I, like many photographers, have been going back and forth trying to decide which of these are better. I had seen some things that just made me wonder. In my earlier test, it was shown that the bokeh from the Sigma was dramatically different. The Sigma also just had that “wow” factor that I couldn’t seem to get from the Nikkor, even though the Nikkor was seen to be sharper in some cases, the Sigma in other cases. I liked the weight from the Nikon, but the “pop” of the Sigma.
I was confused.
I even spent some time on the Leica forums asking what made a lens “pop”. What makes the rendering of a certain lens special?
So this weekend, I set out to find out once and for all, what’s the best fast 35mm autofocus prime in the world on a D800. The results may surprise you.
First off, I started out in my darkened apartment to test for both sharpness and bokeh. Allow me to introduce Green, my willing subject.
While you can click through to examine to your hearts’ content, I’ll save you some pixel peeping: in the center, they are effectively identical. But something is going on at the edges of the frame. The Nikkor spanks the Sigma!
Even at f/2.8, the Nikkor is showing a dramatic, visible difference over the Sigma.
Then there’s the bokeh. Neither of them are going to win an award. Onion vs. Donut.
This is not at all uncommon for highly corrected lenses like these.
So, why is the Nikkor so much sharper? I thought it must be field curvature. Ok, no problem. Field curvature isn’t always bad unless you shoot brick walls for a living. It may even be an advantage if you focus-and-recompose. So I focused with live view (like almost all of the samples here) and placed a new focus target towards the edges.
Things aren’t looking good for Sigma at this point, it must be said.
So what did I do then? Drank a beer and went to bed.
Then, the next morning, I woke up bright and early to a poring rainstorm like just about every day in April in Switzerland.
Then suddenly, there was a break in the weather. Out I go! You can’t shoot just charts and boxes I thought. You gotta get out there!
So, using a stable tripod on my nearly-trusty D800, I a couple of landscapes as I’m wandering around the area.
I’ll save you the effort of clicking through, but even at f/11, Nikon wins in an obvious way at near distances and at the edges of the frame.
Ok, I thought, I didn’t buy these primes to shoot landscapes, so let’s go find some more interesting subjects where I can shoot with a narrower depth-of-field.
Don’t ask me what is it about Swiss people and stacking stones, but I quite like the look of this mini cairn against the wet foliage.
Well that’s interesting. Even though the Nikkor is sharper, I prefer the rendering of the Sigma. What’s going on?
Confused, I headed to one of my favourite spots.
Somehow, I quite liked the Sigma image here, although the Nikkor was nearly identical.
I was only able to review the images on the back of my D800 until that point, but even then I was seeing something strange. I had a long walk home to think about the results, but I wanted to review them on the computer before jumping to any conclusion.
Then I did. And it didn’t clarify anything.
It was obvious that the Sigma was as sharp as the Nikon in the centre of the frame at the same aperture but the Nikkor was really ruling around the edges. But sometimes (and always at large apertures) I still preferred the Sigma.
Then I started looking at the shutter speeds. Now, the Sigma is a much more complicated lens, so I expected that the transmission would be lower. (Basically, you lose a little light as it passes through multiple glass elements) But in fact, the opposite was true! The Sigma, at the same aperture as the Nikkor had almost always a faster shutter speed.
What’s going on?
Frustrated, I reviewed the images from the previous night and I had my “AHA!” moment. Now it was all clear.
At the beginning of this review, I showed you the difference in Bokeh between the two lenses. See how the Sigma bokeh balls are larger?Compare the bokeh from the Nikkor at f/1.8 vs. the Sigma at f/2.8. More than a stop difference!
Now it’s clear why I preferred the rendering of the Sigma in some cases. The Sigma actually has a larger aperture than the Nikon at f/1.8! Reviewing my images, I saw evidence of that again and again: Shallower depth of field, larger bokeh and faster shutter speeds.
That is not to say that Nikon is cheating – we’re talking about less than a stop difference. That also can’t entirely explain the difference in sharpness at the edges of the frame where Nikon has a visible advantage. However, consider this 100% crop of the Sigma at f/8 and the Nikkor at f/5.6. Still the Nikkor is a tiny bith sharper, but notice the shutter speeds?
So what am I going to do? I’m going to keep them both. The Sigma shines at narrow depth-of-field photography. It’s beautiful. It has that thing that only Leica people seem to be able to put into words. One must also consider the huge weight difference between the two as well: 665g / 23.5oz. for the Sigma vs. only 305 g / 10.7 oz. for the Nikkor, but that the Sigma goes to f/1.4 instead of just f/1.8-ish.
What will be in my bag every day? The Nikkor, but I’ll be wishing for the Sigma. If I go out for a day of dedicated narrow-depth-of-field shooting like portraiture or some street scenes, you can bet that the Sigma will be weighing me down.
So if I had to buy just one, and my back didn’t mind? Sigma.