm f1.8 lens which is amazing!!

 

I have a Tamron 17-50mm f2.8 which I am using along with the Nikon D5100. I am pretty happy with that but thinking to upgrade to Nikon D7100 with the extra cash I have. 

 

Please tell me if I`m getting it wrong somewhere

 

Thank You.

[Adam]

The Sigma 18-35mm is specifically designed for DX sensors like that in the D7100.  The field of view is equivalent to that of a 27-52.5mm mounted on a FX body, but that doesn't mean that the focal length actually changes.

 

As for the lens itself, it's very sharp- almost like having a bag of primes.  I highly recommend it if you do a long of wide-angle and normal shooting, especially in low light.

[Afterimage]

Kaypi - you got it right, the additional 1.3x Crop does , basically, make the 18-35 into a "36-70mm lens". Keep in mind that it's just "turning off" the extra pixels making the 24MP convert to down to 16. I've heard that it's better than cropping in post by some and worse from others. I tend to believe that since you are using the sharpest part of the lens to fill the frame the IQ would be the same if not better in certain circumstances. It certainly feels that way when I use the 1.3X on a macro lens...

 

Personally I use the additional 1.3x frequently. The big bonus you get in using it is that the entire frame if filled with the 51 AF-points... edge to edge which is especially useful for actions shots.