Sharpness Tests of the Sigma 14mm f/1.8 DG HSM Art

Kyle Jones

Kyle Jones

Moderator
Interesting read. I'm one that would like to see this tested against the new Rokinon 14 f/2.4. I ended up getting the Rokinon instead of waiting for the Sigma. I've loved it so far - being 1/2 the price and 2/3 the weight doesn't hurt.

I'd also be interested in seeing how much vignetting the Sigma has wide open. What I've seen with the Rokinon is that it seems brighter at 2.8 than at 2.4! I've heard similar things about the Sigma.
 
JimFox

JimFox

Moderator
Staff member
The Rokinon 14 f2.4 was on my list to buy, the problem is they haven't released it in a Nikon mount yet. I have the Rokinon 14mm f2.8, but I have now had 2 of them get the lens decentered just from normal use. That was discouraging. But I was willing to give the f2.4 version a try, but as I said it isn't available on Nikon.

So that's a big reason I went for the Sigma 14mm f1.8. Plus, I decided there would be very little difference between f2.8 and f2.4 in terms of light allowed in, but to go from f2.8 to f1.8 is much more substantial.

I have shot 2 nights with the Sigma 14mm f1.8, and my initial response is very positive with it.

If only we shot with the same body, we could go shoot somewhere and swap lenses to compare. :)

Jim
 
JimFox

JimFox

Moderator
Staff member
xpatUSA said:
https://www.lenstip.com/506.8-Lens_review-Sigma_A_14_mm_f_1.8_DG_HSM_Vignetting.html
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Thanks! Yeah, it's hardly a bother.

His testing here might miss the point a bit as he says it cleans up by f2.8. But the whole point of getting a really fast lens like this to photograph the night sky is you don't want to then throttle it. I shoot mine at f1.8 probably over 95% of the time. The only time I will close it down a stop or two is if the moon gets in the image. Though I try to avoid the moon since the moon will wash out the stars.
 
xpatUSA

xpatUSA

Well-Known Member
JimFox said:
Thanks! Yeah, it's hardly a bother.

His testing here might miss the point a bit as he says it cleans up by f2.8. But the whole point of getting a really fast lens like this to photograph the night sky is you don't want to then throttle it. <>
Click to expand...
In that same link they also test the MTF50 over a range of f-numbers:



Looks like there's transparency involved - open the image in a new tab to see it mo' better!

It does show an increase in sharpness (MTF50) going up from f/1.4 to a peak at f/4, so maybe that's what was meant by "cleans up" ...
 
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