Vivitar lens

Hi All,
I've been given a Vivitar 28mm 1:2 manual lens from the estate of an old Pentax photographer I once knew. His camera has been given to a relative.

The lens is in quite good condition considering its years but, whilst it will fit and operate on my MZ60 it will not even fit my K10D/K5.




The side is engrave P/K and has a Asahi Opt.Co end cap.

It has an extended 'shield' at the back and I'm puzzled

Comments/advise would be welcome

regards
Bernard

Hi Bernard, it is a well known issue with some of the old Vivitars. The extended shield is the problem of Pentax DSLRs. It is quite a simple fix.
1. Remove the small screws that hold the shield in place and carefully lift the shield away.
2. Cut or grind down the shield depending upon whether it is plastic or metal. Use a modern Pentax lens to gauge how much to cut away.
3. Make sure there are no rough edges and clean down well , before refitting to the lens.

Regards - Steve

Just to clarify, it isn't a problem with Pentax DSLRs but one due to Vivitar making their 'PK' lenses different to the Pentax K mount. Thus, when Pentax added the PowerZoom contacts in '91 (later used for SDM), some Vivitar lenses (I also have a Tokina too) won't fit.

Selected Pentax film bodies also have these contacts, namely the Z-1/Z-10 and some of the MZ line (including the MZ-M - which although it doesn't have the contacts, does have the lug used to attach them).

John.

Thanks Steve/John,

I suspected as much (I just wanted re-assurance)
Job done :-



Now need to try it out.

Out of curiosity - is this considered a good lens - or is it merely 'adequate'.

I was pleased to have been remembered and it may well be better than the cheap & cheerful Miranda 28 1:2.8 (M42) lens that I've had since the 70's

regards
Bernard

Further curiosity - what does the shield do?

There are a couple of versions of the Vivitar 28/2, made by different manufacturers. Have a look here:

http://photografica.robinparmar.com/vivitar.html

Mine is the K01, I think. Performance isn't bad on digital, better on film. It's not that great wide open and the coatings give images a very slight green tinge on digital, which is usually automatically corrected by the autom white balance of the camera. I haven't tried it yet on colour film but I like it on B&W and the extra stop of speed is nice.

Thanks Johnathan - I've bookmarked that link for future use.

Mine is a K11 type and on close examination I can see a very faint 'spiderweb' on the inside of the front element - I suspect the onset of fungus.

Whilst I ponder what to do about it I've sat it under a desk lamp which has a UV bulb fitted.

regards
Bernard

Vivitar made some excellent lenses. The Close Focus variants of the 24mm and 28mm focal are examples. Some of the non-CF lenses too, so long as they were not made past the mid-eighties.

Hope my page helps.

Having left my lens under the UV lamp for the best part of a week I was discussing it with a neighbour who works in the 'tanning' trade (suntanning - not leather making).

He tells me that the lamp I was using is known as a 'blacklight blue' and emits only a very small amount of UV in the near optical range. This wavelenght does absolutely nothing to fungii and I would need much shorter wavelengths to even get close and then there would be potential hazards to sight.

He has offered to give it a 'zap' in a sunbed to see if that does anything.

Hey ho
regards
Bernard

I'm not sure about fungi, but there's an Ikea lamp that
emits enough UV to kill off the yellowing in old lenses.

The lamp is also popular for lighting macros even though it
isn't a daylight LED.

http://www.youtube.com/watch?v=3CAaSgK6WsE

also see...

http://www.dpreview.com/forums/thread/3019506
'

As he said - it's on the internet so it must be true.

This is my lamp :-




And after 5 days it hasn't made one iota of difference.

Doesn't glass impede UV (?Rhetorical) - so anything on the inside surface is protected by the glass.

regards
Bernard

It's possible that a dental curing light of the original variety (UV as opposed to visible light), but they were not good for eyes so should be used with the appropriate glasses.

I think that a tech would disassemble the lens to get to the offending piece of glass. I also recall something about chemical baths. If the lens is worth saving I would have a professional deal with it.

The UV light should be able to kill the fungus but it won't remove the growth that's already there. If it's very faint then I'd say it's not worth taking the lens apart to clean it, as it won't have much effect on IQ and will be expensive to do.

No use according to this....... link

"1) UV bulbs (black lights) use woods glass, which is terrible for UVA/UVB transmission. It's a very inefficient design and hardly releases any actual UV."

If you do strip the lens down, be very careful not to lose the
aperture ring ball bearing, they fall out of Vivitars very
easily also take careful notes about what bits go where
-

The following pic is a closeup of what I can see when holding the lens at a slight angle to incident light - not the best (photographically speaking) but it does show the 'spider web'




It's off to the tanning salon at the end of the week - I'll report back later.

regards
Bernard