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Nikkor-P C 105mm f/2.5 Review

April 7, 2016

This is a pre-AI model, and was tested on the D5000, which Nikon specifically states is incompatible with this camera.  Hmm.

 

This lens was the reason many people bought Nikon.  In its day, it was the portrait lens to get.  I remember Linda McCartney using this lens to take pictures of Paul in a televised concert.  It’s my understanding that she could afford to use whatever she wanted, seeing as her husband was already a near-billionaire at the time.  This lens version had anti-reflection coating (the "C" in the lens designation).

 

This is another lens that was used in the making of the original Star Wars movies.

 

The MTF50 measurements presented below, being produced from a 12MP camera, don’t look as high as more modern high-resolution sensors.  This lens won’t fit my other cameras, and isn’t one that can be updated to “AI”, either.

 

 Focus

 

Silky smooth, but totally manual. 

When you could get cameras with split-prism focusing screens, focus was a breeze.  With cameras these days, manual focusing is a lot tougher.  Such is progress.  I had thought the D5000 “rangefinder focus” would be the answer, but it won’t work for these manual lenses. Oh well.

 

Nikkor-P C 105mm f/2.5 with HS-4 hood on D5000.  An elegant lens.

 

 

Resolution Testing

 

These tests were done using a Nikon D5000 (12 MP) with unsharpened RAW format.

 

Resolution is a 2-dimensional thing.  The tests that follow show you how resolution varies throughout the frame.

 

Also, the sagittal direction is really, really good.  The meridional direction isn’t as good, but is still better than most lenses.

 

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 my MTF Mapper Cliff’s Notes article. The software is comparable to ‘Imatest’ in the quality of the MTF measurements, and it uses the “slanted edge” technology similar to ‘Imatest’, also. I can’t thank the author of MTF Mapper, Frans van den Bergh, enough.  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.

 

If you spot some small islands of resolution peaks/dips in the following charts, you can safely ignore them.  Visually imperceptible variations in the surface of the resolution chart can show up rather dramatically in the plots, because the analysis software is exquisitely sensitive.

 

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

 

Finally, I’m getting around to some actual resolution results.

 

 

Tests were done with “Live View” manual focus at maximum magnification and IR remote. I use the “best of 10 shots”; not every shot gets the same resolution results.

 

Corner, wide open at f/2.5 target squares cycles/pixel. Sagittal beats meridional.

 

 

Center, wide open at f/2.5 target squares cycles/pixel.

 

 

 

 

 

 

 

 

 

The corners aren’t really good until f/4.0, but the center is terrific at all apertures until a little beyond f/16.

 

You don’t want to use f/16 or beyond if resolution is important to you.  Diffraction kills sharpness.  I didn’t bother to measure, although this lens lets you set the aperture all the way down to f/32.

 

The resolution of this lens leaves almost nothing to complain about.  The corners, which are a “don’t care” nearly all of the time for most people, need f/4.0 or more.

 

Conclusions

 

If you’re a “manual” kind of person who likes to be in charge of what is going on, then this just might be the “it” lens for you.  Bear in mind that the lens mount doesn’t permit being mounted on the latest Nikons, and this version cannot be “AI converted”.  I have always enjoyed using this lens for portraits, and it gives you enough working room that your subject is invariably more at ease.

 

You can’t exactly quantify it, but this lens just feels right.

 

 

Sample Picture

 

Crop from a head shot.  The eyes tell the story of this lens.

 

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