Minolta 28-70 G - ageing issues needs replacement

If it's just a spring problem, and you can't get parts... then consider getting a parts lens. Remove the rear mount and steal the spring.

The consistency of aperture closing should have nothing to do with aperture arm on camera. It just releases and allows the lens spring to close it down.

If you're having a focus ring stiffness issue, then the AF drive from the camera can indeed play a factor. I don't accept that a99 drive shaft motor is less robust than a900 drive shaft motor. Or that a99 was designed for SSM lenses over screwdrive. a900 was released with SSM lenses and a99 release had many screwdrive lenses available when new.

I think it more likely that your a99 drive shaft motor is wearing out. I haven't had issues with a99. But I burned out two a900 drive shaft motors. One still worked but was very clacky sounding.

The Mino G 28-70/2.8 is easy to disassemble. From the rear, you have to go pretty deep to get to the focus ring gearing. You'll find a couple of gears that need pulling out, cleaning, and new greasing applied. The old grease gets gummy and makes the ring turn very stiff, which is hard on a camera motor. I used lightweight white lithium grease from a bicycle repair shop. just a dab will do ya, and the ring turns very smoothly. I washed my gears with a toothbrush in soapy water. Let dry fully before reassembly.

A good replacement choice would be the Minolta 28-75/2.8.

Edited by Photosopher - 21 November 2016 at 03:06

I had a 28-75 Sony SAM motor driven lens that was pretty good but I eventually picked up a used 24-70 SSM from KEH. I think I have $1100 for it so it was reasonably competitive to the new Tamron and is fully compatible with all of the A99 and A99ii focus functions. KEH has been running some really good deals lately so you could probably get one with a bit of a warranty from them for less than $1k if you're patient.

Photosopher wrote: A good replacement choice would be the Minolta 28-75/2.8.

The Tamron/Konica Minolta/Sony 28-75/2.8 is considered a good lens for the price. I never heard anybody who liked the 28-70/2.8G describe the 28-75 as "a good replacement choice". The 28-70/2.8G is a very special lens, with some downsides but specific upsides. The 28-75/2.8 (Tamron, KM or Sony) is lousy in the corners and not that good wide open. It is a good lens for the price, but other lenses are better and it surely misses the character of the 28-70G.

Another copy of your 28-70/2.8G will set you back about €500,-.
A used Sony/Zeiss 24-70/2.8 is about double that. It has the added advantage of having SSM and you can use all focuspoints on the A99ii. The Zeiss has, however, a different character then the Minolta G-lenses.

Disclaimer: prices from reputable stores in The Netherlands with warranty.

der dickgg wrote: A very good and yet not to expensive replacement to consider is the Tokina 28-75mm f2.8 ATX-Pro. Built to last forever and very good optics.

Completely agree, except that it's actually 28-70mm f/2.8. An understandable mistake, given the KM/Sony/Tamron 28-75/2.8 was just mentioned.

EDIT: Also, if the OP is bothered by an older lens with limited availability of replacement parts, the Tokina may not be the way to go.

Oh, what fun; I was rummaging in my old camera cupboard and found an old Minolta 35-105 mounted on one of my first Minolta 900's... I remember buying it before I purchased the Minolta 28-70 G some - 29 years ago! Tried it and found it in perfect working condition. Tomorrow, I'll take it out for some more trial shots to see if there is no fungus inside (there shouldn't as the room I keep this stuff is not humid). Anyone been using one lately ? How does it work ? Maybe I can temporarily skip getting the SAL2470Z2 in order to first get the A99ii...

Parker wrote: Oh, what fun; I was rummaging in my old camera cupboard and found an old Minolta 35-105 mounted on one of my first Minolta 900's... I remember buying it before I purchased the Minolta 28-70 G some - 29 years ago! Tried it and found it in perfect working condition. Tomorrow, I'll take it out for some more trial shots to see if there is no fungus inside (there shouldn't as the room I keep this stuff is not humid). Anyone been using one lately ? How does it work ? Maybe I can temporarily skip getting the SAL2470Z2 in order to first get the A99ii...

I find the af a bit slow and noisy but since most here disagree it's a personal opinion within parantheses coming from someone used to more modern silent options. People say it's sharp as a razor but mine isn't no matter how stopped down. "It's an old lens with lots of variation", yes, common argument, if that's the case then my dyxum stats in purchased equipment is like my ebay stat, which is OK.

It's sharp enough though and the colors it produces, specifically green, are very appealing indeed. So is the bokeh.

Way back when Minolta introduced this lens, they had high regards for it, pricing it 2nd only on their regular zoom line up to the secret handshake. I've owned and sold at least a dozen copies and never had a bad copy, just a couple with fungus. Here's a copy of my 1985 price list:

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