I recently got myself a Sony A7R III. To my surprise I found out that you could mount old a-mount lenses on the camera with an adapter and this sparked my interest. This is a review of the adapter and the a-mount lens I got for it. I want to find out if this is actually usable because there is some cool old a-mount lenses.
The a-mount is Minolta’s old lens mount later taken oven by Sony. A few years ago Sony made a new lens mount called e-mount and to help the old Sony users they made adapters to mount the a-mount lenses. For newer a-mount lenses you can use the cheaper and smaller Sony LA-EA3 adapter. But for the older lenses that uses the “screw driver” motor inside the camera to auto focus you will need the more expensive and bigger Sony LA-EA4 adapter.
I decided to get the Sony LA-EA4 together with a “Minolta High Speed AF Apo Tele 200mm f2.8 G New” lens. The lens is praised by many as one of Minolta’s sharpest lenses.
But why get this lens in 2019? Sony’s e-mount lens lineup has got a lot better the last couple of years but I still wish there was more long tele prime lenses. I ended up buying the Sony FE 70-200mm f2.8 also, but it’s very big and expensive. Sony has a 400mm f2.8 but the price is 14000$. There is also a newer Sony 300mm f2.8 for the a-mount (without screw driver auto focus) that can be used with LA-EA3, that should have close to native auto focus preformance, but it’s a also an expensive lens.
When you get the lens and the adapter the first thing you need to do is to adjust the auto focus. The Sony LA-EA4 comes with a reflective mirror inside (just like the old Sony a-mount cameras) and for all mirror cameras you should adjust the focus for each lens because the distance to the AF sensor is different for each camera and lens.
You can do this by going into the menu: in the first tab (camera icon), on the last page with AF settings (page 8 for A7R III) -> AF Micro Adj. Here you can choose to add/subtract to get the right focus. For me I had to enter -7 to get the right focus. You can figure it out by shooting something like a ruler with mm units on, focus on one point and see how much its out of focus. Or get a real camera calibration chart print. Google it, lots of guides out there.
A bad thing of the adapter is that the mirror blocks 1/3 stops of light, meaning you will have to raise your iso a bit.
A another limitation of the a-mount adapters is that you don’t have normal e-mount focus options. You are limited to a few focus points in the middle. Not a big deal you might think, but you are gonna miss object tracking, eye-AF and all the focus options you normally have. A deal breaker for me.
How does auto focus work?
In single focus: it works even though it’s a bit slow. For objects that don’t move you can use this lens and adapter combo.
In continuous focus: It will try to focus and refocus but it’s not something that is usable. The refocusing only happens ever 1-2 sec. meaning that all the shots in between is out of focus. Even worse is that sometimes it will completely miss focus and it will be very hard to focus back again. If you plan to get this for continuous focus, don’t get it. For the photos you see here I had to take a lot of other photos that was out of focus, not worth the time.
So how sharp is this lens?
Looking at the test shots the Sony is clearly sharper than the old Minolta. Also the Minolta has some bad color fringing that the Sony has nothing of. Sony seem to have a little barrel distortion, but only very little and something easy to correct.
Note: The Minolta almost seems softer at f9, I took several shots and auto focused each time, and all looks like that, so either it gets softer at f9 or maybe it’s just my copy.
My conclusion is that it is very usable and probably better than most lenses from the 80s. But why get such an expensive camera and put a unsharp lens on it? Maybe if you are a lens history geek or want some kind of different look. But for me after seeing these test shots I’m gonna stay away from old Minolta lenses.
- It’s a pretty small 200mm lens compared to all the other long tele options for Sony.
- Bokeh is very smooth.
- Minolta and old Sony a-mount lenses are pretty cheap.
- Auto focus is too slow and too unsable.
- Too primitive focus options.
- The mirror in the adapter block light and you lose 1/3 stop.
- Pretty sharp lens for such an old lens but not that sharp compared to modern lenses.
- Image rendition is a little bit 80s like. People say it has the Minolta look, not something I’m a big fan of. You often get color fringing and people get this extremely red look like they are bleeding out of their eyes. In post production you can often fix this.