Gary Wolstenholme reviews the Pentax HD PENTAX DA AF 1.4X AW Rear Converter for Pentax Digital SLRs.
Posted: 01/07/2014 - 10:15
Handling and Features
Performance
Verdict
Specification
This 1.4x tele-converter fits between a lens and your Pentax camera, increasing the focal length of the lens by 40% and reducing the maximum aperture by one stop. This particular converter sports Pentax's HD lens coatings and is designed to be water and dust resistant, when used with a Pentax lens offering the same levels of sealing. In this review, we'll take a look at how it performs when used with a Pentax 50-135mm f/2.8 lens.
HD PENTAX-DA AF 1.4X AW Rear Converter Handling and Features
Weighing only 126 grams, this 1.4x converter is an ideal way of adding extra focal length, without adding much extra weight to carry around. The Build quality of the converter is very good, with tough plastics and metal used in combination for much of the converter's construction.
There are few controls on the converter, with only a release latch for locking the converter to the camera sticking out of the side. A red rubber gasket on the rear of the converter provides a seal against the camera body to help prevent the ingress of dust and moisture. The seal on a water resistant Pentax lens then presses against the flat front of the converter.
The full complement of electronic contacts to support even Pentax's old Power Zoom lenses are supplied, and even the mechanical focus screw is carried through the converter. The lens diaphragm is operated by a lever inside the converter. The converter is easy to fit, and the close focusing distance of the mounted lens remains unaffected, allowing more of the frame to be filled with less of your subject.
When used with the 50-135mm f/2.8 lens, focus speeds seem largely unaffected in good light conditions. As light levels drop, the converter can cause the lens to focus more slowly, or even hunt a little for lock, but only when conditions are pretty murky.
HD PENTAX-DA AF 1.4X AW Rear Converter Performance
To test the converter, we checked the sharpness with the 50-135mm lens at either end of the zoom range. Overall, sharpness is reduced compared to using the lens on its own.
As you might expect, there is a slight reduction in the sharpness delivered by the 50-135mm lens, when the 1.4x converter is attached, especially at maximum aperture. Even so, the lens and converter combination is still capable of delivering outstanding sharpness levels when stopped down to f/5.6 and beyond.
HD PENTAX-DA AF 1.4X AW rear converter
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-5 IIs using Imatest.
Levels of chromatic aberrations are increased to levels that may be noticeable along high contrast edges. At both ends of the zoom range, fringing exceed one pixel width at maximum aperture, towards the edges of the frame.
HD PENTAX-DA AF 1.4X AW rear converter
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-5 IIs using Imatest.
Falloff of illumination towards the corners of the frame is vastly reduced with the converter in place, to the point where illumination is visually uniform across the frame. Without the converter, the corners of the frame are 0.8 stops darker than the image centre at 50mm and at 135mm the corners are 1.2 stops darker.
Distortion is also reduced, with only 0.32% barrel distortion at the wide end of the zoom and 0.8% pincushion distortion present at the telephoto end. Without the converter, Imatest detected 0.7% barrel distortion at 50mm, which is replaced by 1.68% pincushion distortion at 135mm.
With the converter in place, contrast is pretty much the same as without, even when shooting into the light at maximum aperture.
HD PENTAX-DA AF 1.4X AW rear converter Sample Photos
Value For Money
Being priced at around £380, this converter offers a cost-effective way of gaining extra telephoto reach with existing lenses.
Although this may seem like excellent value, compared to forking out for a longer telephoto lens, Kenko produce a Teleplus 1.4x converter, which costs only £109. Although this converter will offer the same gain in telephoto reach, it doesn't offer any protection against dust, or the elements.
HD PENTAX-DA AF 1.4X AW Rear Converter Verdict
In the past, tele-converters gained a reputation for poor image quality, forcing too many compromises from your existing lenses. Pentax has proved with this converter that you need not compromise on image quality with a tele-converter, nor on weather sealing, or handling. This converter will be well worthy of consideration by those who already own compatible lenses.
Pros
- Only a very small reduction in sharpness with converter
- Excellent build quality
- Lightweight
- Compact
- Reduced falloff and distortion with converter
Cons
- CA levels are raised by the converter
- Less expensive alternatives are available
Specifications: HD PENTAX-DA AF 1.4X AW rear converter |
||||
| Availability | ||||
| Discontinued | No | |||
| Year announced | 2014 | |||
| Dimensions | ||||
| Height | 20mm | |||
| Lens | ||||
| Effective Magnification | 1.4x | |||
| Fitting | K | |||
Members photos with related tags: Pentax,Converter,1.4X
Although this may seem like excellent value, compared to forking out for a longer telephoto lens, Kenko produce a Teleplus 1.4x converter, which costs only £109. Although this converter will offer the same gain in telephoto reach, it doesn't offer any protection against dust, or the elements.
Slightly academic considering the present Kenko does not work with SDM lenses such as the Pentax 50-135mm f2.8 you are using here to review the Pentax teleconverter.
My converter bayonet part with all the contacts looks exactly the same as does the Pentax converter.
It has the 7 contact points, the 2 contacts for the power zoom lenses and the screw drive focus.
Regards, Horst
I would think that by far the vast majority of people contemplating getting this converter are those who wish to use it with the DA* 300mm.
Not to test it with that lens and not to do comparisons between images cropped from the 300mm and images straight from the 300mm +1.4 TC is a glaring ommission.
Hope you put it right, otherwise the review is of little value to that majority
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My thoughts exactly while I was reading the review.
The visible CA and sharpness is identical as is the operational performance on several lenses used on test, even displaying the same focussing anomalies which are quite minor given it is a supplementary component between the body and lens.
The configuration is also identical and the only physical difference results from the WR sealing
Whilst not a fan of TC's I have found the Tamron acceptable in some circumstance and after the test I returned my new Pentax TC.
I have always carried the Tamron in my bag (FROM FILM DAYS) through some very hostile environments in terms of extreme conditions, having lived and worked in the tropics and also numerous extremely cold regions; on the very rare occasions I have had a real need or advantage to use it it has not been hampered by the lack of WR sealing.
Yes! - the Tamron has been with me since 35mm days, it has performed faultlessly in terms of "what it said on the tin" when it was bought and still looks like new, and a further " yes" to the fact it couples and functions perfectly on the K3 and K5 IIs.
In fact the Tamron 1.4 x TC construction and configuration is so physically similar to the " new Pentax" you could be forgiven for thinking the latter comes from the "same stable" so to speak.
The hype surrounding the new Pentax 1.4 TC is a little misplaced for me and anyone in possession of a Tamron 1.4 TC would do well to hang on to it as the quite punitive cost of the new Pentax version provides little other than the " WR" which experience has shown under very adverse conditions, coupled with the infrequent need for it's deployment make it a little tough to justify in terms of purchase / expenditure.
Finally, if one spends £1000 on a DA* lens such as the 60-250, would one really want to " take the edge off the image" - I don't ???
Got it “new”. Excellent built quality, indeed. But, what a deceiving AF performance (curiously no mention of AF in the review verdict). I use it on Pentax 300 DA* with K-3. Slight loss of detail, but sharpness seems OK. Slightly higher colour noise in some circumstances. AF with converter on is sometimes noisier, always pretty slower and unreliable. IMHO, birders and sport photographers better to avoid.
Pentax HD DA AF-CONVERTER 1,4x AW
Got it “new”. Excellent built quality, indeed. But, what a deceiving AF performance (curiously no mention of AF in the review verdict). I use it on Pentax 300 DA* with K-3. Slight loss of detail, but sharpness seems OK. Slightly higher colour noise in some circumstances. AF with converter on is sometimes noisier, always pretty slower and unreliable. IMHO, birders and sport photographers better to avoid.
After all, to be honest I’m not sure at all that my 300 DA* is not at the very origin of experimented AF issues .. sorry about that.
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4248 posts
14 years
Blyth,
Northumberland
Not to test it with that lens and not to do comparisons between images cropped from the 300mm and images straight from the 300mm +1.4 TC is a glaring ommission.
Hope you put it right, otherwise the review is of little value to that majority
PPG
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