With an oblique view: the amazing 85 mm f/2.8 PC Micro-Nikkor
By Bjørn Rørslett
Review incepted 11 November, 1999
Long awaited, my 85 mm f/2.8 tilt/shift Nikkor finally arrived yesterday. Basically, the 85 PC is a lens Nikon should have launched years ago. For some inscrutable reason, Nikon only offered shift-capable 28 mm f/3.5 and 35 mm f/2.8 PC lenses (PC = Perspective Control). True, the design of the 35 SLR camera prevents a wide range of lens movements so tilt/shift (TS) lenses potentially are less useful for this format than in medium and large-format systems. In practice, they however can be immensely useful and help solve a number of picture-taking problems. Any shift or tilt movement is better than none, and at least for landscape and large-scale work, just small movements are needed to nudge the plane of focus into the wanted position. I own the 28/3.5 and 35/2.8 PC Nikkors, plus a Canon TS 35 mm f/2.8 which is modified for using on Nikons. Years ago, I rebuilt my 28 PC Nikkor to make it possible to use it with full shift and tilt. This modification gave stunning image possibilities. Yet, many pictorial applications called for a longer lens. In some cases, I have improvised using my Bellows-Nikkor 105mm f/4 on a tilt/shift bellows unit made by Hama of Germany. However, this setup was very awkward to operate in the field and the quality of the Hama bellows is questionable. So, the news about the upcoming tilt/shift Nikkor were like a dream coming true and the fact this is a Micro lens suited me even better ...
I had studied specifications of the 85 mm f/2.8 PC for some months now, ever since its launch in Mid June, but still was not prepared for the 'real thing'. 85 PC is sheer brute force. Thus, the 85 PC is twice the size and price of the Nikkor 85 mm f/1.4 AD, which isn't exactly a small and cheap lens in it self. The external finish of the lens barrel compares to that of the AFS 17-35 f/2.8 and has a quite smooth hammered surface. However, although it is a beast of a lens, the weight is not commensurate with its size and in fact it weighs about the same as the f/1.4 lens. This results because of its low speed. It features a modified double-Gauss design with 6 elements in 5 groups. It focuses directly to 1:2 (half life-size) and reaches nearly 1:1 when the PK-13 ring is added. As usual these days a 77 mm filter thread occurs.
Apertures range from 2.8 to 45 and are set with a substantial ring at the middle of the lens barrel. There is a soft-working plunger for giving stopped-down metering with the lens. Incidentally, it is a manual 'D' type lens that conveys the focused distance and the effective aperture to the camera. A nice touch for anybody using a hand-held meter. Nikon says plainly that the light meter on the camera will not show correct values when the lens is shifted or tilted, and suggests a correction of the meter reading within a ± 1 stop range. This is keeping in common with the erratic behaviour of TS lenses on any SLR (Nikon, Canon) that meters TTL, simply because the TTL system presupposes the light cone emanating from the lens be parallel to the optical axis. And in the case of a tilted or shifted lens, this doesn't hold anymore and thus the meter is fooled. The proper method is to measure with the lens set to zero movements, lock the exposure reading and then move the lens into the correct shooting position. Yes, this procedure do slow you down, but it still is much faster than working a large-format view camera. According to my test shots, a correction of -1 stop from the camera meter reading was necessary when the lens was shifted to its extreme limits. Obviously, smaller corrections would be appropriate for intermediate levels of shifting. When I only tilted the lens, the readings given by my F5 deviated less than 0.5 stop from the values obtained with the lens in a neutral position. Smilar results were obtained with the D1.
The front element is deeply recessed in a manner similar to the 55 mm Micro-Nikkors, which also feature quite similar optical designs. A dedicated sunshade is to be bayoneted to the front of the lens, but this wasn't yet available when I got my 85 mm lens. Likely a lens hood is only needed if a filter is attached, and because of the tilt/shift capabilities of the lens, any shade would have to be quite wide (and less effective) so as not to vignette the image. Evidently the 85 PC is above average as far as its resistance to flare and ghosting is concerned so lack of a lens shade isn't critical anyway. I found that the shade from my 85mm f/1.4 AF could be used if some precautions were taken at the extremes of the tilt range. This saved the day, by keeping the front element clear, when shooting in chilly downpours and winter blizzards.
As delivered, the 85 PC has its shift and tilt movements orientated at right angles. This is incidentally the same way Canon TS lenses are set up. While this design possibly can be advantageous for tabletop and studio work, it is not optimal for nature and landscape photography. Fortunately, Nikon stated in their leaflet that the movements could be made to work in parallel. Not willing to wait for this modification to be carried out, and uncertain about the non-specified surcharge for doing this, I soldiered on to make the change myself. It took just 5 minutes using a small screwdriver and a pair of pliers. Thus I ended up with my 85 PC working literally in parallel to my other TS lenses. I have since modified a couple of other 85 PCs and noted that the modification may be a bit tricky on some of them. If in doubt, hand the lens over to the nearest authorised Nikon repair facility.
The 85 PC delivers a pleasantly 'rounded' view in the camera's viewfinder. This results because of its nice 'bokeh', that is, the out-of-focus parts of the image is rendered with considerable softness. The diaphragm operates with 9 blades so as to make the shooting aperture virtually circular. Moreover, the optical design itself obviously contributes to the pleasing effects obtained with the 85 PC.
I tested the 85 PC using my routine setup as outlined under the 'Lens Evaluation' section. Commencing with this lens, I now intend to summarise my results graphically as depicted in the graph below. The graphical presentation aims to augment, not replace, the exhaustive written comments on each lens. Please bear in mind that no lens can achieve an 'Outstanding' or 'Excellent' quality when it is stopped well down because of the adverse effects of diffraction. Performance at each aperture in this graph is not weighted according to the maximum possible, so any lens will show a declining pattern towards its minimum aperture. I simply evaluate the test results in terms of what one should like to see in image quality, were the aperture setting not known.
|Subjective evaluation of the 85 mm PC Micro-Nikkor. See text for details.|
The 85 PC is slightly soft across the entire frame wide open. This evidently results from internal flare, which disappears by f/4. More noticeable is its virtual lack of vignetting into the corners even set wide open, a feat very few lenses can match, and the inevitable drop in sharpness towards the corners is scarcely perceptible. When the lens is shifted to its maximum, the extreme corners just show the slightest trace of softness, so image quality obviously extends all over the projected image circle.
Image contrast and sharpness improve rapidly upon stopping down, and within the peak range f/8-f/11 the image results are simply stunning. There is no trace of colour fringing and this adds to the impressive image quality. Linear distortion is entirely negligible over the field of view, although to be nit-picking, diminutive vestiges of pincushion distortion possibly can be detected along the edges of the image frame. For actual picture-taking this can safely be ignored - straight lines will continue to be straight when captured by the 85 PC.
The remarkable image quality of the 85 PC holds up much longer than usual when the lens is stopped down. I regard the lens as being diffraction-limited in its performance from f/11 and beyond. Even at f/22, very good results are obtained and at f/32, the image still is adequate for many purposes. The endpoint f/45 shows lowered contrast because of diffraction and a quite pronounced softening of the image. By contrast, other Micro-Nikkors rarely keep their image quality beyond f/11-f/16, and in general are terrible at f/22-f/32.
I think Nikon have made a prudent choice when they designed the 85 PC. It is clear that this kind of lens more often than not will be used well stopped down, and according to my tests, it still can deliver exceptional quality at aperture settings that would have ruined images from other lenses. The modest performance of the 85 PC wide or nearly wide open must be seen in this perspective.
I tried the 85 PC with several teleconverters to see whether the image quality would survive at acceptable levels. This it did with flying colours, using either the TC14B, TC14C or TC-200/201 converters. The TC-301 cannot be used because of its protruding neck that interferes with the rear elements of the 85PC. My test shots indicated that 85 PC is unusually versatile as far as teleconverters go and this certainly adds to its usefulness for field shooting.
|Taking an oblique view of the newly fallen autumn leaves is a breeze with the 85 mm f/2.8 PC Micro-Nikkor and its tilting capacity. Even up close, everything is in sharp focus at all apertures. Click the insert to view a 3 x 4 mm detail (shot at f/16).|
|© Bjørn Rørslett/NN 1999|
The 85 PC is a remarkable and amazing lens, that well deserves a total ranking of 5 (Excellent). I'm looking forward to enjoyous photo opportunities with my 85 PC and shall post more pictures taken with it when they become available.
Since the above review was written, I have used the 85 PC extensively both on my F5 and D1/ D1X, and continue to be amazed of the superb image quality attainable with it. Images are crisp and clear across the entire frame and colour rendition are amazing with rich, vibrant colours. Ghosting occasionally occurs but isn't a big problem in practice, and flare is minimised when the lens is stopped a couple of stops down. My only practical complaint is that there is a slight tendency to creep in the focusing ring when the lens is approaching the near limit and is pointing downwards. Other 85 PC lenses I have tried, however, had stiffer focusing action so this was less of an issue with them. OK, so if this little annoyance persists and develops further with my personal 85 PC, I probably have to add a locking screw to the focusing barrel. No big deal, really.
Later on, I had the lens serviced by Nikon's national repair facility here in Norway to give it a stiffer focusing action, and so far this remedy seems to solve the creeping issue. The final answer will be given when I start using the 85 PC next winter, because in the cold you cannot have too stiff focusing either. As always, a compromise has to be struck. (As events later turned out, the 85 PC did not become too stiff in its focusing action. However, the creeping issue still persists although reduced in magnitude).