Monster Adapter LA-KE1 Pentax K to Sony E Lens Adapter

Compared to Other Adapters

When Sony moved from A mount to E mount they created a problem for their users. The A mount lenses were incompatible with the E mount interface. Several adapters were created by Sony to handle A mount lenses: LA-EA1/2/3/4/5. The LA-EA3/4/5 series are the ones compatible with full frame. The LA-EA3 offers compatibility with A mount lenses that have internal focus motors. The LA-EA4 uses an SLT type transparent mirror and a PDAF focusing system built into the adapter to add screw drive compatibility. The LA-EA5 is the oddest of these as it is like the LA-EA3 - using the camera's own PDAF sensors and focus mechanisms including Eye-AF (just like the Monster LA-KE1) but the screw drive features of the LA-EA5 are only enabled for the A7RIV and A6600 cameras.  

In many ways we can conceptualize of the LA-KE1 as an LA-EA3 for K mount. Functionally the features are quite similar. The LA-EA3 however is a more traditional adapter in that it does not need a specific set of lenses, just a set of features. Any USD/SSM/SAM lens in theory can work, including third party lenses. Some lenses might behave badly but this case by case validation is typical of all third party lenses on Sony. The Monster Adapter, however, requires additional data for the Sony bodies that the Pentax lenses do not natively supply. This requires a profile for each supported lens to be built into the Monster Adapter and thus a very specific list of lenses is provided with each version of the firmware. As shown before, the list is extensive, but not complete, particularly regarding third-party lenses.

Autofocus Adapters

The Sigma MC-11 and similar Comlite products offer Canon-EF lens compatibility. Like the LA-EA3, this relies on the camera's own focus mechanisms. Unlike A mount or any other mount the EF lenses have always supported autofocus using internal motors. Also unlike Nikon F or Pentax K, electronic aperture has been supported by EF from day 1. This makes support a little simpler. Even then, third-party lenses support can be a bit hit or miss. The best compatibility is from the Sigma MC-11 with Sigma or Canon lenses. The MC-11 offers a similar value proposition for those moving from Canon EF to Sony.  

The Techart/Fotodiox Autofocus Adapter is a final option. This device provides a function similar to the Pentax F 1.7x without the 1.7x teleconverter feature. The device fits to a Sony E mount camera (with limitations on which bodies are supported) and moves the entire mount in and out. Since it is designed for M mount Leica lenses with shorter registration distances than Pentax, an adapter from K-mount to M-mount allows the use of this device on E mount cameras with K mount lenses. This system allows 4.5mm of focus shift, which is not always sufficient to fully cover the focusing range of a lens, requiring some prefocus like the F 1.7X TC. The adapter does not supply EXIF data, has no aperture control (so only lenses with aperture rings are fully usable), and has had reported issues with the mount sagging over time when using heavier lenses. This adapter is best limited to lightweight prime lenses. This adapter costs as much as the Monster LA-KE1. It is more likely to work with third-party lenses.

Adapter Price Mount Features
Monster LA-KE1 $439 K mount to E mount Autofocus, EXIF, Aperture Control, Image stabilization
Techart Pro Leica M to Sony E $379+$70 for adapter Anything that can be adapted to M mount Autofocus (with prefocus), requires aperture ring
Sigma MC-11 $249 EF Mount to E mount (no K-mount support) Autofocus, EXIF, Aperture Control

Manual Focus Adapters

There is no lack of purely manual focus adapters to attach K-mount lenses to Sony cameras. They are all mostly the same: a metal adapter coupling the lens to the camera, correcting for the register distance. The best ones offer aperture control via a ring on the adapter, such as the adapter from Novoflex. This is purely mechanical, moving the lens's aperture lever. Of course this requires that the lens does have such a lever, which therefore excludes KAF4 lenses. There are no numbers on the adapters, so the aperture ring moves in a clickless manner. The actual aperture must be guessed by the user, but has the advantage of offering a direct DOF preview on-screen, as well as real-time metering.

These adapters are also manual focus. As such, they can be used with almost every Pentax lens ever made, with exceptions such as the DA 18-50mm and DA* 16-50mm PLM which use focus by wire instead of mechanical focus.

Some of the most interesting manual adapters available are listed below.

Brand Model Weightd Aperture Control
Novaflex NEX/PENT 100g Infinitely adjustable Aperture Ring
K&F Concept PK/DA-E 121g Infinitely adjustable Aperture Ring
Haoge DA-NEX 99g Infinitely adjustable Aperture Ring, w/two fixed steps

In general these adapters are all fairly well made. The Novaflex is the nicest, and most expensive, of the three. It offers a very smooth feel and function. The K&F has pleasing aesthetics; the aperture control ring echoes the styling of the Novaflex (silver rather than blue) and offers a solid feel. Lastly, the Haoge adapter has a styling that might seem a bit garish.  The feel of the aperture adjustment ring is adequate but not as polished and clean to operate as the K&F or Novaflex. The ring has two positive locking positions - open and closed.  However even with these two positions it is possible to stop in between at infinitely adjustable positions. The throw is fairly short and the two click stops will make it easier to overshoot your intended position at times. The overall build of this adapter is unlike the other two in that it has no ridged grooves for light reflection abetment inside the shaft, only flat black paint.

Conclusion

There are many fully manual adapters available on the market, that come with the limitations expected with the lack of any electronic coupling.

There are several AF E-mount adapters in existence, but only one supporting K-mount lenses. This TechArt adapter is in fact another manual adapter, but able to move the whole lens forward and backwards, achieving autofocus without involving the lens.

The Monster Adapter LA-KE1 is thus completely unique on the market.


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