Thursday, March 24, 2022

Nikon 120 f4 Medical Micro: In Depth Review



Tech Specs

Focal Length: 120mm
Dimensions: 5.9” long x 3.9” wide
Weight: 31.4oz.
Maximum Aperture: f4
Minimum Aperture: f32
Diaphragm Blades: 7
Front Element: non-rotating, non-extending
Optical arrangement: 9 elements in 6 groups
    Thread On Attachment: 2 elements in 1 group
Autofocus Mechanism: NA
Closest Focus: 13 inches
Maximum magnification: 2:1 (that’s double life size!)
Filter Size: 49mm

Background
Nikon made its first micro lens for cameras (rangefinder) in 1956: a 55mm f3.5 capable of producing images at half life size. With the advent of the Nikon F SLR system in 1959, Nikon started producing SLR micro lenses by lifting the optics from the rangefinder version and dropping them into a F-mount housing. Nikon's first SLR macro, a 55mm f3.5 (what a surprise!), which came to market in 1961. Shortly thereafter, in 1962, Nikon came out with a 200mm f5.6 Medical Micro that could go up to 3x life size and incorporated a ring flash unit that would more than compensate for the lack of distance (and blocking of light) from lens to subject. The ring flash was powered by a large and cumbersome battery pack. Fast forward 2 decades to 1981. Nikon came up with the model being reviewed here, the 120 f4 Micro Medical. While trading off 3x magnification for 2x, the new lens was powered by a substantially smaller battery pack (8 AA batteries), which made it much more practical for real world usage all while retaining the ring flash. Nikon ceased production of this lens in 1998 and, since then, the highest powered Nikon micro lens only goes to 1x life size. In contrast, Canon produces a truly stunning lens that can go to 5x life size, or powerful enough to fill a full frame with a grain of rice.

 

 

Build Quality
This oldie is built to the typical standards of its time: rock solid as in out of solid metal. Funny how Nikon (and everyone else) is now churning out mostly plastic junk lenses and selling them for thousands of dollars, isn't it? Needless to say, this lens could be used as a weapon if necessary.

Survivability
Good and bad here. With no electronic AF system, this lens should outlast the photographer using it. Unfortunately, this lens does have the ring flash and, after being out of production for 25 years, parts may be hard to come by should something go wrong. If the ring flash were to die, it is very unlikely that a repair could be made, which negates the main selling point of the lens: thanks to the ring flash, available light doesn’t matter. However, the lens is still 100% fully usable, albeit with a lot more difficulty. My advice: if your ring flash were to die, it’s time to invest in a macro lighting system.


AF Performance
This lens has no real focus capability! However, as real macro photographers all know, moving themselves rather than focusing the lens is the way to go. In practice, set the lens to the desired magnification and then move back and forth to achieve focus.



Optics 

Sharpness
Well, there’s no real objective way to test for sharpness as the focal ratio of the lens is tied directly to its magnifying power, unlike traditional macro lenses, like my 200f4 AI Micro. Long story short, with the close up attachment in place, this lens will capture images at .8x life size at its lowest setting while automatically at its maximum aperture f f4. As the magnification goes up, so does the focal ratio. By the time the lens reaches its maximum magnification of 2x life size, it has stopped itself down to f32. As anyone familiar with photography knows, a lens will, at some point, hit what is called the diffraction limit, which is just a fancy way of saying that, come a certain f-stop, the sharpness of the lens will actually start to decrease rather than increase. Generally, most lenses peak in overall sharpness across the frame from f8 to f11, after which the sharpness will actually start to decrease. For anyone who has made it through all of this technical mumbo jumbo to this point: this lens is not at its sharpest at 2x life size, its main selling point. However, this is more than offset by the fact that this lens can to to 2x life size at all and, as seen in the samples below (all taken at 2x life size), it looks pretty doggone sharp.

Macro:

This lens focuses down to 2:1, or double life size when used with the thread-on close up adapter, otherwise it focuses to ‘just’ 1:1, which was already double the native magnification of any contemporary Nikon micro lens.


See also: Half vs. Full vs. Double Life Size: how big is the difference?


Astrophotography
Forget it, there is no infinity focus.


CA
Can’t see any even in extreme lighting conditions (thanks to the ring flash).


Value
Where else can you get a Nikon micro lens that goes above 1:1 magnification? Nowhere, save the older 200 f5.6, which I have never seen anywhere on the used market. On the other hand, the trade offs that went into making this lens almost a microscope have a price, namely that this lens can only do micro and nothing else. Any other micro lens can also be used for any other photographic purpose to varying extents. This lens? Nope, it’s a one trick pony but, the one trick that it does do, it does extremely well.

Competition
To put it plainly, there isn’t any competition besides the already mentioned 200 f5.6 Medical Micro, which can go to a whopping 3x life size. On the other hand, 1:1 macro lenses can be made to go to 2:1 by extension tubes, but all of these will create the same problem: namely blocking one’s available light, which is a non issue here thanks to the built in ring flash. On the other hand, any other traditional macro lens will be much easier to use.

Samples

 
Book pages.


 
Camera case foam


 
Cat claw husk


 
Cheerio


 
Hair brush bristle


 
Hand towel


 
Japanese beetle


 
Metal nail file


 
My wrist


 
Pencil point


 
Pencil eraser


 
Pool cue scuffing tool


 
Quarter edge


 
Quarter


 
Rag


 
Razor blade


 
Newsprint standard size



Speaking of easier to use . . .

While any experienced photographer can usually just take a lens out of a box, pop it on the camera, and start making pictures, such is not the case with the 120f4 Medical Micro. This being a film era lens (when changing ISO mid-shoot was not an option), there is actually a 24 page manual on how to use this lens. While not a huge read by today’s standards, for 40 years ago, this was a big deal.

As for my experience with this lens, I can’t comment on everything in the manual for the simple reason that my lens didn’t come as a full kit. What I do have are the DC power unit (powered by 8 AA batteries) and the 3 pin flash sync unit, which mounts into the camera’s hot shoe.

The book starts out with the most basic operation: mounting the lens. If you’re reading this, I’ll assume you know how to mount a Nikon F-mount optic. . .

The next few pages of the book deal with the power options. In my case, this is limited to the battery powered DC unit and the 3 prong sync cord, which plugs into the lens on one end and then goes into the camera’s hot shoe on the other.

The next step is vitally important if you’re shooting film, as it’s a must to set the film speed on the lens as the output of the flash is directly tied to the film’s ISO rating. Higher ISO, weaker flash. Lower ISO, stronger flash. In practice, the ISO setting ring is held in place by a screw. To move the ring, loosen the screw and adjust the ring accordingly. For the young macro shooter, it may come as a surprise to see that the highest ISO setting on the ring is for 800. Yep, back in the day, ISO 800 was really pushing the limits of film technology.

Next section of the book, the shutter speed setting, is largely out of date unless you are using an old film camera, which will have optimal settings outlined in a handy chart.

The next couple pages of the manual deal with focusing and setting the magnification.

The next section deals with mounting the close up adapter. Itself, the 120 f4 Medical Micro has a magnification power of 1:1 but, with the adapter, it goes to 2:1, or double life size. In practice, I had a hard time threading the adapter onto the lens, no doubt to at least 25 years of adding/removing it and the resultant worn threads. In the product shots in this review, the adapter is always on the lens. A table of reproduction ratios, focus distances, depths of fields, and subject field sizes follow for with and without the adapter.

Next up: a very cool feature for early 80s technology: magnification ratio imprinting on the image. To record your magnification on the image, simply press the ‘data’ button and go.

The next page deals with using the lens with the ring flash turned off, which can really come in handy if your ring flash were to die.

Next up: how to operate the focus assist lamp in situations with dim lighting. Unfortunately, you may be out of luck in locating a replacement bulb come 2022 if yours were to burn out.

The next point is moot unless you have a film camera or a newer digital one, recommended focusing screens. As someone who has shot an old film camera (a Canon FT QL), the old pre AF cameras were much easier to manually focus than the new ones, and anything to make focusing easier should be utilized because, at 2x life size, to call the depth of field razor thin is putting things mildly.

The book wraps up with a few pages about cautions (remember, this lens is electronic), lens care, recommended accessories, and tech specs.


Conclusion
If you’ve made it this far into this review, you want this lens as there's no other lens offering such a combination of high build quality, optical excellence, insane value, and not to mention greater than 1:1 magnification as this one, save the 200 f5.6 Medical Micro, which I have never seen on the used market. Sure, you can pay a lot more for a current macro lens for AF capability, stabilizers and ‘only’ 1:1 magnification but real macro photographers don't use AF. On the other hand, the real problem comes via its strength: it does great micro, but that’s all it can do and if the flash unit were to go bad, you might be out of luck for getting it repaired. Bottom line: if you’re very serious about micro photography and have to go beyond 1:1 power, this lens is for you. For anyone else (namely casual micro shooters, beginners, or anyone not wanting to go beyond 1:1), any more traditional optic is the way to go but, if you’re really big on making small objects look huge, this is the optic for you and don’t wait around if you’re lucky enough to come across one, they don’t come up often or last long when they do pop up on the used market!



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