Nikkor 35mm f/1.8 AF-S G DX Review

This article will show the lens MTF50 resolution performance and discuss how well the lens autofocuses. Repetition of the Nikon specifications of the lens will be mostly avoided.

This is one of the most popular Nikkor DX “prime” lenses ever produced. It is also one of the most inexpensive lenses; I avoid labelling it “cheap”, since that has a connotation of “low quality”. Nearly everybody will tell you to “just get one”, and with good reason. It’s reasonably fast, focuses well, and provides the natural perspective that equates to the FX “50mm” standard lens.

What you don’t get: vibration reduction and great corner resolution.

My usual disclaimer: this is looking at a single copy of the lens. Yours will be different, but hopefully ‘similar’. The only place I know of that tests lots of copies of lenses is here .

These tests were done using a Nikon D7100 (24 MP) with unsharpened 14-bit compressed RAW format.

Here is a link to get pretty good information on this lens. My main complaint with them (and most of the other web sites) is that they simplify resolution measurement down to a single number for an f/stop. It’s not that simple; resolution is a 2-dimensional thing (not to mention directions within those 2 dimensions).

The focus ring on this lens is a properly wide one, nearest the filter. Just like their ‘pro’ lenses, you can use it anytime you want to override autofocus. This ring is much better than most of Nikon’s kit lenses that have that skinny plastic thing at the end of the lens.

The lens also has a proper metal lens mount and gasket (rubber seal). That’s it as far as dust/weather resistance is concerned.

Annoyingly, there is no distance scale. Not a huge problem, but still it should have one.

Also note: don’t use this lens for infrared; it produces a nasty hot spot in the middle of the field of view in infrared; Nikon’s (even less expensive) 50mm f/1.8 AF-D lens in comparison is wonderful when shooting infrared, and it also is an FX lens. As an aside, Nikon’s 18-55 various kit lenses are all very good at infrared.

Nikkor 35mm f/1.8 DX AF-S with included hood

Autofocus

Fast, repeatable, silent. Enough said.

All of my lenses need some focus fine-tune calibration; so does this lens.

Vibration Reduction (VR)

Nope. Helps keep this lens inexpensive. Even Nikon’s 85mm f/1.4 AF-S doesn’t have VR. Just saying.

Resolution Testing

This is why you should read this article. I won’t mention “good”, “fair”, “excellent” or “blur units” to interpret resolution. I promise. My goal is to enable you to evaluate resolution between lenses in a standard, scientific way. I also give you the information (see my MTF Cliff’s Notes article) to be able to repeat these tests for yourself.

Resolution measurements are in MTF50 lp/mm. This measurement represents how many image line pairs can fit inside a millimeter before the white-to-black chart transitions degrade to 50%; e.g. “turn to mush”. For me, anything beyond about 30 lp/mm is fine, and beyond 50 is outstanding. Higher-resolution sensors yield higher measurements, much like you’d expect.

Before I forget, you will notice a couple of tiny weird blobs in some of the resolution plots that follow (along the top edge). Please ignore these, since they are definitely not a lens imperfection. The measurement software is extremely sensitive, and an imperceptible chart surface indentation shows up very clearly in the measurements. I guess I’ve been doing too many tests and will soon have to retire this chart.

I use a (free!) program called MTF Mapper from here to measure lens resolution. The download site also has files for printing out the resolution targets (mine are A0 size on heavy glossy paper (‘satin’ finish seems to work just as well), dry-mounted onto a board). This program is covered in more detail in another article, but suffice it to say that this is really great stuff; it’s comparable to ‘Imatest’ in the quality of the MTF measurements, and it uses the “slanted edge” technology similar to ‘Imatest’, also. The author of MTF Mapper, Frans van den Bergh, really knows his stuff. Visit his site and give him the praise he deserves.

The chart design used for resolution tests orients all of the little black squares to be ‘slanted’ but they’re generally aligned in meridional and sagittal (think spokes on a wheel) directions to correlate better with the usual MTF plots you’re familiar with. There’s often a dramatic difference in sharpness between these two directions, and the chart photographs show it clearly.

The meridional/sagittal differences are what “astigmatism” is all about. This lens is decent in the sagittal direction when you get away from the lens optical center, and corners are “okay”. Meridional direction is a less rosy proposition, but judge for yourself in the ensuing resolution plots.

The middle of the lens is impressive, as you’ll see.

What the resolution target looks like. Mine is mounted ‘upside down’.

At long last, I’m getting around to some actual resolution results.

Tests were done with “Live View” AF-S autofocus, contrast detect, IR remote, VR OFF, really big tripod. That’s how I get around any phase-detect problems with focus calibration. The results don’t seem to improve using manual focus and 100% magnification in Live View, so I don’t bother. I use the “best of 10 shots”; not every shot gets the same resolution results. All cameras operate on the “close enough” principle for focus, so many tests are needed to determine the best resolution that the lens can produce.