TechArt LM-EA7 firmware update to Version 4


TechArt’s ‘Sony Leica AF adapter’, LM-EA7 has firmware update to Version 4.

It came out last year, Oct, but I did not have big expecation and OK-ish with Version 3 anyway,

so delay the update until I overcome laziness in the beginning of new year.   : -)

To my pleasant surprise, V4 made significant improvements.


Looking back V2 to V3 upgrade, here’s short story why I don’t expect much.

(1) Operation noise reduced at V3 when adapter barrel moving back and forth for AF

(2) AF speed did not get slower or at least not noticeable, but not improved either

(3) Booting time increased quite a lot (0.5 seconds -> 1 ~ 1.5 seconds) which is much inconvenient …


Summitar with Sony A7 II, through TechArt AF adapter


Version 4 upgrade

(1) Booting time returned to fast mode (1 to 1.5 seconds -> less than 0.5 second)

(2) Noticeably faster AF speed. But also AF operation noize increased. (It seems unavoidable as AF works in mechanical drive …)

(3) AF-C focus seems to be much improved & it will be tested more & thoroughly

AF-S (single AF mode) was good from the beginning & is good but AF-C (continuous AF mode) was somewhat unstable,

sometimes ‘front focus’ and sometimes ‘pin-point’… For user’s point, it is hard to rely on it.

With short test right after V4 upgrade, I found AF-C seems improved a lot.

Of course, it is highly depends on how fast the object move & how much you expect from this adapter    :- )

There are 2 more check points for LM-EA7


Focus error of LM-EA7 (mostly ‘front focus’ error)

I’ve been use TechArt adapter approximately 10 months, but some weeks ago I’ve shocked with focus error unexpectedly.

As mirrorless system, A7 II, I expect either it works pin-point accurate or fails AF entirely if light is too low, for example.

But after couple of month of using, I found ‘front focus’ symptom which makes photo looks off-focus slightly.

It happen especially when the adapter not used for a while…   Initially I thought it is a kind of firmware bug (V3 induced?).

But to make things more confused, the symptom disappeared while I tried to figure out what’s going on, trying 3 different lenses and on-off couple of times. But next day, the problem happen again and disappear after I on-off two or three times.

Then, I realize the adapter if stored couple of weeks without using, the moving barrel can be slightly more sticky than normal, thus generate positioning error in encoder. This is actually common symptom of mechanically moving cylinder systems. It needs warming up which is couple of times moving in and out to spread thin coated lubricants.



LM-EA7 + Nikkor 55mm f1.2


(Workaround solution) On& Off twice will resolve the issue most of time

When power-on, TechArt adapter moves the barrel about 4.5mm from infinite to closest position and retrieve encoder signal to get barrel position accurately. This is a part of initialization sequence (On-Off).

While the adapter kept for a while the lubricant of moving parts became slightly sticky, thus can not move exact position due to mechanical friction on cylinder or motor gear system.

In this case, turn off / on twice will make the barrel moves properly because first initialization removes stickiness of moving parts.

This symptom happen only in case the adapter stored for a while, I will monitor the symptom in V4 as well

Continues draining battery juice even the camera switched off …

When the camera is turned off, the adapter consumes battery continously. I don’t know why it designed like this but one clue is bluetooth module of the adapter works always no matter camera on or off….

This is much inconvenient, especially A7 II consumes higher battery rate to keep LCD monitor, Electric view finder, 5 axis sensor movement…etc

I hope this problem fixed in next update. Will check it out …..




TechArt LM-EA7 is excellent gadget who loves manual lenses but not always like manual focusing, or simply have old eyesight like me.

Yes, there are minor bugs, but can be overcome. Overall this is a GREAT adapter !!!



to be continue //








글쓴이 Leo_KHIMME

사진, 사진기, 렌즈, 여행, 새로운 곳, 새로운 기술 & 신산업혁명
대만 타이페이 > 네덜란드 아인트호벤 거주
Oldies but Goodies 오피넛 멤버