Minolta AF 28-135 F4-4.5 / Infinity problem?

I have the same issue with my 28-135. Every image registers as 60mm and the focus hunts from about 100 on up. The images are still very nice, but always need to operate in manual focus at the long end. I sent it to Precision Camera but they would not repair it. Any advice or possible solution would be appreciated.

CKsam2 wrote: Lahnet: Here's a possible solution. I'm guessing the lens just needs a very slight adjustment, and it's probably something you could try for yourself. If you unscrew the three screws on the metal collar where the distance scale is you can remove it by just slipping it over the back of the lens. See here. (Note that you do not need to have unscrewed the lens mount as Pete as done here). Underneath there is a piece of tape holding together two rings. You should remove this. See here. Now mount the lens on the camera set in manual focus mode, zoom to 135mm and turn the upper of the two rings until the camera registers focus on something at infinity. Making sure the lower ring is locked as far to the left as possible restick the tape so that the two rings are joined together again lining up the infinity symbol on the distance scale with the 135mm symbol on the zoom ring. Then put the collar back on and the screws back in. It's an easy job! I hope that sorts it out for you. Sam

thanks very much! brought new life to one of my two 28-135mm.
glad i didn't dump it when it would not focus to infinity anymore (in tele position) after i had tortured it with some fast zoom action in macro mode.
i have to say though that i'm a bit surprised that Minolta relied on a simple tape for such a vital function. on the other hand it worked for over 20 years on this lens before i came and... oh well, glad it works again.

I only just found out that my lens always thinks it's zoomed at 60mm, could that explain the AF issues? I disassembled the lens again and was wondering if my encoder is broken. I can see a couple of fingers that I think should slide on the encoder contacts. But only one of the five fingers is bend so that it could touch the contacts. The other fingers are 2 mm away. Should I try to bend these onto the contacts? It's all very fragile and not easy to reach.

Thanks

I have had simmilary problems with 28-135, what I bought for little money: I have tried to disamble and remove some internal shims for focusing to infinity, but then the lens can´t focuses right at 28mm between 3-6m, so I have tried all combination (2 or 3 shims, from my other 28-135 lens) but I wasn´t abble to setup correct focusing :(

http://artaphot.ch/lens-reviews/199-minolta-af-zoom-28-135mm-1422-45

Lahnet wrote: Sorry for the English :-) I have just bought a Minolta AF 28-135 F4-4.5 lens on eBay. When I use it on my Sony A100, it can not focus infinity between 100-135mm. There is no problems when i focus on closer objects, or between 28-100mm. The problem is the same on MF and AF.

This is a very common problem not only for the MinAF 28-135mm, but also for most other MinAF zooms of the first (beercan) generation. Even primes such as the 2.8/20mm and the 2/35mm usually are not REALLY focusing to infinity. I have corrected re-adjusted many of my MinAF lenses ...

Stephan

I´ve got the 28-135mm with the infinity problem, I´ve tried this and it worked BUT.

"...Now mount the lens on the camera set in manual focus mode, zoom to 135mm and turn the upper of the two rings until the camera registers focus on something at infinity. Making sure the lower ring is locked as far to the left as possible restick the tape so that the two rings are joined together again lining up the infinity symbol on the distance scale with the 135mm symbol on the zoom ring. Then put the collar back on and the screws back in. It's an easy job!"

I now got infinity focus even on 135mm!

Unfortunately i still have a problem; I can´t focus on anything between infinity and 2m between 100mm-135mm(it hunts like crazy.) What´s wrong? I´ve tried the above several times, but with the same result. There are now problems below 100mm.

madcat207 wrote: Sam - it does indeed show the correct Exif data. And thank you for clearing up the rest!

That's a shame, actually, as I don't know what else could be causing problems with the AF. Sometimes if contacts get bent inside the lens mount the exif data can be messed up and the lens will hunt backwards and forwards before finding focus. But, as your exif is OK that won't be the problem.

I guess you'll just have to cope with it as it is, although I'll keep thinking...

Sam