John Riley reviews the Asahi Super-Multi-Coated Takumar 135mm f/3.5 lens on a 36mp Full-Frame Pentax K-1 DSLR.
Posted: 01/05/2018 - 14:44
Handling and Features
Performance
Verdict
Specification
Even as late as the early 1970s the classic lens set for amateur photographers would be the 35mm, 50mm and 135mm lenses. Very often the 135mm would be the first purchase after the camera body with its ubiquitous 50/55mm lens. Why 135mm? This goes even further back to the Leica, 135mm being the longest lens that can be accurately focused on a rangefinder camera. With longer lenses, the SLR is more accurate. There seems to be an almost unlimited supply of inexpensive 135mm lenses on the second-hand market, some at incredibly low prices. Let's have a closer look at one of the better-known lenses from Asahi Pentax and see how it stacks up on the full frame Pentax K-1 body.
Asahi Super-Multi-Coated Takumar 135mm f/3.5 Handling and Features
This Super-Multi-Coated version of the 135mm f/3.5 lens from Asahi Optical Co. Ltd. is a 42mm screw thread lens intended for use on the Pentax Spotmatic cameras. Optically it is the same as the Super Takumar Model II that preceded it. This newer version, made from 1971-1975, has the new SMC 7-layer coating, plus the mechanical meter coupling for the Spotmatic F body. This means that, with the right camera, metering can be measured at open aperture without having to stop the lens down to the working aperture. This is no longer supported so stop-down metering needs to be used with the K-1. We also need the Pentax Adapter K to enable the screw thread lens to be used on the bayonet fit camera body. The correct technique is to fit the adapter to the lens and then bayonet onto the body. Screw thread lenses can then be removed and fitted as the camera has in effect been converted temporarily into a screw thread body. As the adapter is flush with the mount there is no problem with infinity focus.
Users of modern lenses may be quite surprised at how slim these lenses are. All metal and glass, although at 340g it feels solid enough. It also looks extremely well made, with high-class engraving and super-smooth operation of the large focusing ring.
There is a 49mm filter thread and a dedicated screw-in lens hood that is used for this lens and also for the 150mm f/4. The hood is, of course, metal. The focusing is so gorgeously smooth that operating it is a tactile pleasure that needs to be experienced. A cut out reveals the focus scale, marked clearly in feet and metres. There is also a meaningful depth of field scale, plus an extra red line that indicates the infra-red focusing position. If using IR film the user would focus and then shift the focusing ring to the IR mark. Lenses were not corrected to focus IR light and visible light at the same point.
Focusing at open aperture, for best results Live View is the most effective method. The focusing screens on AF DSLRs do not have any of the traditional focusing aids such as microprism spots or split image rangefinder spots and so can be quite difficult to use for manual focusing, but a magnified Live View image does the trick. After focusing, the lens needs to be stopped down to the working aperture. Av and M modes will allow metering.
The aperture ring has half stop indents and is smooth in operation, running from f/3.5 to f/16 and then a full stop to f/22. Behind this is the Auto/Manual switch which selects open aperture and closed down aperture. This is very useful for DSLR metering as set to Auto the diaphragm opens to maximum aperture and focusing is easier. The beep of the K-1 focus confirmation is an added guide to getting the focus spot on. For this to work, the camera should be set to AF. When we are ready to shoot the image moving the lever to Manual will stop the lens down to whatever value we have selected. The alternative technique is to leave the switch on Manual and just use the aperture ring to open the lens up, then count down the steps to set whatever working aperture is desired. It should be noted that some A/M levers will only work when the lens is mounted on the camera, so one that is solidly fixed may not indicate a fault.
Optical construction is 4 elements in 4 groups, a classic configuration for a lens of this specification. Focusing is down to 1.5m or 5 feet, which is not really anywhere near as close as we have become used to. Nonetheless, it is much better than the 13 feet minimum focus of some 1950s SLR lenses.
In use, the 135mm could be considered a little too long for some photographers, but it does have good reach and on an APS-C crop sensor camera would have a “35mm format equivalent” field of view of a 200mm lens. On full frame, it is particularly useful for tight portraits, architecture, close sports and landscape.
Asahi Super-Multi-Coated Takumar 135mm f/3.5 Performance
Centrally, sharpness is good at f/3.5, becoming very good from f/5.6 through to f/22. The edges are good at f/3.5, very good from f/5.6 to f/11, good at f/16 but softening at f/22. This results overall in nice crisp images and it does mean that the lens is very usable on DSLRs.
Asahi Super-Multi-Coated Takumar 135mm f/3.5 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 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.
Central correction of CA is of a very high order, but the edges are rather less well corrected. This could be tackled in software, and to be fair many subjects will not be a problem anyway.
Asahi Super-Multi-Coated Takumar 135mm f/3.5 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 correction is very impressive, being a modest +0.09% pincushion.
The bokeh of the lens is a bit more disappointing. It does come from an era where bokeh was not a term used and the quality of the out of focus areas was not discussed in the same way that it is now. The result on digital is a rather “busy” appearance, but again this will depend on the subject matter as well.
The SMC coating was a revelation is 1971 but has constantly progressed and developed since then. This lens controls flare very well, perhaps not quite up to modern standards, but certainly, it is more than adequate. Flare is unlikely to be a problem, especially when the effective lens hood is used.
Asahi Super-Multi-Coated Takumar 135mm f/3.5 Sample Photos
Asahi Super-Multi-Coated Takumar 135mm f/3.5 Verdict
The sample used for review was found on eBay and purchased for £26 plus shipping. It's a superb lens at that price, fun to use and absolutely viable on a modern DSLR. Manual focus may not suit everyone, but the tactile feel of it is sublime. Well worth a try and this could easily become a firm favourite.
Asahi SMC Takumar 135mm f/3.5 Pros
- Inexpensive
- Very good sharpness
- Very low CA
- Very low distortion
- Ultra smooth handling
- Light and compact
Asahi SMC Takumar 135mm f/3.5 Cons
- Manual focus won't suit some
Specifications: Asahi Super-Multi-Coated Takumar 135mm f/3.5 |
||||
| General | ||||
| Focal Type | Telephoto | |||
| Lens Mounts | Pentax M42 | |||
| Availability | ||||
| Year announced | 1971 | |||
| Discontinued | Yes | |||
| Dimensions | ||||
| Weight | 340g | |||
| Construction | ||||
| Groups | 4 | |||
| Elements | 4 | |||
| Lens | ||||
| Stabilised | No | |||
| Filter Size | 49mm | |||
| Min Aperture | f/22 | |||
| Max Aperture | f/3.5 | |||
| Focal Length | 135mm | |||
| Focusing | ||||
| Focusing modes | Manual | |||
| Macro | No | |||
| Min Focus | 150cm | |||
Members photos with related tags: Takumar,135mm
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