Danger of G lenses?

I was browsing macro lenses, looking at the 100mm lens and the 200mm G lens. Thats when I was told about an issue with G lenses and their grease having hardened over the years to the point it’ll actually break your cameras AF drive. My question is there anyway to test a lens for the hardened grease without risking your camera?

Who told you that ?

I've most of the Minolta lenses from the start of A-mount in 1985 , including quite a few G lenses .
200mm f/2.8 , first version , mid 80's . 300mm f/4 H/S and 300mm f/2.8 , first version , 400mm f/4.5 , 80-200mm f/2.8 G , white version . 85mm f/1.4 RS , early 90's .Sony 35mm f/1.4 G , 2006 onwards .
The grease is spot on in all of them .
I've never heard of the grease drying out in any Minolta AF lens .

I've a lot of manual focus Minolta SR mount lenses , and all of them focus correctly , non are stiff or with dried up grease .

The only lenses I've got that have had problems with their grease are some FSU lenses , who probably used some form of axel grease to lube them with .

With regards to A mount macro lenses , I've the Minolta 1-3X Macro zoom lens , the Minolta 50mm f/3.5 , Minolta 50mm f/2.8 RS , 50mm f/2.8 D and Sony 100mm f/2.8 ( same as the Minolta 100mm f/2.8 D ) and a Sigma 180mm f/3.5 .
All focus as intended and work well with all my A mount cameras , Minolta and Sony .

I've never heard of Minolta A mount lenses grease drying up and breaking the cameras AF . Can you provide a link to where you've read this ?


Edited by neilt3 - 24 October 2023 at 01:22

ToothyWeasel wrote: This was mentioned to me in a Minolta discord server while discussing potential lenses I was looking at, that’s why I was asking as I had never heard that before. There’s some posts on here from around 2016 talking about how the grease gets pretty gummy and strains auto focusing motors like in this thread: https://www.dyxum.com/dforum/minolta-2870-g-ageing-issues-needs-replacement_topic123348_page1.html

I've only read the first few posts, but the opening post of that thread has nothing to do with what you asked .
It's talking about a sticking aperture .
Nothing to do with focus , be it AF or MF .

There should be no oil or grease on the aperture to go hard in the first place .
A sticking aperture won't damage your camera or lens as as it just fails to stop down correctly giving overexposed images .

Oh and two other G lenses I have I forgot to mention were the 28-70mm f/2.8 G in that thread and the 17-35mm f/3.5 G .
Both of which also work fine .

I did have a 28-70mm who didn't focus to infinity , but clearly someone previously had had it apart and put it back together wrong .

Oh, and if you're still uncertain, pick up a el-cheapo Dynax/Maxxum 3, 4 or 5 - if that can drive the lens, your Dynax 9 for sure will.

Grease drying out is an issue with pre-80s lenses with organic grease. It can go solid and freeze focusing helicoids. The mineral grease used by Minolta, even in the early SR days, should last for centuries.