Play in Focus Ring of AF 35-70 f2.8

I just purchased a used AF 35-70 f2.8 and have some questions. The focus ring has some play in it along with some mild clicking.

 

Will this play and clicking hurt focus or other image qualities? Is this a sign that the lens is prone to break in some manner down the road?

 

Thanks!

I bought my 35-70mm/f2.8 AF lens way back in 1990. Since it is a push-pull zoom, initially the outer barrel seemed to scratch the inner one such that some very fine "power" was left behind on the inner barrel each time I zoomed. Back then there was the Nikon House in the Rockefeller Center in New York City. I took the lens there and a technician inspected it. He said I should send the lens to Nikon in Long Island, New York for warranty repair.

 

After that, the lens had been working fine until some inner element fogged up and the lens became pretty much useless since the contrast became very low. Instead of repairing it, I ended up buying a 28-70mm/f2.8 AF-S instead. That internal fog up problem seems to be quite common for the 35-70mm/f2.8.

"That internal fog up problem seems to be quite common for the 35-70mm/f2.8."

 

- Quite common on some older Sigma lenses too, and I've seen a couple of cheap Canon tele-zooms affected as well.

 

I believe it's due to the use of moulded plastic (or resin) elements in those lenses. When I've examined the affected elements closely, the 'misting' appears to be fine surface crazing that's impossible to clean away.

 

I haven't had a 35-70 Nikkor apart to confirm it has the same problem, but it certainly sounds like it.

 

Most annoyingly, my old Sigma AF f/2.8 70-210 zoom is showing the 'mist'. This lens used to have very good image quality until the degradation set in.

Oh, I wondered what could be causing a misting effect. Not that this seems to be Neil's problem, but it's useful to know.

The 'mistiness' can be quite subtle, while still lowering contrast significantly. The penlight test is very revealing of lenses with this problem.

 

Maybe Neil's lens is affected and it's not been noticed?

 

I'm mentally composing a black list of lenses with crazy plastic optics - most of them date from around the late 1980s to 1990s, and a good many of them come from Sigma. I wouldn't touch those lenses with a barge pole.

Four replies without any bearing on the OP's question. :)

 

Does it focus correctly with AF? If so, I would not really care. There is only mechanics involved on the lens side and it is only natural that cogs have been worn down over time. I would test its focusing capabilities at F2.8 at 35 mm and 70 mm at close range. It would not consider said play as a sign of it breaking down any time soon, only that with much use, it will become increasingly more difficult to hit 100 % focus all the time.

In my defence, t least I admitted my reply was irrelevant. :-)

 

I don't have much personal experience - I had a Sigma 150mm whose focus failed, but not in this way. Going off some of the lens tear-downs from Roger Cicala at LensRentals, my guess would be that play would be annoying if you're using manual focus, but otherwise it's probably harmless. The clicking worries me a bit. But I'm not really qualified to know whether that's a sign of something broken, or something wearing. Whether it's worth the cost of tearing the lens down I can't say. (If I was more qualified to comment, I would have done more helpfully!)

I thought about the OP's question and checked the barrel of my lens. The push-pull zoom motion is still smooth and I don't feel there is any "play" between the inner and outer barrels, but I am not sure what kind of play the OP is experiencing. There is certainly no clicking sound.

 

Concerning the internal fogging, again I bought the lens new in 1990 and that fogging happened fairly quickly in 2002, perhaps within a few weeks. However, now 15, 16 years later, it has not gotten worse.