Introduction to E-mount adapters
March 13, 2011 - Sony caused quite a stir in the compact interchangeable lens camera category by releasing the two smallest APS-C cameras yet: the NEX-3 and NEX-5. Being a totally new sytem with a new lens mount dubbed "E-mount", the choice of lenses at introduction was limited to two. But because of the short flange distance, the E-mount is perfectly suited for adapting to pretty much every other lens mount, albeit without automatic aperture control, autofocus, lens EXIF information, or image stabilization for lenses other than A-mount. Adapters for Nikon, Canon, M42, Leica, Minolta MC and MD, even passive A-mount adapters, and many more, are all up or a few tenners on E-bay.
In order to shoot pictures with passive adapters, you need to "enable" the setting "Release w/o lens" in the "Setup" menu.
Sony LA-EA1 Alpha NEX A-mount lens adapter
The Sony E-mount is electrically compatible with the A-mount for SLRs. Together with the NEX cameras, Sony released an active E-to-A mount adapter (part no. LA-EA1, €165) with which you can use A-mount optics on the NEXes. It increases the mount flange distance to that of an Alpha SLR and it has an actuator for the aperture lever to allow fully automatic exposure with every single A-mount lens. Unfortunately, Sony didn't -or was unable to- include a focus motor into the adapter, so autofocus is nothing but an electronic pass-through and will only work with lenses with a built-in focus motor: Sony SSM and SAM type lenses. Note however, that autofocusing this way is much slower than with an E-mount lens. For the autofocus to work, you'll also need to install the latest firmwares onto both your NEX camera and the adapter. The LA-EA1 has a detachable tripod mount, increasing stability of the camera over the camera's own tripod mount.
Autofocus is NOT and will NEVER be available for screw drive A-mount lenses.
An interesting fact to note is the NEX will use apertures larger than f/2 for auto-exposure. No A-mount SLR does this, to my personal chagrin.
Autofocus with third party A-mount lenses
I own 3 Sigma A-mount lenses with a focus motor (Sigma's HSM system). I briefly tested AF on these three lenses and was sorely disappointed. I wasn't expecting fast single pass AF, I was ready to see the NEX make a full sweep, scanning the scene, and then return to the focus position where contrast is at its highest. But none of that all. With the 50 mm f/1.4 HSM, the lens I was hoping to use extensively on the NEX, the camera simply does not lock focus. Ever. I tried dozens of times on very contrasty subjects, but the NEX keeps sweeping and juddering the focus scale, shooting past the in-focus position several times, and simply gives up after a good 5 seconds. The exact same goes for the 24-70 mm f/2.8 EX HSM and the 70-200 mm f/2.8 II EX HSM. Very, very disappointing. AF is supposedly a PID loop algorithm. How can it fail so miserably?
I have yet to receive details about AF with Tamron's new piezo drive lens.
Manual focus, the MF assist function, and (with the release of firmware v.04) focus peaking, are available at all times, with every single lens you put on the NEXes, even handholding one in front of the camera. The switchover to MF assist magnification is not done automatically however, because the camera can't sense movements of the focus ring, like it can with E-mount lenses. With firmware version v.04 a feature called focus peaking was added, highlighting parts of the image that the camera deems "in-focus" in a user-selectable colour. Quite useful, and instrumental in the success of the NEX cameras.
So, in conclusion, what does the LA-AE1 adapter do, and what doesn't it do?
- fully automatic aperture control on all A-mount lenses, enabling all exposure modes.
- allow readout of lens specific data like focal length and aperture, to be embedded in EXIF image data.
- enable image stabilization on any A-mount lens with this feature.
- slow AF with the following Sony lenses (as of March, 2011):
SAL30M28 30 mm f/2.8 SAM DT macro SAL35F18 35 mm f/1.8 SAM DT SAL50F18 50 mm f/1.8 SAM DT SAL85F28 85 mm f/2.8 SAM SAL1855 18-55 mm f/3.5-5.6 SAM DT SAL24F20Z 24 mm f/2 ZA SSM SAL1635Z 16-35 mm f/2.8 ZA SSM SAL2470Z 24-70 mm f/2.8 ZA SSM SAL2875 28-75 mm f/2.8 SAM SAL55200 55-200 mm f/4-5.6 SAM DT SAL70200G 70-200 mm f/2.8 G SSM SAL70300G 70-300 mm f/4-5.6 G SSM SAL70400G 70-400 mm f/4-5.6 G SSM SAL300F28G 300 mm f/2.8 G SSM
- Autofocus on A-mount lenses other than those listed. This includes third-party A-mount lenses, even if they have focus motors.
- Switch to MF assist automatically when the focus ring is turned.
- There's no aperture control during live view. The background defocus function is disabled. An aperture other than the largest available won't show its effect until after you've taken the shot. Movie recording in A-mode does stop down to the selected aperture before starting a movie clip.
The following image gallery was shot entirely with the excellent and compact Minolta "pocket rocket" 135 mm f/2.8, the LA-EA1 and the NEX-5. This is a superb tele setup that I've used extensively.
Click thumbnails to zoom in. Click again to zoom out, or use cursor keys to walk through all images.
The same combo is also very well suited for the concert hall:
And finally, some shots of metal legends Immortal, shot from a considerable distance, in a venue where SLRs are not allowed: