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05-07-2011, 11:15 AM   #1
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"slack" lens?

Before starting, I have to say that I'm new to the more 'serious' photographic equipment - serious may be an exaggeration - I've recently acquired an ME Super in excellent cosmetic condition (only bought from e-bay for it's low price and the useful range of the 28-80 zoom lens mounted on it - bought more for the lens than the body) after receiving a tatty old black MX as a Christmas present (which I was very pleased to get)

I have a small assortment of M lenses in various conditions (50mm 1.7, 135mm f3.5, 40mm f2.8, 70 - 200mm f4.5) All perfectly usable and all 'feel' very similar - weighty without feeling heavy, all having a smooth, damped operation of focus (and zoom) giving a little resistance when used - also with a positive 'clicky' aperture ring.

The A series short zoom 28-80 lens I got with the ME Super feels very different. While it is in very good cosmetic condition with nice clean optics, adjusting both focus and zoom is a very 'loose' affair - no resistance whatsoever and feels terrible to use because of it.

Is this normal for A series lenses or is there something wrong? If this isn't normal for this type of lens, is there anything I could do to adjust it?

I'd appreciate any help or comments you can give.

Many thanks,

Gary.

05-07-2011, 11:27 AM   #2
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No, that's not normal- it's a sign that the lens has seen extensive use.

Does your A lens otherwise look like an F lens? Toward the end of the A series Pentax did produce a few plasticky MF lenses which otherwise look like AF lenses- I'm not sure how they handle, but maybe they're more loose than they should be.

See our lens database at Pentax Reviews - Pentax Lens Reviews & Pentax Lens Database for more details
05-07-2011, 11:43 AM   #3
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Thanks for such a quick response Adam.

The lens looks just like the one shown in the site's database



Any idea if there's anything that can be done by an amateur to adjust the action? (although I'm much more familiar with socket sets and hammers than tiny little toy screwdrivers )
05-07-2011, 11:56 AM   #4
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Just because the lens is 'loose' doesn't mean it won't work. Give it shot. You have a good collection of lenses that will work a new Pentax DSLR as well as your ME.

05-07-2011, 11:57 AM   #5
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Hi, Gary,
I have 2 of those, Takamur A versions, a well used one and a better one.
Even the better one is quite loose as you describe.
They feel like the settings would change if you gave a shake, but they don't
I've seen it mentioned on the forum before.
05-07-2011, 02:19 PM   #6
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QuoteOriginally posted by wombat2go Quote
Hi, Gary,
I have 2 of those, Takamur A versions, a well used one and a better one.
Even the better one is quite loose as you describe.
They feel like the settings would change if you gave a shake, but they don't
I've seen it mentioned on the forum before.
Thanks for replying Wombat - that's exactly the sensation it gives when in use. I think it's absolutely functional, but I have no confidence in it (which doesn't really matter, as I'm only learning), but more to the point, it just doesn't feel 'nice' to use.

The reason I got interested in film photography is a bit long-winded. It was due to my daughter requiring a manual film camera for her college course. Me and Mrs. Snail were out and about in November when we stumbled across a tatty looking old MX amongst similarly aged (and many more modern) Pentax, Nikon, Canon, Olympus etc. 35mm SLRs. A few cameras were man-handled and I kept going back to the MX - the feel of the controls and the sound of the shutter was just 'right'.

£79 (about 130 USD?) was exchanged for the MX body with a 40mm f2.8 lens and six months warranty, which I think was a reasonably good deal. How exactly it ended up being my Christmas gift still confuses me - my daughter got a more modern P30 with an A50 F2 lens and a Vivitar series 1 zoom from Santa! (Also a nice body to use)


QuoteOriginally posted by gp1806 Quote
Just because the lens is 'loose' doesn't mean it won't work. Give it shot. . . . . .
You'll be glad to know that it's happily mounted on the ME Super at the moment (I'm only on the second roll, and I've yet to get the first one developed due to working weekends) and it is definitely usable, covering a nice range of focal lengths - I only clicked the "buy it now" for this lens really (£35 UK - bit on the steep side perhaps, but it came with a free camera )


QuoteOriginally posted by gp1806 Quote
. . . . You have a good collection of lenses that will work a new Pentax DSLR as well as your ME.
You, gp1806, are a bad influence . . . . . . but if I'm honest, the thought had occurred to me. It won't happen any time soon - I'm expecting grandchild number 1 in September, we'll have to end up helping our daughter out . . . which will be a pleasure - 35mm film will happily record the young one's development (as well as the Canon DSLR - sorry Pentaxians!)
05-07-2011, 05:12 PM   #7
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Ah, yeah, that'd appear to be one of those that's not a true 'Pentax-A' zoom, rather of the "Takumar A' breed: the zooms of which are not up to Pentax standards (I have the 70-200 like that, and while it's OK, (As opposed to the one like yours I saw in a pawnshop sometime recently: that lens was in a terrible way,) the focus/zoom ring on mine has about *zero* damping: a little problematic for my arthritis, to say the least.



But nearly every lens is good for *something,* and it's already in hand, so maybe see what it can do. (I really like my 'Tak-Bayonet' 135, actually. That lens is more of an M lens without SMC coating, though it gave the Pentax crowd fits when they used the revered 'Takumar' name for a budget line. The zoom I got on the rationale, 'Well, the 135 was OK, let's see what this does.' gives kind of nice pastels and probably would be good for soft focus. Otherwise no great shakes. )

As for adding some kind of damping, I haven't had mine apart, but I've thought I might try putting a little bit of self-adhesive foam grippy stuff on the inside of the focus ring (It's quite thin, maybe good enough for this, though something less prone to shed pieces would be better practice. A good quality light seal felt might do the trick. Maybe sneak a few tabs of it under the focusing ring, leaving enough sticking out to fold that part up onto the outside, so pieces don't get loose and end up in the works. I was thinking I might do that for a trial before looking for more-elegant solutions. )

Real Pentax-A-lenses, as in everything but the two not-real ones mentioned here, actually have my very favorite focusing rings in the whole world, at least the small primes, so don't be put off by that one.

Last edited by Ratmagiclady; 05-07-2011 at 05:22 PM.
05-08-2011, 01:40 AM   #8
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Thanks RML. It will get used for no other reason than because "it's there" and the 28 - 80 range will be useful (I think - I've no clue on composition really . . . . It'll come with practice)

I like your suggested solution - plonk something in there to give a bit of resistance. I've adopted this kind of approach on less sensitive items in the past - cars, kitchen doors, wireless radios have all been patched up.

It will however be months before I pluck up the courage to take it apart

I'll have a look in my daughter's camera bag to pinch the A50 F2 to play with. I really like the way the M lenses we have feel (even the skinny little focus ring on the 40mm pancake is nice, if a bit fiddly, to use - I may change my mind if I'm ever unfortunate enough to suffer with arthritis as you do)



It seems that these 28 - 80 lenses are a "pretend" A series lens of a lower quality design and inconsistent quality of manufacture and as a result - a bit more prone to, well, feeling a little "cheap" - it is what it is.

Fair comment?

Thanks to all who've offered opinion.

All the best,

Gary

05-08-2011, 07:23 AM   #9
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QuoteOriginally posted by garythesnail Quote
Before starting, I have to say that I'm new to the more 'serious' photographic equipment - serious may be an exaggeration - I've recently acquired an ME Super in excellent cosmetic condition (only bought from e-bay for it's low price and the useful range of the 28-80 zoom lens mounted on it - bought more for the lens than the body) after receiving a tatty old black MX as a Christmas present (which I was very pleased to get)

I have a small assortment of M lenses in various conditions (50mm 1.7, 135mm f3.5, 40mm f2.8, 70 - 200mm f4.5) All perfectly usable and all 'feel' very similar - weighty without feeling heavy, all having a smooth, damped operation of focus (and zoom) giving a little resistance when used - also with a positive 'clicky' aperture ring.

The A series short zoom 28-80 lens I got with the ME Super feels very different. While it is in very good cosmetic condition with nice clean optics, adjusting both focus and zoom is a very 'loose' affair - no resistance whatsoever and feels terrible to use because of it.

Is this normal for A series lenses or is there something wrong? If this isn't normal for this type of lens, is there anything I could do to adjust it?

I'd appreciate any help or comments you can give.

Many thanks,

Gary.
I had the Takumar-A version of that lens that was exactly the same way (and a couple others that were as well). Mechanically they are probably identical. Without taking it apart and re-damping it, there isn't a whole lot you can do about it other than just use it. It was always heavy enough to hold its position and the rotating zoom (rather than push pull type) kept in place pretty well even when tilted up or down. You probably already have the best solution, rig it and use it.

05-08-2011, 08:43 AM   #10
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Cheers Jeff - I'll keep using it until I finally develop a film to prove that it's working, not working or the evidence just confirms my complete lack of talent
05-08-2011, 01:31 PM   #11
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I have a Pentax ‘A’ 35-70 that acts the same way. The focus is ‘spot on’ and produces some quality pictures. I find myself double checking the focus before I press the shutter button. You might want to research Damping greases / Fluorocarbon Gel. I found a source for the grease, but very expensive at $90.00 US. That is more than the lens value and hard to justify spending that kind of money. Does anyone have an alternative?

Found product at Micro-Tools, this is a paragraph from the product info of the grease.
{Damping greases are specialty lubricants. They reduce wear and seal out dust and moisture like traditional greases, but their primary function is to control motion and noise in mechanical and electromechanical devices. For example, the "velvet feel," silent operation, and the fact that lenses don't coast are all the work of damping greases on the focusing threads of binoculars, zoom lenses, and other optical instruments.}

Micro-Tools Fluorocarbon Gel 868 Series Kit 10CC Syringes
05-08-2011, 07:02 PM - 1 Like   #12
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QuoteOriginally posted by Kaufeetime Quote
I have a Pentax ‘A’ 35-70 that acts the same way. The focus is ‘spot on’ and produces some quality pictures. I find myself double checking the focus before I press the shutter button. You might want to research Damping greases / Fluorocarbon Gel. I found a source for the grease, but very expensive at $90.00 US. That is more than the lens value and hard to justify spending that kind of money. Does anyone have an alternative?

Found product at Micro-Tools, this is a paragraph from the product info of the grease.
{Damping greases are specialty lubricants. They reduce wear and seal out dust and moisture like traditional greases, but their primary function is to control motion and noise in mechanical and electromechanical devices. For example, the "velvet feel," silent operation, and the fact that lenses don't coast are all the work of damping greases on the focusing threads of binoculars, zoom lenses, and other optical instruments.}

Micro-Tools Fluorocarbon Gel 868 Series Kit 10CC Syringes
I needed some grease for an underwater housing and the price was very high from the manufacturer. I bought some silicone grease at a plumbing supply house. This grease has interesting properties, non-toxic, water does not degrade it, maintains viscosity across a wide temperature range and does not dry out - or so it says on the label. I thought about this for a lens helicoid, but have not needed to dampen a lens. You might want to investigate this as an alternative.
05-09-2011, 06:17 AM - 1 Like   #13
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QuoteOriginally posted by gp1806 Quote
I needed some grease for an underwater housing and the price was very high from the manufacturer. I bought some silicone grease at a plumbing supply house. This grease has interesting properties, non-toxic, water does not degrade it, maintains viscosity across a wide temperature range and does not dry out - or so it says on the label. I thought about this for a lens helicoid, but have not needed to dampen a lens. You might want to investigate this as an alternative.
I do think you want to be careful with silicones around optics, at least random ones: (fogging, smears, any outgassing, etc.) I don't recall if I've heard anything specific there, though.

I tend to be pretty cautious about that sort of thing, though.
05-11-2011, 02:32 PM   #14
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Went for a spin in the car and took a few snaps this evening as the light was starting to fade. Took the MX / M 135 and the ME super with this zoom on. The 135 feels so silky smooth that it makes the zoom feel like pretty cheap and toy-like to use. Unfortunately, the equipment has more talent than the ham-fisted bloke using it

I think I'll persist with it until a ridiculously cheap turns up on e-bay with one o fthese attached to it. . . . . I think I've just understood the whole LBA thing all of a sudden
05-24-2011, 07:21 AM   #15
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I am new to the Pentax forum (first post), but not to Pentax. My first Pentax was a Spotmatic that I purchased new in the late 60s, followed by am ME Super and K1000. However, I recently moved from Canon (5D2) digital to Pentax (K5) so I could carry a smaller camera. I have a Cosmicar version of the 28-80mm that also falls sort of perfection.

I got the lens new in the mid 80s and it never has been a good performer. Problem is it is often soft. I find that if I tap the front of the lens it is then very sharp, but if I go to macro and back to normal it is soft again.

I assume that one of the inner elements is loose and the jar sends it to where it is suppose to be. Is there a way to tighten it in the correct location, or is it worn out? I like the lens because it fits the camera well.

Thanks,

Wayne
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