- Very good central sharpness
- Low central CA
- Moderate distortion
- Light and compact
- Flare resistant
- Lovely smooth operation
- Low cost
- Manual focus won’t suit some
- Lower edge sharpness
- Edge fringing
- Vignetting throughout aperture range
Before the advent of the AF lens the typical amateur lens line-up would be 35mm-50mm-135mm, which eventually evolved to 28mm-50mm-135mm as our idea of what constituted a wide angle developed. Apart from the marque offerings there were a vast number of third party 28mm lenses, usually f/2.8, some good, some less so. The Chinon name in the UK was fairly synonymous with Dixons Photographic, featuring cameras and lenses sourced from many Japanese factories. Here we have a fairly late and pristine multi coated K mount lens, coupled with a Pentax K-1 36MP full frame body. Let’s see what it can do.
Handling and Features
In common with similar designs of the era, this is a very compact lens, weighing in at a modest 202g without caps. No lens hood was supplied as standard, so here an Olympus 28mm hood from the same era was used. The filter thread is 49mm, so any filters used should be relatively low cost.
Whatever we have gained with modern lenses, it becomes immediately obvious that one thing we have lost is the delightful, silky smooth feel of a finely made manual focus lens. This Chinon may have been an inexpensive option compared to the marque lenses, but it is every bit as gorgeous as say a Pentax M series optic. It is beautifully tactile in operation. The same fine quality experience is also felt with the aperture ring, which is just perfect in its balance between smoothness and enough firmness to prevent it being sloppy in action.
The distance scale is clearly marked in feet and metres and a useful and meaningful depth of field scale is also provided. Apart from that, there are no electronic contacts and no other features on the lens.
It is worth mentioning that the “auto” in the lens name refers to an automatic diaphragm, where the lens close down to the aperture selected when the shutter is released and then opens up again instantly for focusing. At a time when many lenses were preset and had to be used manually the auto diaphragm was a feature to be mentioned. Now we take it for granted.
Focusing is quite positive visually, aided by the Pentax K-1 giving a confirmation beep if the camera is set to AF. Although wide angle lenses will always be more difficult to focus manually, in this case it works relatively well. It is even more accurate if Live View is used with magnification. There is no electronic information being exchanged between camera and lens the exposure system has to be used in manual stop down mode. In the case of Pentax cameras, the mode dial is set to M, the green button pressed, the camera briefly stops down, takes an exposure measurement and sets the shutter speed to match the aperture in use. Then the exposure can be made and the lens will stop down correctly.
The lens focuses down to just under 1 foot, or about 0.3m, which is what we would expect.
General handling is trouble free, the lens works well and the only real limitation is that stop down metering does slow down the picture taking process. Some may argue that this can be a good thing and can improve our attention to the details in our images.
Centrally, sharpness is very good from open aperture through to f/11. It is still good at f/16, only falling off into softness at f/22.
The edge sharpness is not so good using a test chart, being soft at f/2.8, fair between f/4 and f/5.6, good at f/8 and just fair between f/11 and f/22. This is not as bad as it sounds though, as at more normal shooting distances the results improve and visually the shots look very reasonable.
Chinon 28mm f/2.8 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.
CA (Chromatic Aberration) is very well controlled centrally, but at the edges things do go a little awry. Quite high levels of CA are noticeable, although to be fair not on all subject matter. Reduction of fringing in software could well be needed in many situations.
Chinon 28mm f/2.8 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 -1.72% barrel, a figure that is unlikely to be a problem in many situations, but if it is then software solutions may be the answer.
Bokeh is very satisfactory and gives attractive out of focus areas. There is vignetting of some -2.4 stops at f/2.8, reducing to -1.3 stops at f/4 and never really clearing after that but remaining at the same level. The compact design of the lens will be a contributory factor in this. However, a gentle darkening of the corners can often be a desirable thing. At one time it was routine to darken the corners of an image in the darkroom as it concentrates our eyes on the centre of the frame where the main subject is often placed.
Flare control is quite impressive. Severe backlight will create some artefacts, but the contrast level and colour remain good even under arduous conditions.
CA Test | 1/160 sec | 28.0 mm | ISO 100
Industrial Wasteland | 1/15 sec | 28.0 mm | ISO 100
Portrait 1 | 1/125 sec | 28.0 mm | ISO 200
Portrait 2 | 1/80 sec | 28.0 mm | ISO 200
Winding House | 1/50 sec | 28.0 mm | ISO 100
Chinon 28mm f/2.8 Aperture range
Bokeh At f/2.8 | 1/2000 sec | 28.0 mm | ISO 100
Bokeh At f/8 | 1/250 sec | 28.0 mm | ISO 100
Bokeh At f/16 | 1/40 sec | 28.0 mm | ISO 100
Bokeh At f/22 | 1/25 sec | 28.0 mm | ISO 100
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There is really very little to lose with a lens like this. Probably costing £10/$13 to £20/$26, a good example can produce very pleasing images and a good amount of fun can be had along the way. There are so many manual focus lenses out there and many of them, like this Chinon, are still capable of delivering very satisfactory results.