Adapting from dSLR to Mirrorless
All three of the big camera brands have now progressed in the move from dSLR to mirrorless. Canon and Nikon both started making autofocus SLR cameras in the 1980’s. Minolta was actually the first to start autofocus SLRs in 1985 and their “A-mount” was taken over by Sony in 2006. You had three major brands, each with a different lens mount. Sony/Minolta utilized the A-mount, Nikon had the F-mount which was continued from their pre-autofocus days. Canon started an entirely new all-electronic mount for the autofocus era, the EF mount.
When SLRs when digital in the 2000’s, these three camera companies continued with the same mounts. Over 30 years, they built up libraries with dozens if not hundreds of lenses. (In addition, third party lens makers added hundreds more).
A major concern of switching to mirrorless has been preserving continuity for customers as opposed to telling them that every lens they have collected over the last 30 years is now worthless. Thus, every camera maker has come up with adapter solutions to make lenses compatible with a new generation of mirrorless cameras.
Because of the shorter flange distance of mirrorless cameras as opposed to dSLRs, it’s rather easy to adapt lenses. At least to the extent of using them as basic manual focus lenses. Giving them fuller functionality is more challenging.
Sony was at the forefront of the transition from dSLR to mirrorless. Probably because they were a distant third in market share, they had the most incentive to shake things up with something new. For many, one joy of the Sony Alpha mirrorless system is the ability to adapt old lenses from other systems. Yet, ironically, Sony serves their former dSLR customers far worse than Canon and Nikon in terms of adaptability. Despite being the first to the market, they actually have the worst adaptability of their old mount. This post will address the issues with the Sony A-mount adapter.
Adapting on Early Sony Mirrorless Cameras
Early mirrorless cameras used autofocus systems entirely different than dSLRs, requiring very different lenses. dSLR autofocus systems utilize phase detect, wherein the focus distance is measured and the lens is directed quickly to that point. Early mirrorless used contrast detect autofocus, which measures correct autofocus by trying to maximize the contrast. This requires a lens focus system to quickly shift back and forth in the search for maximum contrast. Old SLR/dSLR lenses simply weren’t designed for the quick back and forth shifting required for contrast detect autofocus. Thus, these olders lenses simply were not truly compatible with autofocus systems that relied on contrast detect.
In addition, Sony and Minolta had been very slow in updating their lenses from screw drive to internal focus motors. Virtually every Minolta lens and about half of all Sony lenses used a screw to adjust the focus. The camera body had to have a motor, and the motor in the camera body would turn the lens screw to adjust the focus. In the modern era, most cameras makers were moving to lenses with an internal focus motor. Every single Canon EF lens uses an internal motor. Nikon has been using internal motors since the late 1990s. For Sony, of the A-mount lenses on the market today, many still use the screw drive.
When Sony launched their first mirrorless cameras, they created a new mount, the “E-mount.” The early mirrorless cameras were generally branded as the “NEX” cameras while the “Alpha” designation generally referred to the Sony dSLRs. But to make both mounts into one happy family, Sony released two adapters:
Sony A-mount Adapter
LA-EA1: This was a simple pass-thru adapter, adjusting the flange distance so that A-mount lenses could take photos on an E-mount camera. The adapter has electric contacts and aperture lever, so you could control the exposure and aperture through the camera body. This was primarily meant to be a manual focus adapter. There was no motor to adjust screw drive lenses. Since there were electronic contacts, autofocus information could be relayed to the lens. If the lens had an internal focus motor, it could therefore autofocus but autofocus was extremely slow when using contrast detect on those dSLR lenses. In most cases, you were probably better off using manual focus even if the lens had an internal motor.
LA-EA2: Wonderfully, this adapter magically allowed autofocus on virtually every A-mount lens ever made. Except, it really wasn’t magical at all. The LA-EA2 was not a pass-thru adapter. Quite the contrary, it was essentially a chunk of one of Sony’s SLT camera systems. The adapter had a translucent mirror inside, meaning your mirrorless camera was no longer mirrorless. The translucent mirror would reflect part of the image to a dSLR-type autofocus system within the adapter, which would use phase detect autofocus. The adapter had it’s own motor so it could be used with screw drive lenses. Effectively, the autofocus system of the mirrorless camera was being entirely overridden by the adapter.
When Sony went full frame with mirrorless in 2013, they simply updated those two adapters to accommodate a larger image circle, LA-EA1 became LA-EA3 and LA-EA2 became the LA-EA4.
Evolution of Mirrorless Adaptability
Quickly over a few years, autofocus systems in mirrorless cameras improved dramatically. From hybrid systems that used both phase detect and contrast detect to current systems that can primarily or completely rely on phase detect autofocus systems.
As a result, you can now take that LA-EA3 adapter and a Sony A9/A7iii/A7riii, and get fast precise autofocus with any A-mount lens that has an internal focus motor.
Since Canon and Nikon are both launching their cameras now, their mirrorless cameras already have excellent phase detect autofocus systems. (The Canon R exclusively utilizes phase detect AF while Nikon Z cameras use a hybrid system that primarily relies on phase detection).
Canon R System Adapter
Canon has launched with three versions of an adapter. Canon’s EF-EOS R adapter, priced under $100, promises seamless adaptability to every Canon EF lens. EF lenses will behave virtually the same as a new mirrorless lens, when mounted on the Canon R. Since every Canon EF lens is fully electronic and since every Canon EF lens has an internal focus motor, the adapter essentially just needs to adjust for the flange distance of the mirrorless camera. (Canon also is offering other more expensive adapters that add extra functionality including drop-in filters and a control ring adapter).
Nikon Z Adapter
Nikon was in a slightly more difficult position. They have used the F-mount for over 50 years. Many lenses in their library are still old manual focus lenses or screw drive lenses. Nikon has been moving away from screw drive lenses — most of Nikon’s aps-c bodies no longer have screw drive motors. I believe every autofocus lens Nikon has released in the last 20 years has an internal focus motor. So it wasn’t a shock when Nikon decided to release an adapter that only fully supports lenses with internal focus motors. For lenses without internal focus motors, the Nikon FTZ adapter is limited to manual focus.
Every current Nikon F-mount lens has an internal focus motor. Overall, Nikon claims full autofocus and auto-exposure support for 90 lenses in their library. Nikon’s FTZ Adapter is priced at $250 but $150 when bundled with the camera. For an investment of $150 to $250, a Nikon Z camera buyer can give themselves the availability of an additional 90 lenses with full or near-full functionality.
Sony’s LA-EA1/3 Adapter
Sony’s LA-EA3 adapter works just like the Nikon FTZ and the Canon EF-EOS R adapters. It is priced similarly at under $200, Since Sony’s newest mirrorless cameras have advanced phase detect systems, the LA-EA3 becomes a pass thru adapter that allows the lenses to obtain nearly full mirrorless functionality. Eye-AF, Af coverage over 90% of the frame, and other features now become available along with quick and accurate autofocus. (Read about Eye-AF here).
As with the Nikon FTZ, the adapter only will provide all of this autofocus functionality if the lens has an internal focus motor. But while Nikon has been upgrading their lenses to internal focus motors for 20 years, Sony was slow to make this transition. Sony lists their A-mount lens adaptability here. So while the adapter is similar in theory, it only supports a small fraction of the number of lenses.
Adaptable Lenses
As shown on the compatibility page, there is a massive library of A-mount lenses, past and present. By my count, there are 136 A-mount Minolta and Sony lenses. Unfortunately, only 28 of the lenses have internal focus motors. Of those 28, 9 of them are APS-C lenses. So if looking to adapt lenses on to a Sony A9, A7riii or A7iii, there are only 19 Sony/Minolta lenses with internal focus motors. Making matters worse, many of those lenses are essentially minor upgrades or re-badging of the same lens. (Minolta 70-200 F/2.8 G SSM, Sony 70-200 F/2.8 G SSM, Sony 70-200 F/2.8 G2 SSM, for example).
In total, only 11 unique Sony/Minolta A-mount lenses can be adapted to Sony mirrorless cameras with the LA-EA3 adapter. There are some additional third party lenses as well but third parties have largely stopped supporting the Sony A-mount.
It’s not just really old A-mount lenses that can’t be adapted. Some of the current premier professional A-mount lenses lack an internal focus motor, like the Sony 85mm F/1.4 Zeiss lens or the Sony 135mm F/1.8 Zeiss. Sony A-mount macro lenses all still lack an internal focus motor. Thus, even recent and current Sony A-mount users own lenses that cannot be adapted with the LA-EA3. For those sitting on a collection of Minolta/Sony lenses, you shouldn’t expect easy functional adaptability.
Of course, as I mentioned earlier, Sony did give us the LA-EA4 adapter which does provide autofocus to all 136 of these lenses… but…
Limitations of the LA-EA2 and LA-EA4
The LA-EA4 adapter tosses aside the autofocus system from the mirrorless camera. That means you can’t use the hundreds of autofocus points on the A9, A7riii or A7iii. It means you can’t use Eye-AF. You can’t use focus tracking or focus modes like flexible spot. You can’t use the 90% AF coverage of these current full frame cameras. Forget about using the high burst shooting available on these cameras.
Instead, you are stuck with a circa 2010 dSLR style autofocus system. DSLR and mirrorless autofocus systems have both come a long way since 2010 but you are stuck with a terribly outdated autofocus system. It’s not even a full frame autofocus system. It is the autofocus system pulled right from the aps-c camera, Sony A55. Only 15 focus points, all bunched up in the middle of the frame. Only 3 cross points. One shouldn’t expect great low light autofocus.
Translucent Mirror Limitations
Making matters worse, you get all the limitations of Sony’s SLT, translucent mirror, technology. When shooting video, aperture is locked wide open. The translucent mirror further eats away light. To get proper exposure, expect to use higher ISO. Ultimately, you are losing about 1/3rd to 1/2 stop of light. In terms of light gathering, using a 2.8 lens with the LA-EA4 is no better than using a native lens with F3.5 aperture. Your adapted 70-200/F2.8 becomes barely better than a 70-200 F/4.
Sony prices the LA-EA4 adapter at $350. For $350, you can get the privilege of converting my premium modern Sony A9/A7riii/A7iii into a 2010 aps-c dSLT camera. You’ll get superior autofocus by just buying a modern A-mount camera like the Sony A68, priced around $600. You can avoid the light loss and get full frame benefits by buying an old used Sony A900 or Sony A850.
While a Nikon or Canon shooter can give new life to dozens or hundreds of lenses by adapting them to mirrorless, a Sony user has to take a step backwards to 2010 SLTs to adapt most A-mount lenses.
The Irony for the Sony Adapter
I shot with the Minolta and Sony A-mount for many years. One of my favorite lenses of all time is the Minolta AF 200mm f/2.8 APO G HS. It is an ultra sharp lens with beautiful contrast and rendering, even at 30 years of age. Compared to modern 70-200 F/2.8 lenses, it is extremely light, weighing only 790 grams.
Here is the irony: Canon also has a 200mm F/2.8 lens. Bought used, it’s probably a little cheaper than the Minolta version. It’s similar in size and weight. Unlike the Minolta lens, it has a silent internal focus motor. With a Metabones adapter, I can get mirrorless functionality with this lens on my Sony body. For example, eye-AF is one of the best features on Sony mirrorless cameras. On a Sony body, I can do it with the Canon lens but not with the A-mount lens. If you’re a Sony shooter who wants to expand the options of available autofocus glass, you’re better off buying an adapter for Canon EF lenses then trying to adapt Minolta lenses!!!
Sony Should Update their Adapter
If Sony has any interest in preserving their inherited A-mount legacy, including converting the remaining A-mount customers to the E-mount, they desperately need to fix the adapter issues.
My preference would be to see Sony do a pass thru adapter like the LA-EA3, but with screw drive support. It would allow those screw drive A-mount lenses to use the wide AF coverage of the mirrorless cameras. It would eliminate the light loss of the SLT mirror.
At a minimum, Sony should update the LA-EA4 to include a more modern autofocus system. Instead of using the 2010 AF system of the Sony A55 they should use the 2016 AF system of the Sony A99ii. A system that is designed for full frame, that supports hybrid AF wherein it makes some use of the on-sensor autofocus points to improve subject tracking. It supports eye-AF.
Why Sony Probably Won’t Fix the Adapters
Unfortunately, I fear Sony has no interest in improving adaptability for A-mount lenses. The Sony A-mount user base has shrunk so small that I’m not sure Sony cares much about trying to convert them. Further, Sony wouldn’t want to provide any incentives against investing in their new expensive FE lenses. Why would Sony want you adapting your excellent A-mount 100mm F/2.8 Macro, when they would rather sell you a new excellent FE 90mm F/2.8 macro?
Conclusion
Does it even matter anymore? Sony now produces about 25 native FE full frame lenses. Sigma, Tamron, Samyang and Zeiss produce dozens more. There are very few remaining gaps in the Sony FE mount lineup.
While there may be sufficient premium modern choices for Sony shooters, I object to the disconnect with the Sony Alpha past. It is unlikely that Sony ever makes another A-mount camera body, with the last two bodies coming in 2016. But the proud lineage of A-mount glass doesn’t need to be buried.
Old time A-mount shooters are poorly served by Sony’s current adapter solutions. While the adapter choices made sense in 2010, they don’t make sense today. I encourage those who want to use A-mount glass to speak up. If you come across a Sony manager, make your voice heard…. WE WANT BETTER ADAPTERS!!!!!
