The Hollywood - John Riley puts the fast K series Pentax 28mm f/2 lens to test, providing sample photos, MTF & CA charts along with his verdict of this lens with a big reputation.
Posted: 27/08/2024 - 14:24
Handling and Features
Performance
Verdict
Specification
We continue our look at the Pentax K lens range, introduced along with the New K bayonet cameras, the KM, KX and K2. As well as the K bayonet itself being created out of the collaboration with Zeiss, so too were some of the new lens designs, such as the 15mm f/3.5 and the 28mm f/2. The SMC Pentax 28mm f/2 has something of a reputation, reputedly based upon the design of the Zeiss Distagon 28mm f/2 T* lens, known generally as the Hollywood because of its fine rendition and superb bokeh. The Pentax lens uses the same basic formula and is actually preferred by some photographers. Having the chance to test a fine sample of the lens is intriguing, as of course its qualities on digital could be very different to its qualities on film. So let's find out, using the 36MP Pentax K-1 and an early sample of the SMC Pentax 28mm f/2 lens. Will it retain the Hollywood magic? Read on...
SMC Pentax 28mm f/2 Handling and Features
There are several versions of the Pentax 28mm f/2 lens, some having very different optical designs. The sample we have here for review, kindly loaned to us by PU member womble, is the original Zeiss design of 9 elements in 8 groups, manufactured from 1976-1981. Refining that still further, the designations on the front of the lens indicate that this is one of the earliest versions of the lens. Although at the time it must have seemed quite bulky for a 28mm, compared to modern designs it really is quite compact, weighing in at 424g (as measured) without caps, although the literature suggests 423g, and with dimensions of just 62.5mm x 69mm.
There is a dedicated lens hood, PH-S52, but this was not provided with the lens. In its day it would have been an optional extra, supplied in its own very fine leather case. Filter size is 52mm, the norm for the original K series lenses.
The wide focusing ring has an excellent grip. In this instance the action of the focusing is slightly firmer than usual but it exceptionally smooth in its action, as expected. There is the usual cut out for the distance scale, which is clearly engraved with distances in feet (blue) and yellow (metres). There is an infra-red correction mark at the f/4 position on the depth of field scale. The focusing index is marked in red, as is the 10 feet/ 3 metres position on the focusing scale. This offers a marker for a snapshot setting. If, for example, the lens is set at f/8 then at the marker the hyperfocal distance gives a depth of field from infinity to around 4 feet, ideal for a quick shot or perhaps street photography. This is a common feature of Pentax wide angle lenses of the era.
Closest focus is just under 0.30m, or 1 foot, giving a maximum magnification of 0.11x. This is on a par with other Pentax 28mm lenses of the 1970s and 1980s.
There is a white plastic bubble on the lens that can be used to align with the lens release button, making changing lenses easier by touch in dim lighting.
Optical construction is 9 elements in 8 groups, with the diaphragm consisting of six blades. The shape of these blades can be clearly seen in out of focus highlights in images, very different from the rounded apertures that are now considered desirable. Neither better nor worse, but just different and subject to the vagaries of current tastes.
The aperture ring is the usual high qauality, with firm but smooth click stops at half stop intervals, the exception being full stop intervals between f/2 and f/2.8 and f/16 and f/22. It is worth noting that generally K lenses stop down further than the previous screw thread lenses did, so f/22 becomes available on wide angles. Diffraction does take its toll on sharpness at these small apertures, but having the choice is useful for situations where depth of field is the most important factor.
The basic K mount is beautifully manufactured in stainless steel and the tolerances are so good that even this old lens still mounts into place smoothly on current DSLRs. There are good reasons for changing to a bayonet mount. The lens throat is increased in diameter from 42mm to 45mm, thus enabling more ambitious lens designs, especially fast primes and new wider ranging zooms. There is also the obvious convenience of faster lens changing. In typical Pentax form, an adapter allows the use of older screw mount lenses, following the tradition of ensuring our old lenses can be used on our new cameras.
Being a manual focus lens with no electronic communication with the camera, there are some handling pointers to think about. When the camera is switched on it will ask what the focal length is, for the purposes of setting the shake reduction system correctly. Then we need to focus the lens, and this may be a lost art for many that needs relearning, but with no visual aids in the viewfinder to help. No microprisms to shimmer when out of focus, no split image rangefinder to align to find perfect focus, just the eye judging the point of sharpness. Unfortunately most eyes are quite poor at this and the amount of variation when finding that point of focus is significant, especially with a telephoto lens where depth of field is reduced. The answer is Live View, and using LV with magnification reveals that point of focus easily and also shows up how dismal the ability of the human eye can be. This has always been known and in the past various magazines have demonstrated this in tests. At longer distances and smaller apertures we get away with it more easily, but close up with wide apertures or where precision is necessary then the use of LV with magnification is the way forward.
Even with a wide angle lens shake reduction can be useful. On a tripod this should be switched off. With the use of the self timer even the vibration caused by releasing the shutter is avoided by the mirror being raised before the shutter is released.
As there is no communication with the camera, exposure is via stop down. Focus the lens, set the aperture on the lens, press the green button and the lens will briefly stop down, exposure will be measured and the camera will set the shutter speed. The lens opens up again. Them when the shutter is released the lens will stop down to the apprpriate aperture. With practice, the process is simple and quick.
We can also use an APS-C crop sensor DSLR of course, in which case the “35mm equivalent” field of view for a 28mm lens will be around 42mm. This is effectively a "wide standard" on APS-C format, which may suit some photographers very well. One of the joys of using the full frame K-1 is that our wide angle lenses are fully usable as intended.
SMC PENTAX 28mm f/2 Sample Photos
It is interesting how tastes develop over the years, and at one time a 28mm lens would have been considered very wide, 35mm being the norm. Now this is much less the case, and even the 24mm is only just an ultra-wide. Also, 28mm lenses would have been f/3.5 or f/2.8 and this f/2 is therefore very fast indeed. The price would have been something like three times the price of an f2.8 lens, so the 28mm f/2 was certainly something special that not everyone could afford.
The f/2 maximum aperture does have some practical benefits. It means depth of field can be reduced, so it is possible to achieve some out of focus backgrounds. It is also easier to focus, as the image snaps in and out slightly more clearly. This is true when using the optical viewfinder, but the best focus is achieved by using Live View and magnification, as mentioned above.
The lens has a fine pedigree and a high price tag to go with it, so let's see if its reputation is deserved and whether or not it remains a classy performer when used with digital cameras.
SMC Pentax 28mm f/2 Performance
Central sharpness is very good from f/2 to f/4, excellent from f/5.6 to f/11, very good at f/16 and good at f/22. The edges are just fair from f/2 to f/4, good at f/5.6, very good from f/8 to f/16 and fair at f/22.
SMC PENTAX 28mm f/2 MTF Charts
How to read our MTF charts
The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges.
The scale on the left side is an indication of actual image resolution and sharpness as LW/PH and is described in detail above. The taller the column, the better the lens performance.
For this review, the lens was tested on a Pentax K-1 using Imatest.
Film era wide angle lenses are not telecentric in design, that is the light rays do not exit the lens parallel to each other, but strike the outer areas of the image at oblique angles. This is fine with the flat film surface, but not so good with the pitted structure of a digital sensor. This clearly is having an effect here, with reduced edge sharpness at wider apertures. This is not so noticeable at longer distances rather than the relatively close distances of test targets. There is also an effect on Chromatic Aberration and although central correction is commendable, the edges do show quite a bit of CA. Most subjects do not show this up particularly, but challenging situations such as branches against bright sky certainly do reveal some colour fringing. Software correction can be used if necessary.
SMC PENTAX 28mm f/2 Chromatic Aberration Charts
How to read our CA charts
Chromatic aberration (CA) is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.
Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.
For this review, the lens was tested on a Pentax K-1 using Imatest.
Distortion measures -1.51% barrel, which is reasonable for a fast wide angle. Further correction in software can always be used if necessary.
Bokeh is the smoothness of the out of focus areas in an image, and a major consideration considering the Hollywood reputation of the lens. Is this borne out on digital? Well, there is no doubt the results are good, in fact very good, with smooth rendition and a very pleasing overall "look". However, this could also be said of many other Pentax lenses. At the same time, the images produced do show some very attractive qualities.
SMC PENTAX 28mm f/2 Aperture Range
The SMC coating has improved over the years, but is very satisfactory and in the 1970s was ahead of many of its competitors. The flare resistance is excellent, even without a lens hood, and although slight artefacts can be induced, we have to work very hard at making it so.
Vignetting is noticeable at open aperture, but soon reduces to very acceptable levels for a fast wide angle.
| Aperture | Vignetting |
| f/2 | -2.1 |
| f/2.8 | -1.6 |
| f/4 | -1.3 |
| f/5.6 | -1.3 |
| f/8 | -1.3 |
| f/11 | -1.3 |
| f/16 | -1.3 |
| f/22 | -1.2 |
Value for Money
There will be competition for this lens, from collectors and users. It is inevitable that the price will therefore be high, and it generally is. The value becomes whatever the user is prepared to pay, and if we just want a 28mm lens for use this will not be the most cost effective route. It was not an inexpensive lens when new, and continues to not be inexpensive currently.
Although not really high in the VFM stakes, it could still be desirable as a lens and those who can afford the cost won't hesitate anyway.
SMC Pentax 28mm f/2 Verdict
This is a tricky one. A lens with a fine reputation, and it is clear to see why as its rendition of images is impressive. However, it is not clear that it is significantly more impressive that many other Pentax lenses that are available at much lower price levels. In terms of hard technical data there are many defects in terms of edge sharpness, CA and vignetting, along with plus points in central sharpness, central CA, bokeh and resistance to flare. In terms of aesthetic considerations of the images produced, it is that very mix of properties that produces a very pleasing rendition indeed. Like descriptions of bokeh, some things defy hard measurements. We produce aesthetically pleasing images, not reproductions of test charts, even if the one does inform the other to some degree.
Overall, the lens produces some lovely results, and Hollywood or not it is worthy on digital of being Highly Recommended.
Further reading - Pentax K Series - The Original K Mount
SMC Pentax 28mm f/2 Pros
- Impressive central sharpness
- Well made
- Very pleasing imaging characteristics
- Smooth bokeh
- Excellent flare resistance
- Low central CA
- Reasonable distortion
- Lovely tactile handling
SMC Pentax 28mm f/2 Cons
- Softer edges
- Edge CA
- Stop down metering
- Manual focus
- Expensive
Specifications: SMC PENTAX 28mm f/2 |
||||
| General | ||||
| Focal Type | Wide | |||
| Availability | ||||
| Year announced | 1976 | |||
| Discontinued | Yes | |||
| Dimensions | ||||
| Diameter | 62.5mm | |||
| Height | 69mm | |||
| Weight | 423g | |||
| Construction | ||||
| Weather-sealed | No | |||
| Groups | 8 | |||
| Elements | 9 | |||
| Blades | 6 | |||
| Lens | ||||
| Maximum magnification | 0.11x | |||
| Internal focusing | No | |||
| 35mm equivalent | 35mm | |||
| Stabilised | No | |||
| Filter Size | 52mm | |||
| Min Aperture | f/22 | |||
| Max Aperture | f/2 | |||
| Focal Length | 28mm | |||
| Focusing | ||||
| Min Focus | 30cm | |||
Which would you say are it competitors within the Pentax lens lineups?
If we ignore focal length for a moment, for me lenses such as the SMC Pentax-M 100mm f/2.8, SMC Pentax-FA 43mm f/1.9 Limited, SMC Pentax-DA 70mm f/2.4 Limited all have a certain "quality" that hits the spot. These are not necessarily the highest rsolution, as for example the 70mm is in terms of sharpness not quite as good at the 77mm f/1.8, but I prefer it.
There's no simple answer to this very good question, as the character of a lens also involves some subjective assessment. What sort of final image do we like?
Looking at wide angle lenses, then there are some zooms that have attractive rendering, such as the 20-35mm f/4 and the 24-90mm. There is a lot of competition that gives the Hollywood a good run for its money.
Which would you say are it competitors within the Pentax lens lineups?
... SMC Pentax-M 100mm f/2.8, SMC Pentax-FA 43mm f/1.9 Limited, SMC Pentax-DA 70mm f/2.4 Limited all have a certain "quality" that hits the spot...2 These are not necessarily the highest rsolution, as for example the 70mm is in terms of sharpness not quite as good at the 77mm
The M100 is one of my favourite lenses. For some reason or other, I've never really got on with the 43 Ltd, but the 31mm Ltd is almost glued to my K-3iii. I use the K30/2.8 more than the "Hollywood" --- especially on film --- mainly due to size. The K30 also has a lovely rendering.
It is an illusion that photos are made with the camera… they are made with the eye, heart and head. Henri Cartier-Bresson
Lots of film bodies, a couple of digital ones, too many lenses (mainly older glass) and a Horseman LE 5x4.
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7625 posts
16 years
Hertfordshire,
mostly.
It is an illusion that photos are made with the camera… they are made with the eye, heart and head. Henri Cartier-Bresson
Lots of film bodies, a couple of digital ones, too many lenses (mainly older glass) and a Horseman LE 5x4.