This morning I had the opportunity to test out the new Sigma 14-24mm!  For this test, I drove down to the local "dark" sky park in Ohio and took some test shots.  As you will see, it's virtually impossible to find a truly dark sky here in Northeast Ohio...  Just 2 more weeks and I'll be back under an actual dark sky - in the Utah desert!

*If you would like to get a closer look at these photos, you can download the full-resolution JPEGs here.  Desktop users can click the download icon at the top-left of each image.  Mobile users can scroll up, click the arrow in the upper right, and click download.

 

RAW Photos

This first comparison looks at the RAW files, straight out of camera, at both 14mm and 24mm.  The 14mm photos were taken at f/2.8, ISO 800, and 15 seconds, while the 24mm images were shot using an 8 second Shutter Speed.

*Note: The Nikon image is slightly out-of-focus in the 24mm example, making the stars appear brighter / larger

Nikon @14mm

Sigma @14mm

Nikon @24mm

Sigma @24mm

Edited Photos

For this comparison, I increased the Exposure, Saturation, Contrast and I reduced the Highlights.  I also used the automatic Lens Profile Correction for the Nikon to remove the vignette, and fixed the vignette manually on the Sigma.  The same edits were applied to each photo.

Nikon @14mm

Sigma @14mm

Nikon @24mm

Sigma @24mm

Coma / Astigmatism

I cropped heavily into the upper right corner of the image, to show a clear look at any star distortion.  The Shutter Speed was 15 seconds, which means there is a slight amount of motion blur due to the Earth's rotation.

Nikon

Sigma

Vignette

For this comparison, I took the edited images, removed any Profile Corrections, and brightened the Sigma by roughly 1/3 Stop to compensate for the T/Stop difference.  At this point, we should have a clear look at the vignette for each lens. 

Both lenses have minimal vignette, however the Sigma has a slight advantage.  The Nikon is rated at -1.6 EV on DXO Mark, I would guess the Sigma will be rated around -1.5 EV.

Nikon

Sigma

Verdict

Overall, the Sigma did a fantastic job!  Remember, you can visit the image gallery and download all the test images for a better look.  Also, if you want an even more in-depth look at how the Sigma 14-24mm performs, here's Dustin Abbot's fantastic video review. 

Let's break down each point:

• Coma: I was very impressed with the Sigma's coma performance!  Both lenses do remarkably well, but the Sigma does a slightly better job. 

• Transmission: After carefully comparing the images, the Sigma appears to be a 1/3 Stop darker than the Nikon.  The Nikon is rated at T/3.0 Stops, which would make the Sigma roughly T/3.3 Stops.

• Distortion: The Nikon is just slighly wider at 14mm than the Sigma, however the Sigma appears to have better distortion control.

• Colors: The color balance on the Sigma is quite close to the Nikon 14-24mm, but slightly warmer.  By subtracting 200K and adding +4 Purple Tint, I was able to get the Sigma looking nearly identical to the Nikon 14-24mm.

• Vignette: There is minimal vignette on both lenses, but the Sigma has a slight advantage.  The Nikon is rated at -1.6 EV on DXO Mark.

• Cost: The Nikon 14-24mm is still going for $1,900, even after all these years, while the brand new Sigma 14-24mm costs $1,300!

• Focusing: Having spent a lot of time focusing lenses at night, I found the Sigma to be a bit easier to achieve sharp focus.  

After these tests, it's clear that the Sigma 14-24mm Art lens will make an excellent addition to any night photographer's collection!

To learn more about Astrophotography, be sure to check out my free tutorial!