|Sean Carpenter | profile | all galleries >> Equipment >> the Normal Lens Shootout >> Round 1 >> Match 4: (5) Nippon Kogaku Micro-Nikkor Auto 1:3.5 f=55mm vs. (12) SMC Pentax-M 1:1.7 50mm||tree view | thumbnails | slideshow|
The two lenses in this comparison, the 5th-ranked Nippon Kogaku (Nikon) Micro-Nikkor Auto 1:3.5 f=55mm and the 12th-ranked SMC Pentax-M 1:1.7 50mm, are as different as any other two lenses in the starting round. The Nikkor is made for 1:2 macro magnification and is relatively slow at f/3.5 maximum aperture, while the Pentax is made as an inexpensive low-light normal lens. As such, it was somewhat difficult to rank side-by-side since the usual function for these lenses doesn't overlap; the Nikkor is not very useful in low light and the Pentax is not very useful for macros. I tried to find some middle ground for each, as well as deciding how good each was in its respective role.
The Pentax-M 50/1.7 is a compact and light lens, at 185 grams it is only 25 grams heavier than the smallest lens in this shootout. It is made from the same materials as most M-series lenses, with a metal barrel and rubber focus ring. The build quality for this lens is better than the SMC Pentax-M 1:2 50mm in
The Micro-Nikkor 55/3.5 is an all-metal lens, with a scalloped focus ring but simple notched aperture ring. It is still a very light lens, at 235g, but it is much larger physically than the Pentax. This has an overall effect of making the Nikkor feel almost hollow in your hand and on the camera. The focus throw on the Nikkor is smooth, but has more of a paper-sliding-on-paper feel. The aperture ring works fine, with definite clicks at each half-stop, but the ring (and the click) is softer than comparable Pentax lenses.
The Pentax-M 50/1.7 shares a 6-element, 5-group design with the other Pentax 50/1.7 lenses, and focuses down to about 0.45 meter for a maximum magnification of 0.15x. The Micro-Nikkor 55/3.5 is a 5-element, 4-group construction and on Nikon bodies it can focus to 0.25 meter. The focus distance is slightly altered when mounted on the Pentax because the lens-to-film distance is different between the models.
The Micro-Nikkor 55/3.5 is obviously not intended for use on a Pentax K-mount camera, but as I've discovered the Nikon F mount fits flush within the Pentax K mount. For two of my other Nikon lenses, I've removed the F mount and replaced it with a K mount. This lens, however, is unmodified; because of its size, shape, and weight, it fits cleanly on my Pentax bodies. I primarily use the Nikkor 55/3.5 as a macro lens, so I have in fact converted a set of extension tubes to have a Nikon F mount on the lens side and a Pentax K mount on the camera side. For the purposes of this comparison I did not use the extension tubes.
One of the problems with this and other stop-down-only macro lenses is that in order to maximize depth of field, they often must be used at apertures too dark to effectively focus. This leads to sometimes missing accurate focus, especially with bugs and other fast-moving objects.
The Pentax-M 50/1.7, like the
Side view of both the Nippon Kogaku Micro-Nikkor Auto 1:3.5 f=55mm, left, and the SMC Pentax-M 1:1.7 50mm, right.
This shot demonstrates both the positives and negatives of the Pentax-M 50/1.7. It is tack sharp, but the distracting aperture blades draw your attention away from the penguin.
Macro lenses are generally lauded for their sharpness. At like-sized apertures and distances though, the little Pentax-M 50/1.7 performs every bit as good as the Micro-Nikkor 55/3.5. The Pentax-M 50/1.7 appears to have more contrast, giving an impression of being even sharper, like in the samples of the hydrangea or in the crops of the guitar. For my needs, both of these lenses are perfectly sharp, and I'll even give the edge to the Pentax.
Here is where the Micro-Nikkor 55/3.5 competes in another league compared to the Pentax-M 50/1.7. Its close-focus capability transforms otherwise ordinary scenes. The close-focus comparisons demonstrate this - the same shot rendered by the Pentax-M 50/1.7 is here whereas the Micro-Nikkor 55/3.5 is here.
If both lenses performed admirably for sharpness, neither gets flawless marks for bokeh.
The Pentax-M 50/1.7 shows considerable axial color (green or purple rings inside out-of-focus objects) at f/2.8 and wider. It has unevenly-bright highlighs, with typical bright rings around specular highlights. It also suffers from its 6 straight aperture blades, which serve to distract heavily in shots like this one. Certain shots show an atypical (for Pentax lenses) bokeh, as in this shot, which looks like the out of focus area is wrapped in plastic wrap.
The Micro-Nikkor 55/3.5 also suffers from its 6 straight aperture blades, although it does not exhibit as much axial color as the Pentax-M 50/1.7 and has a more evenly lit blur disk.
This matchup compared two distinctly different lenses. The Pentax-M 50/1.7 has a tremendous low-light advantage, and the Micro-Nikkor 55/3.5 has a similar advantage in magnification. They both get high marks for sharpness, although that's about it. Determining which one is better, for me, comes down to how good each lens is in its respective segment.
To that end, the Pentax-M 50/1.7 is a capably-sharp but otherwise flawed low-light lens. They Micro-Nikkor 55/3.5 is a decent but not perfect lens, especially when used on a Pentax and without extension tubes. The Pentax-M 50/1.7 is poorly implemented on modern Pentax bodies, with the Micro-Nikkor 55/3.5 ironically being a notch easier to use. It is the Pentax-M 50/1.7's bokeh (and the 6-straight blades) that keeps me from selecting it over the Micro-Nikkor 55/3.5. While certainly usable in most circumstances, the Pentax-M 50/1.7 doesn't deliver in demanding low-light situations enough to warrant continuing in the challenge.
As an end note, neither of these lenses was as good as I had hoped. This turned out to be a battle of okay, but not exceptional, lenses.