decisions

Sony's system has several choices for adapting A-mount (Minolta, Sony phase 1) lenses. Each does well when matched up with the 'right' camera and the 'right' lens. Does your lens have a motor? Is your camera body a 4th generation or 3rd, or 2nd? 

If some of your lenses have motors and some don't .. well, you need to sort out your priorities!

So here's my main two options:

• Current: LA-EA3 + a fully functional Tamron SP 70-300. I also have the native Sony 28-70oss, and Minolta zooms that work but without AF.
• Plan B: LA-EA4 would provide AF for the Minoltas 24-105, 70-210ii and 100-300 .. which means louder AF and a mere 4mm extra AF coverage (24-28mm). The Tamron would work fine with the ea4 - but only by using the more limited AF points of the ea4.

Most of my long shots are not AF dependent (e.g. Birds on Branches), and I'm old enough to remember how to pre-focus for the occasional BiF shot. 

I've heard the Tamron+ea3 has excellent image quality, for many users as good or better compared to their 100-300 Apo, but adapted lenses' performance is still short of native E-mount lenses.

The ea4 uses SLT tech and an infamous screw drive. How loud is it, and how versatile for manual focus? Some owners have reported that occasionally their AF pin stays in the lens, which limits MF; it seems to have a DMF setting which would retract the AF pin though. A dyxum post suggests that their ea4+ssm pairing is more accurate at long focal lengths than ea3+ssm. 

The Tamron is over 220g heavier than the 100-300, including the ~50g adapter difference - and the 70-210ii would be a bit lighter (and brighter)! I must say: that savings is worth something. There's also the autocorrection of native E-mount images to consider; the 28-70oss definitely gets treated, but who can say about the 24-105?

A-mount lenses transmit aperture and focal length to the camera for stabilization and exposure, which is nice. That's a bonus over my third option (an adapted Pentax 70-300apo from Sigma) without a $350 adapter. For that amount I could put both ea3 and ea4 in my bag!

12/16 Update - I picked up an EA4 adapter and it's on the way. Guess the Tamron can depart..