Pentax A 35-70 zoom - dud?

Hi

I recently picked up one of these lenses (Pentax SMC A 35-70 1:3.5-4.5) on eBay and the barrel and focusing ring both feel loose and rather wobbly. Is this typical for this lens or have I picked up a dud?

Thanks

Peter

I've got one that I bought new about 15 years ago.

The focus and zooming movements are fairly friction free (which is not great), but I wouldn't call it loose or wobbly.

I'm afraid that "rather wobbly" doesn't sound good for an A-series lens

R

Hi,
Loose and wobbly does seem rather common with these lenses. Pentax replaced to very good 35-70/4A zoom with these and they are notorius for having problems. The macro function is quite close on them but that is about their only good point.

Kim

Sound like I got a good one then

Thanks. It sounds like a dud lens, period (some samples excepted). And yes, the macro is really quite useable. It'll be a shame to see it go, but it feels so flimsy it's as though it's going to come apart in my hands.

A good SMC Pentax-A 35-70mm f4 is always worth having.

But these too can be rather loose is well worn. There are some good ones about and the quality is excellent, continuously focusing down to 1:4 magnification at the 70mm end.

I seem to remember using a piece of rubber plumbing pipe (coupling) that fit nicely arount the bezel around the lens....under the bezel (where the pentax name was printed) were a couple screws...tightening the screws and then the bezel tuned it right up. I liked that lens...

still use that trick on my 50mm

I don't quite understand - though I wish I did ...

im with you arto perhaps Don will go into a bit more detail or post a pic

will do....I'll make a video, and post a link...get back to you tomorrow ok?

sorry, work calls...can't do the video today, but heres some snaps to help you out....won't work with all lenses, just some...if my memory is correct it should work on the 35-70.

rubber pipe connector (plumbing shop)


carefully unscrew lens bezel


three screws under bezel


tighten screws (threadlock or nail polish can be used carefully to prevent them from loosening again)

Thanks for that Don i wasnt aware that bezel thing screws out
So if you remove those screws does that remove the front element :

On a very proportion of the Pentax lenses (and indeed many other makes), removing the front bezel is the first step in removing the front elements for cleaning. It is usually easier to go in this way as it doesn't upset the auto diapraghm which can be a PITA to get back together or the focussing.

The main exception is some of the later lenses and (mainly) some of the zooms. Generally these are the ones with the lettering around the outside at the front instead of being on the bezel.

This will fix some of the problems but unfortunately doesn't usually take up the slack in the zooming.

Kim

Thanks Don and Kim
The reason i ask is i have an F28-80mm which is a little wobbly at the front. But the 28-80 does not have the bezel. From what i can make out you unscrew the front element as you would the bezel on the 35-70 and i assume the screws that tighten it are under there : :

I think I have one at home. I will have a look and see if I can post something.

Kim