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Minolta AF lenses on Sony A7 series cameras
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PostPosted: Tue Mar 09, 2021 8:09 pm    Post subject: Minolta AF lenses on Sony A7 series cameras Reply with quote
As I own a rather comprehensive set of old Minolta AF lenses and migrated some time ago from the Sony A850 to the Sony A7R II I've also bought the LA-EA4 adapter to continue with my old lenses on my new body.

However, as you might already know the AF functionality with old screw drive lenses is rather limited with this adapter and doesn't support all the new fancy AF features and reduces the light due to an additional mirror in the adapter.

Luckily a Chinese group of people developed a tweak to modify such LA-EA4 screw drive adapters to get rid of the mirror and use all the existing AF functionality of the camera.

I've ordered this replacement chip from China and received it today. It's called "Monster Adapter LA-EA4r". It turns the LA-EA4 into a LA-EA3 for screw drive lenses.

Conclusion: It's worth every penny and all my old Minolta AF lenses work almost as good like the new and expensive original Sony FE lenses.

Same is available from Sony now as well but only for the A7R IV and the new adapter LA-EA5 (NOT working with older or other models). For my taste far too expensive compared to the monster adapter solution which is available for almost every LA-EA4-compatible camera; particularly as I don't have any plans to migrate to this new camera as long as my A7R II is up and running.

Maybe this information is of some use for other SONY FE shooters as well....

Cheers,

Last edited by tb_a on Tue Mar 09, 2021 10:00 pm; edited 1 time in total


PostPosted: Tue Mar 09, 2021 8:42 pm    Post subject: Reply with quote
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PostPosted: Mon Apr 12, 2021 8:18 pm    Post subject: Re: Minolta AF lenses on Sony A7 series cameras Reply with quote
tb_a wrote:
As I own a rather comprehensive set of old Minolta AF lenses and migrated some time ago from the Sony A850 to the Sony A7R II I've also bought the LA-EA4 adapter to continue with my old lenses on my new body.

However, as you might already know the AF functionality with old screw drive lenses is rather limited with this adapter and doesn't support all the new fancy AF features and reduces the light due to an additional mirror in the adapter.

Luckily a Chinese group of people developed a tweak to modify such LA-EA4 screw drive adapters to get rid of the mirror and use all the existing AF functionality of the camera.

I've ordered this replacement chip from China and received it today. It's called "Monster Adapter LA-EA4r". It turns the LA-EA4 into a LA-EA3 for screw drive lenses.

Conclusion: It's worth every penny and all my old Minolta AF lenses work almost as good like the new and expensive original Sony FE lenses.

Same is available from Sony now as well but only for the A7R IV and the new adapter LA-EA5 (NOT working with older or other models). For my taste far too expensive compared to the monster adapter solution which is available for almost every LA-EA4-compatible camera; particularly as I don't have any plans to migrate to this new camera as long as my A7R II is up and running.

Maybe this information is of some use for other SONY FE shooters as well....

Cheers,


That is helpful indeed. Did you notice much focus shift on Minolta AF lenses? That would partially defeat use of autofocus if stopping down the lens results in incorrect focus plane.


PostPosted: Mon Apr 12, 2021 11:58 pm    Post subject: Re: Minolta AF lenses on Sony A7 series cameras Reply with quote
lumens pixel wrote:
Did you notice much focus shift on Minolta AF lenses? That would partially defeat use of autofocus if stopping down the lens results in incorrect focus plane.


No, not really. All in all the usage of the original LA-EA4 wasn't too bad. However, the modified adapter with the "Monster"-chip works much better although there are some limitations as well which may be cured on later firmware releases.
You may study the user comments (including mine) here: https://www.facebook.com/groups/572060616797245

You may also find a user survey there where all approved lenses are listed.

My best combination is the "AF 420mm/F5.6 H.S. APO" as shown here (you may have some ideas about the price of a comparable lens in original E-mount):



PostPosted: Tue Apr 13, 2021 2:31 pm    Post subject: Reply with quote
Quite impressive.

Glad to hear no focus shift. I have red here or on another forum that it was not possible to autofocus at working aperture with the adapters which is not an issue in the absence of focus shift.

Thanks for the information.


PostPosted: Tue Apr 13, 2021 3:05 pm    Post subject: Reply with quote
lumens pixel wrote:
Quite impressive.

Glad to hear no focus shift. I have red here or on another forum that it was not possible to autofocus at working aperture with the adapters which is not an issue in the absence of focus shift.

Thanks for the information.


Well, with the Monster-Modification focus shift is impossible because AF is regulated by the camera instead of the adapter; i.e. it works like an original E-mount lens with all available AF-modes of the used camera.


PostPosted: Tue Apr 13, 2021 3:57 pm    Post subject: Reply with quote
That is unclear to me. Of course there is no need for micro adjustments of AF since focusing occurs on the sensor without any mirror.

However when you prefocus the lens is wide open even though you have selected let us say f5,6. Then you fire the shutter and immediately before sensor recording the diaphragm is closed to f5,6. My point is that there is no refocusing between the prefocus and the shutter fire so if the lens has a different focus setting because of the closed diaphragm there will be no adjustment.

I have noticed that on most of my MD lenses there is a difference in focus when closing the diaphragm and was inquiring whether Minolta changed the conception of the lenses when transitioning to AF.


PostPosted: Tue Apr 13, 2021 4:20 pm    Post subject: Reply with quote
OK, obviously I misunderstood you. I was referring to the focus adjustment for the LA-EA4 adapter feature which is available in the A7R II.

No, I definitely never realised this phenomenom you are describing. With no lens that I own.

However, I'm using only original Minolta AF lenses, primarily primes. Maybe 3rd party lenses are working differently.

Do you have any information of a specific lens where this may occur?

Another good option is the usage of the Techart PRO AF adapter, works perfectly well with all my Minolta MC/MD lenses. It also uses the camera's AF system but at working aperture. At low light with smaller apertures this may be problematic in comparison to the open aperture AF functionality of the Sony adapter.


PostPosted: Tue Apr 13, 2021 5:30 pm    Post subject: Reply with quote
No problem, maybe I was not clear myself.

Sure MD lenses on a Techart solves the problem. But I was wandering if some nice AF lenses that are quite cheap with no equivalent in the MD line would be worth considering.

For example the 28-135, the 100-200 4,5 and the 28, 35 F2,0 or the 85 and 100.

These are not very expensive by today's standards and with no exact MD equivalent even though you could find perfectly fine MD lenses of same focal lengths.

However it would have ruined the experience to look for very sharp lenses subject to focus shift, hence my question.

If someday you have the time to manual focus at working aperture and compare with the AF result it would certainly be of interest.

I could understand that Minolta tried to diminish the focus shift issues turning to AF so the problem might be reduced compared to the MD line.

I noticed that Canon FDs have comparatively much less focus shift than the corresponding Minolta's, reason why perhaps many consider the latter less sharp.

Thanks anyway for your attention.


PostPosted: Tue Apr 13, 2021 6:55 pm    Post subject: Reply with quote
I have following Minolta AF lenses in use and I've never noticed the "focus shift" problem, neither on my Sony A850 nor if used adapted on my A7R II.
20/2.8, 24/2.8, 28/2.8, 35/2, 50/1.4, 85/1.4, 80-200/2.8 HS APO, 300/4 HS APO, 500/8, Tele Converter 1.4X APO II.
100-300/4.5-5.6 D APO and 24-105/3.5-4.5 D (small travel package).


PostPosted: Wed Apr 14, 2021 1:56 pm    Post subject: Reply with quote
tb_a wrote:
I have following Minolta AF lenses in use and I've never noticed the "focus shift" problem, neither on my Sony A850 nor if used adapted on my A7R II.
20/2.8, 24/2.8, 28/2.8, 35/2, 50/1.4, 85/1.4, 80-200/2.8 HS APO, 300/4 HS APO, 500/8, Tele Converter 1.4X APO II.
100-300/4.5-5.6 D APO and 24-105/3.5-4.5 D (small travel package).


Thank you. I have the MD 28 2,8 5/5 which I believe is the same computation than the AF and is a very nice lens. I wonder if the MDIII 50 1,4 7/6 is the same as the AF. Also a very good lens.


PostPosted: Wed Apr 14, 2021 2:21 pm    Post subject: Reply with quote
lumens pixel wrote:
I have the MD 28 2,8 5/5 which I believe is the same computation than the AF and is a very nice lens. I wonder if the MDIII 50 1,4 7/6 is the same as the AF. Also a very good lens.


Well I've got quite many SR-Mount lenses as well, incl. the MD 28/2.8 in both versions and the MD 50/1.4 in the latest computation. Indeed both last MD versions are almost indistuingishable from the AF versions which share the same constructions.


PostPosted: Mon Jul 03, 2023 4:55 am    Post subject: Reply with quote
Hello, I am watching a cheap af apo 200mm 2.8 Minolta, but I'm not sure a dumb af -nex for the A7II would work for this lens . As you can see, I have no experience with these af lenses on Sony neither their adapters. The lens it's got a fungus and dust , that's why is so cheap , dunno how easy is to disassemble and clean .


PostPosted: Tue Jul 04, 2023 4:12 pm    Post subject: Reply with quote
The "dumb" MinAF=>Sony E adapter will work. Of course you'll hae to focus manually, and you'll have to set the aperture manually as well (on the adapter, not on the camera). I have the MinAF 2.8/200 APO and occasionally do use it on the A7RII, with a dumb adapter.

That said, dismantling and cleaning the MinAF 2.8/200 might not be that easy - especially if you want to keep its excellent optical performance! Back in its time, the larger "white" Minolta APO lenses (such as the MinAF 2.8/300 APO or the MinAF 4/600mm APO) were serviced exclusively in Japan, by the very person who actually built the new 2.8/300 and 4/600 lenses. Minolta was well aware that servicing theses lenses properly was a tricky work. Why do I know this? The former head of Minolta Switzerland's repair service told me this, back in 2010.

S


PostPosted: Wed Jul 05, 2023 10:24 am    Post subject: Reply with quote
stevemark wrote:
The "dumb" MinAF=>Sony E adapter will work. Of course you'll hae to focus manually, and you'll have to set the aperture manually as well (on the adapter, not on the camera). I have the MinAF 2.8/200 APO and occasionally do use it on the A7RII, with a dumb adapter.

That said, dismantling and cleaning the MinAF 2.8/200 might not be that easy - especially if you want to keep its excellent optical performance! Back in its time, the larger "white" Minolta APO lenses (such as the MinAF 2.8/300 APO or the MinAF 4/600mm APO) were serviced exclusively in Japan, by the very person who actually built the new 2.8/300 and 4/600 lenses. Minolta was well aware that servicing theses lenses properly was a tricky work. Why do I know this? The former head of Minolta Switzerland's repair service told me this, back in 2010.

S


If these were APO lenses with a calcium fluoride (CaF2 = fluorite) element then that would be another good reason for having them cleaned by a specialist. A CaF2 element used in an APO tele-lens isn't glass, it is a monocrystalline salt that is ground and polished like glass, but has superior dispersion properties to glass. BUT: it is very soft and easily damaged, that is why it is always fully encapsulated in a lens group protected by other glass elements. Never attempt to clean a CaF2 element yourself.
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