70 ltd busted


Link Posted 19/07/2012 - 09:09
My 70 Ltd no longer exposes correctly at f22 and I suspect that the aperture control is in some way wrong as when you flick it with your finger (off camera) it's sluggish to move unlike my other lenses. My guess is that it doesn't stop down fast enough and hence over exposes.

I cleaned the contacts but working the lever by hand suggests it's not as smooth as it should be.

Anyway it needs a repair - who do I go to? There's Johnsons but I'd rather deal locally if I could - I am based in Worcestershire.

All advice appreciated.


You can see some of my shots at my Flickr account.


Link Posted 19/07/2012 - 09:18
Johnsons, Asahi Photo or Harrow Technical all specialise in Pentax and will be able to clean the diaphragm on your lens.

It will mean packaging up and sending the lens, but it may well be cheaper to do that than travelling somewhere and parking.

It's a simple job that shouldn't take very long to do.
Best regards, John


Link Posted 19/07/2012 - 09:21
Interestingly Asahi declined to do it and recommended Johnsons. You think it's sticky blades then?

You can see some of my shots at my Flickr account.


Link Posted 19/07/2012 - 09:32
When my 18-135 lens was doing something similar they replaced a motor and a PCB (under warranty). I thought at first that it was only doing it at the 135mm end but the problem became more and more obvious the more I used the lens.
K5 + 18-135mm kit lens


Link Posted 19/07/2012 - 09:36
No motors here prime only and a lovely one too. I did wonder if it was a PCB that was failing as now I think harder it wasn't always at f22 but a good flicking seems to ease the problem.

You can see some of my shots at my Flickr account.


Link Posted 19/07/2012 - 09:42
Yes, it sounds like sticky diaphragm blades. Unless the engineers find it's something else.

It's worth repairing as it's a fine and expensive lens. Why not join PU Plus and go to JPS, taking advantage of the 20% discount?
Best regards, John


Link Posted 19/07/2012 - 09:44
10 quid to save 20 if their estimate is correct must be good I suppose.

You can see some of my shots at my Flickr account.


Link Posted 19/07/2012 - 10:46
I use a chap called Alan Marlow, I can let you have his email address when I get home if you wish. He recently stripped and cleaned my MkI Sigma 70-200mm for me as I am about to put it up for sale.

Charged me £40 incl return postage which I thought was pretty reasonable. I am sending my F* 300mm next.
. My Flickr


Link Posted 19/07/2012 - 10:49
Yes please Mike

You can see some of my shots at my Flickr account.


Link Posted 19/07/2012 - 11:47
+ 2 Mike please

K5's (2)both gripped, K10d gripped, Pentax 28-90 f3.5, Sigma 18-250mm, Sigma 150-500mm. Sigma 105mm f/2.8 EX DG Macro, Sigma 10-20 f.4-5.6.EX DC, Hoya 135 f2.8, Take on 28mm f2.8 Pentax AF360 flash, 2 fill in slaves. 30 metre remote release, Rt angle viewfinder, Giotto NOT 3261B Tripod with Manfrotto 808Rd4 ball head, Manfroto 4861RC2 monopoly, shoulder stock, various filters etc, Panasonic SET HBS HD Video cam, Tamrac Explorer 8x backpack and a sore back.....
Photography is an index for measuring futility and pride.......


http://s743.photobucket.com/home/pg20_photos/index http://www.flickr.com/photos/pg20


Link Posted 19/07/2012 - 12:56
+3 please Mike

No matter how many lenses I have owned - I have always needed just one more


Link Posted 19/07/2012 - 13:49
I've used Alan a few times for lens repairs although on older manual glass. He did a nice job of getting rid of the fungus on my S-M-C Takumar 135mm f/2.5 lens. His charges are reasonable and the turn-around pretty quick.

Kris Lockyear
It is an illusion that photos are made with the camera… they are made with the eye, heart and head. Henri Cartier-Bresson
Lots of film bodies, a couple of digital ones, too many lenses (mainly older glass) and a Horseman LE 5x4.

My website


Link Posted 19/07/2012 - 14:27
Am I correct in assuming this is him? link
Too Old To Die Young



Link Posted 19/07/2012 - 14:30
bforbes wrote:
Am I correct in assuming this is him? link

Yup, that's him
. My Flickr


Link Posted 19/07/2012 - 18:03
I don't need Alan's services quite yet, but I've bookmarked him since he's relatively local to me, and my ops supervisor lives in Shepperton too.

Sometimes, useful info such as this just "falls into one's lap".
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