Pentax-DA 1.4x AW AF Rear Converter

Conclusion

The HD Pentax-DA 1.4x AW AF WR Rear Converter was long in coming, but it turns out that it was worth the wait. It provides for full exposure automation with modern lenses, and it supports both types of autofocus: screw drive driven by the motor on the camera, and SDM/DC, where the autofocus motor is placed in the lens.  It can also be used with legacy lenses and legacy cameras with certain limitations in functionality.

The rear converter is weather resistant and image quality only degrades marginally with this converter, while continuing to be better than what you'd get from an up-sampled image.  The converter adds no visible distortion or vignetting to the image but faithfully retains the characteristics of the lens albeit magnified by 1.4x. This means that lens flaws get magnified: and as an example bokeh when using the converter will come out slightly harsher than without, and purple/green fringing may be more pronounced.

This teleconverter is compatible with nearly the entire current Pentax lens lineup, and also with most legacy lenses.  There is a handful of modern lenses with which the converter is not compatible, but fortunately, most of these lenses are wide-angles that wouldn't normally be used with a teleconverter.  However, we still recommend that you check the specifications for compatibility before investing in the converter or a new lens.

We mounted the converter on a film body and did not notice any particular vignetting in the viewfinder with lenses 20mm or longer. This is not to say that the converter will be usable in practice with a full frame DSLR should Pentax release one, since firmware could prevent its use.

Who Is It For?

If you own a quality telephoto lens like the SMC Pentax-DA* 200mm or 300mm or a fast telephoto zoom and need more reach, then the HD Pentax-DA 1.4x Rear Converter is a viable option. It is a cost-effective way of adding that extra reach compared to buying another lens, and as a bonus, it does not take much space in your camera bag!  It can also be used with manual and third-party telephoto lenses for extra reach.

The teleconverter can also come in handy with shorter lenses. Say you're doing portraits with an FA 50mm or a DA* 55mm F1.4 lens and need to get closer. Use the rear converter and you now effectively have a 70mm F2.4 or a 77mm F2.4 lens, respectively. F2.4 still provides that narrow depth of field which is often desired for portraits (as explained earlier in the review in order to get the expected F2 from an F1.4 lens with converter you must use a non-autofocus lens).

The rear converter is also an option if you need more magnification for close-up photography. As an example it will provide 1.4x life-size magnification with a macro lens like the smc Pentax-D FA 100mm Macro WR which by itself would only go to 1x magnification.

We would not recommend using the 1.4x Rear Converter with wide lenses or with consumer zooms like the SMC Pentax-DA 50-200 F4-5.6 or 55-300mm F4-5.8 lens due to autofocus limitations. Viewfinder (phase detect) autofocus works best with lenses F4 or faster (live view must be used for reliable AF with slower lenses), and the converter amplifies lens flaws so it is preferable to use it in connection with top shelf lenses only.

Pros

• Excellent build quality
• Compact and light
• Excellent image quality, better than up-sampling
• Supports autofocus (SDM and screw drive) with little or no performance degradation
• Correct focal length (1.4x value set on lens) communicated to camera so shake reduction works optimally
• Weather sealed
• Compatible with almost every Pentax lens
• Works with all Pentax DSLRs, with only slight limitations on older cameras

Cons

• View finder autofocus (phase detect) is unreliable with lenses slower than F4 (live view should be used instead)
• Incorrect aperture in EXIF with A-series lenses
• Focal length not multplied on older DSLRs
• Magnifies optical lens flaws
• Relatively expensive

The Bottom Line

This rear converter is up there with the best in terms of optical quality. We can wholeheartedly recommend it in connection with quality lenses F4 or faster. The image quality with the converter beats upsampling a photo taken without it, so it's a no-brainer when you need that extra reach.

With F4 or faster lenses, autofocus works equally well with the converter as without it on modern Pentax DSLRs. Naturally, in low light the loss of one stop of light induced by the converter will affect autofocus speed.

Rating

The most difficult item to rate is value. The Rear Converter has a relatively high list price of $599 in the US, but can still be a bargain over buying an extra premium telephoto lens.  Furthermore, this is the only Pentax teleconverter with weather sealing, and the only teleconverter currently in production with both SDM and screwdrive autofocus support.

Rather than assigning too much weight to our value rating you should make your own judgment based on how often you need the extra reach or magnification that the rear converter provides held up against the type (size) and quality of images you want.

Get Yours Today

Click here to order the Pentax-DA 1.4 teleconverter at B&H Photo.  By doing so, you will help support future reviews and you'll be entitled to a free account upgrade on the forum.