Nikon Nikkor-T 10.5cm f/4: Nikon's Unique 105

Ching-Kuang Shene

Created June 5, 2014

Original Chinese Version: October 29, 2008

Images here are used to illustrate some characteristics of a lens rather than showing my personal artistic point of view.

The Nikon 105 was a very well-known SLR lens in the film era and is the synonym of the Nikon 105mm f/2.5. Nikon made this SLR lens for more than four decades with only two major types, the Sonnar (early) type and the Double-Gauss (later) type. Most manufacturers prefer to make the 90mm or 100mm versions and Nikon is one of the very few lens makers choosing to go with 105mm.

Nikon launched the 105mm f/2.5 in 1959 for Nikon F, followed by 105mm f/4, 105mm f/1.8 and 105mm f/2 DC. Even the micro lenses are also 105mm, namely 105mm f/2.8, 105mm f/4, Bellow Nikkor 105mm f/4 and UV Micro Nikkor 105mm f/4.5. In fact, only the cheap Nikon 100mm f/2.8 Series E is in 100mm. By the way, the Series E 100mm f/2.8 is a very capable lens.

The fame of the 105 was more or less due to the Vietnam War era correspondents, who found the 105mm f/2.5 to be a cheaper and very capable short telephoto portrait lens. Personally, I always felt that the 105mm performs better than the 135mm and am not used to the 85mm. As a result, right after I started playing with SLRs, I chose the 100mm and 105mm as my standard portrait lens. Throughout the years, I acquired the 105mm (not the micro versions) one after the other; but, I had never thought about the Nikkor-T 105mm f/4 because its performance is not as good as the 105mm f/2.5 and because it has a smaller aperture of f/4 rather than f/2.5, f/2 or even f/1.8.

Since the entire Nikon 105 system includes so many lenses each of which also has a number of variations, it is very difficult to discuss all 105mm lenses in one article. So, I chose to start in a modest way with this uncommon Nikkor-T 10.5cm f/4 and leave other 105mm versions to future articles.

Background Information

Before announcing the Nikon F in 1959, Nikon made rangefinder cameras and lenses. Because there was already a good RF version of the 105 when Nikon launched the Nikon F, Nikon offered the BR-1 and N-F adapters for the Nikon F body to use some RF Nikon lenses. Between 1959 and 1960, Nikon released the first batch of F-mount lenses: Nikkor-Q 2.1cm f/4 (a Carl Zeiss Biogon type lens, but requiring mirror lock-up and an external viewfinder), Nikkor-H 2.8cm f/3.5, Nikkor-S 3.5cm f/2.8, Nikkor-H 5cm f/2, Nikkor-S 5.8cm f/1.4, Nikkor-P 10.5cm f/2.5, Nikkor-T 10.5cm f/4, Nikkor-Q 13.5cm f/3.5, and Nikkor Telephoto-Zoom 8.5-25cm f/4-4.5. The Nikkor-P 10.5cm f/2.5 is the most well-known one.

Of these lenses, the most puzzling one is the Nikkor-T 10.5cm f/4, which was produced in March 1960. The well-known Nikkor-P 10.5cm f/2.5 is able to perform the AUTO function even in its first version. The AUTO function, in Nikon's terminology, means that the aperture is always open for focusing and metering and automatically closes down to the shooting aperture when the shutter release button is pressed down to take a photo. If Nikkor-P 10.5cm f/2.5 is such a capable lens, why did Nikon make a smaller aperture 10.5cm without the AUTO function? The full story may never be known. Maybe Nikon just wanted to make a cheaper but high quality lens that performs similarly on RF and SLR cameras. Or, maybe Nikon had learned something from Leica Elmar 105mm f/6.3 (usually referred to as the Mountain Leica). At least, some Leica fans believe this is perhaps the story. However, since the Mountain Leica is a pre-war short-lived product (1932-1937) and Nikkor-T 10.5cm f/4 is a post-war lens, comparing Nikkor-T 10.5cm f/4 against Mountain Leica seems to be a bit far-fetched. Maybe we should compare Nikkor-T 10.5cm f/4 with Leica's Elmar 90mm f/4, a well established lens for several decades. As a matter of fact, due to the success of the Nikkor-P 10.5cm f/2.5, Nikkor-T 10.5cm f/4 survived on the market for only three years, even shorter than that of the Mountain Leica. This explains why Nikkor-T 10.5cm f/4 is not easily found.

The first image below shows three lenses, from left to right, Nikkor-P 10.5cm f/2.5, Nikkor-T 10.5cm f/4 and Leica Elmar 90mm f/4. The second image shows the two 10.5cm lenses.

Each of the non-zoom lenses announced in 1959 has a letter appended to Nikkor-. This letter indicates the number of glass elements used in the lens construction as shown in the table below. Therefore, Nikkor-T 10.5cm f/4 means this lens uses three glass elements, a very typical Triplet design.

The Lens Nikkor-T 10.5cm f/4

The following image is a Nikkor-T 10.5cm f/4. This lens has a slim lens barrel. The front of this lens has the aperture markings, followed by two rings for setting the aperture to be used, followed by a focusing ring and depth of field scale. The bottom portion has a Nikon F-mount.

The left image below has the inner front rim. It shows that this lens has three glass elements and focal length of 10.5cm with maximum aperture f/4. The right image below shows the aperture range being f/4 to f/22.

The Nikkor-T 10.5cm f/4 uses two rings to set aperture. The ring right below the aperture markings has a white line. Turn that ring so that the white line aligns with the f-value to be used, f/8 in the left image below. This sets the shooting aperture; but, the aperture blades do not close down at this point. The second ring has a small white dot and is used to close down the aperture blades. The right image below shows the aperture blades are closed down to f/8. Therefore, the user sets the aperture to be used with the first ring for focusing, and before shooting the user closes down the aperture to the set aperture with the second ring for metering and focusing. Note that the small white dot can stay at any position and cannot be moved passing the position set by the white line. This means that even though the user may set the aperture to f/8 with the first ring, s/he may use a larger aperture than f/8 set by the white line. The aperture ring has half-stop clicks, but the user may stop anywhere between two clicks. Furthermore, pulling the first ring downward (toward the rear of the lens) and turning it cause both aperture rings to turn simultaneously and at the same time changes the shooting aperture.

The following image below shows an early Nikkor-P Auto 105mm f/2.5 on the left and a Nikkor-T 10.5cm f/4 on the right. It is easy to see the following differences:

  1. The last glass element of the Nikkor-T 10.5cm f/4 is deeply recessed into the lens barrel.
  2. There is no rabbit ear (marked in blue) on the Nikkor-T 10.5cm f/4. The rabbit ear is a mechanism prior to the AI era used for transferring the aperture being used on the lens to the meter built into the camera body. As a result, the camera body does not know what shooting aperture will be used by the Nikkor-T 10.5cm f/4 and one must use stop down metering and shooting.
  3. There is no automatic diaphragm pin (marked in yellow) on the Nikkor-T 10.5cm f/4. This means one must close down the aperture before shooting.
  4. There is a ridge around the bottom of the Nikkor-P Auto 105mm f/2.5, meaning this lens is not usable on most modern Nikon SLR/DSLR bodies that have the AI mechanism. To use this type of pre-AI lenses, one must modify the rear of the lens (i.e., AI'd). Since the bottom of the Nikkor-T 10.5cm f/4 is flat without the ridge, it can be used on all Nikon F-mount camera bodies with a F-mount, DSLR included.

Here is the Nikkor-T 10.5cm f/4 mounted on a Nikon D70. The lens looks small.

Some Examples

The following images were taken using a Nikon D70 with the Nikkor-T 10.5cm f/4 set to f/4, f/5.6, f/8, f/11 and f/16. The smallest aperture f/22 was not used. The purpose of these images is investigating subject separation by various apertures. The distances from the subject and background to the camera are about 6 meters and 8 meters, respectively. It was a cloudy day and sun light was not uniform. As a result, exposure cannot be kept uniform. It seems that f/4 and f/5.6 are able to separate the background from the subject nicely, and that even f/8 the lens can do a good job. In the last two images taken with f/11 and f/16, a hint of the double-line effect can be seen, which means bokeh may not be excellent. The double-line effect in background or foreground will be more obvious in a high contrast scene.






In my opinion, color rendition of the Nikkor-T 10.5cm f/4 is in the cold side and not very saturated. This could be a combined result of the lens and the Nikon D70. Contrast is also a bit low, especially that flare can show up at f/4 perhaps due to internal reflection. Increasing the image contrast and saturation in post-processing may be very helpful.

In the following two images, contrast is still not high and color rendition is on the "light" side.

It was autumn and rainy while writing this article. Eventually, the sun showed up for a few moments for me to snap some images of autumn leaves. Color rendition is still on the "light" side.

Bokeh, etc.

It is hardly to ask for a f/4 lens to have an excellent performance on the bokeh front. But, this Nikkor-T 10.5cm f/4 is not bad at all. The following image was taken by pointing the lens to an area full of out of focus bright spots. As you can see, each out of focus spot is a solid circle with a very narrow and slightly brighter circumference. This suggests that the transition between bright spots would be smooth enough and that even though there could be some sign of double-line effect the impact would not be great.

The following shows four more examples. A common characteristic is that a small aperture lens could not dissolve overlapping out of focus spots enough to produce a silky smooth background. In the first and third images, the out of focus spots overlap but are not dissolved sufficiently, and, as a result, the background looks a bit distracting. The fourth shares the same characteristic. The third image has a slight double-line effect around the outline of the out of focus house.

Nikkor-T 10.5cm f/4 lens was not multi-coated and easy to produce flare. In the image below, the sun is located at the upper right corner and is outside of the image. Except for the lower right corner, most area in the image is affected and has lower contrast.

Some Thoughts

The Nikkor-T 10.5cm f/4 is not my favorite lens. While it is not as good as the Nikkor-P 105cm f/2.5, it is not as bad as some criticisms circulating for years. If the Sonnar version of Nikkor-P 105mm f/2.5 is rated at 100%, IMO this Nikkor-T 10.5cm f/4 could still be as high as around 80%. Please do keep in mind that the Nikkor-T 10.5cm f/4 is a Triplet design (i.e., 3 elements in 3 groups) usually used in cheaper lenses such as the Meyer Trioplane 100mm f/2.8, Carl Zeiss Jena 85mm f/4 Triotar and Carl Zeiss 135mm f/4 Triotar. As far as I know, the only expensive Triplet lens is the Leica 3-element Elmar 90mm f/4.

In my opinion, at f/4 the Nikkor-T 10.5cm f/4 is not as good as the Nikkor-P 105mm f/2.5. Image quality between f/5.6 and f/11 is quite uniform. I am not sure if this is only me, but I do feel the Nikkor-T 10.5cm f/4 paired with Nikon D70 always produced colder color and lower contrast. Some believe this may be due to internal reflection, but I do not have a solid proof if this is the main cause. Even at a small aperture, say f/8, this this lens still produced slightly washed out results just like the Meyer Trioplane 100mm f/2.8. On the other hand, the 3-element Leica Elmar 90mm f/4 seems to be better or much better. Anyway, more testing may be needed to find out the cause.

To many SLR/DSLR users, this lens requires some getting used to because the way of setting aperture and the way of metering. Once you become familiar with to these operational issues, the Nikkor-T 10.5cm f/4 can be a very competent company for casual shooting as it is light and small.

Finally, if you love to playing or collecting legacy lenses, the Nikkor-T 10.5cm f/4 may be a good choice. Otherwise, if you just admire the name Nikon 105 and wish to have a 105 to shoot portraits, I would think you should get a AI-S version of the 105mm f/2.5 because of lower price and higher quality. If you wish to use the best of the 105s, you'd better be prepared to spend more money on a AF-D 105mm f/2 DC because it will not let you down. To sum up, as long as optical quality and price are major concerns, the AI-S is the preferred version of the 105mm f/2.5. As for collecting, the RF version of the Nikkor-T 10.5cm f/4 (with hood , lens cap, filters, case, etc.) should be a good choice. Otherwise, this F-mount Nikkor-T 10.5cm f/4 should be OK. If you have a limited budget, the Nikon 100mm f/2.8 Series E is undoubtedly the best choice, because it is cheap and has respectable quality.

The image below shows four Nikon 105 lenses. From left to right, they are the earliest Nikkor-P 10.5cm f/2.5 (1959, the tick-mark version), the Nikkor-T 10.5cm f/4 (1960), the AI-S 105mm f/2.5 (1981), and the AF-D 105mm f/2 DC (1993):


The following are the specifications and the optical construction of the Nikkor-T 10.5cm f/4:

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Created: June 5, 2014
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