I am new to photography (just 3 to 4 months of experience) and I am looking to buy a new lens (either 35mm or 50mm, but mostly 35mm because I have already decided Sigma 85mm f/1.4 DG HSM Art Lens for the creamy bokeh) for general street photography.

I like my images to be as sharp as possible. I went through many websites and youtube videos and many of them mention that Nikon 1.4g is superior to Nikon 1.8g. At the same time they also mention that Nikon 1.8g is sharper. why is Nikon 1.4g better when Nikon 1.8g is sharper ?

1) Sharpness is complicated.

Lens sharpness is just one aspect of the overall resolving power of a camera system. The appearance of crispness is separate from the rendition of detail. And a lens can be sharper in the center but not in the corners, or less sharp overall but consistent across the frame.

And that's not even getting into other factors that affect the system as a whole. Camera shake, subject movement, focus accuracy, diffraction — the list goes on. In fact, I'd go so far as to say that unless you are very meticulous with your technique, you won't ever notice a sharpness difference between these lenses, because any lens difference will be overwhelmed by the other things.

2) Sharpness is overrated.

It's fine it like it, but recognize that sharpness is just one aspect of optical performance. All lens design is about compromise between various factors, and correction for one thing inevitably leads to compromise in another. See What image-quality characteristics make a lens good or bad? for a detailed look at this. Generally, though, when someone is saying that a lens is better than another even though the other is sharper, some of these other factors are probably at the forefront.

3) Don't forget that extra speed.

An f/1.4 lens can stop down to f/1.8. An f/1.8 lens can't open up to f/1.4.

What did the reviewers say about why they chose one lens over the other?

They have their own priorities and biases. You should evaluate the information they present and decide for yourself whether you agree with their conclusions.

Everyone tests lens sharpness because it's easy. Just photograph a resolution chart and read off the numbers. However, this method really tests lens-camera combinations.

• Beyond a certain level of sharpness, most pixel peepers should be satisfied. For me, around 65 lp/mm is "good enough". A lens that is at least that sharp gives me plenty of detail to work with in real images that are not of resolution charts or brick walls.




• The difference in sharpness among lenses that exceed sensor capabilities makes no difference to final image quality.

I have two 35-105/3.5 zoom lenses from the 1980s that are quite sharp. The sharpness results are maybe too good and I wonder if I read the chart wrong. Regardless, modern lenses still look just a bit better. (Imagine these are 1"x1" crops from 40"x27" images.)

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  Canon EF 24-105/4L @ 24/4

  
  
  

  

  
  


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  Nikon 24-120/4G @ 24/4 -and- Nikon 24-70/2.8E @ 24/2.8

  
  
  

  

  
  


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  Pentax-A SMC 35-105/3.5 @ 35/3.5 and 35/4.5

  
  
  

  

  
  

There's more to lenses than sharpness.

• veiling glare



• contrast




• flare ghosts



• focal lengths, zoom range



• max apertures – variable vs constant




• distortion



• chromatic aberration


• bokeh (quality)


• close focusing / macro mode



• color rendering




• technology – autofocus, image stabilization, etc.

How you prioritize these factors can result in a completely different lens being "better" for you than for me or anyone else. For instance, I'm much more concerned about veiling glare, than distortion and chromatic aberration. As long as distortion and CA are not out of control, they add "character" to images. But terrible veiling glare can make images useless.

Recently, my sharpest, most advanced lenses have become among my least used lenses. Consider XF 18-135/3.5-5.6 R LM OIS WR. It's an excellent lens by any measure. I consider it an excellent lens, superior to my current favored lens, but it's not suitable for what I want.

1. I want the short end to be longer (~28mm).


2. I want constant F3.5 or faster variable aperture (2.8-4)


3. I want closer minimum-focusing distance.


4. I want bokeh with "character".