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Posted

I tried to mount my 500mm Hasselblad CF lens to my 503CX camera today and much to my surprise it would not register or click into place.. Yes, both the camera and the lens were  correctly cocked  and the red marks were aligned,.  The lens would rotate but would not  mount.    I tried other lenses on the camera and all mounted correctly.  I also tried the 500mm with another camera and no go, although it also  worked perfectly with other lenses. Can't imagine what the problem could be.  Please help. 

Posted

You may not be able to solve this easily: the huge 500mm lens suffers inordinately from the depressingly boilerplate answer to every single 'Hasselblad not working right" question. Lets all chant it together: "the Hasselblad system was marketed as a professional tool with the clear understanding/assumption it would be used daily and serviced every couple of months: not a problem during its heyday when every town had at least two skilled techs (and you didn't own a Hassy unless you were a working pro or wealthy amateur with the income to pay the upkeep)". For those of us using the system more casually and sporadically today, that "1963 Ferrari" ethos can be a headache and a half.

An unusually large percentage of 500mm teles are afflicted with shutter issues, which can in turn lead to the mount/dismount issue you're experiencing. The "gotcha" with the 500mm is its very limited purpose: even those who paid full price when new didn't need it as a daily driver lens. But that "occasional use" profile locks horns with the shutter mechanics, which are the same as in all the other Hasselblad lenses (use it or lose it: left sitting it will gum up and require a CLA service). This is complicated further by the 500mm uniquely long flange-to-shutter distance: the extra long cocking rod requires the lens be in perfect limber condition to function properly. If the shutter is dragging or the cocking spring has weakened, you may experience mount/dismount and cock/release snafus.

Due to these deeply buried mechanics, the 500mm is one of the most difficult lenses to find service for today. The old C version with Compur shutter is virtually impossible to get serviced now, which is why most used examples are DOA. Your CF Prontor version may still be repairable by either Hasselblad itself or a handful of long-term independent techs who still have the special tools. Curing this problem with a CLA is likely your only option, assuming you can locate a capable tech and feel you'll use the lens enough to offset the probable $400 repair fee.

Short of that, the only thing I can suggest is finding a secondary body that it will fully lock onto and then leave it permanently on that body. It should still be possible to find a relatively cheap 500c or 500EL body that might be able to lock on to your 500mm lens. Going thru eBay or web dealers might be a hit-or-miss proposition: better if you can drive to a dealer with the lens in tow and try out their second hand stock til one "clicks". If none click, either service the lens or get an adapter to use it as a super tele on a non-Hassy-V digital platform.

Good luck!

Posted

Fantastic: sometimes we get lucky! Hope it will continue on its merry way now that you've revived it.

I would still be extra careful with this lens: when these symptoms arise, they often reoccur without warning. My biggest concern would be the cocking spring regressing while the lens is being removed from the body: if this happens you'll suffer the ultimate in Hasselblad jams (shutter fired, mirror up, lens welded to the body, advance knob frozen), the kind that is not easily remedied by the "screwdriver down the throat" trick.

To avoid this, remove or attach the lens with a quick smooth movement (as quickly as possible, given the size and awkwardness of the barrel). Any hesitation or slowness can trigger a sync conflict between the body and lens mechanics. I've been burned by that several times with a particularly eccentric 250mm Sonnar: recovering from it requires a partial disassembly of the cocking geartrain behind the body lens mount, to release the spring tension on the body key and allow the lens to dismount. Not something I recommend as DIY unless you're stuck in the field far from any technicians.

  • 1 month later...
Posted

If as Orsetto suggested, the cocking mechanism is at fault, it is not difficult to remove the screws securing the mount to the lens, withdraw the tube and clean/lube the cocking spring and pawl. For those of us who have had these lenses apart, they are quite honestly the absolute most fragile of all Hasselblad lenses.  Look at where the shutter is located, then measure the length of the lens barrel.  That barrel is held on to the shutter with the same number of screws in the same aluminum casting as an 80 mm lens!  What were they thinking?.  You don't need to be a mechanical engineer to figure out the load on those screws is incredibly high.  Bump your lens/lens hood into anything more rigid than a feather and you stress those poor little screws and their threads, causing the entire lens assembly to wobble until properly addressed during service.  .   

  • 7 months later...
Posted

yes, a quandary, both are right, attach firmly, so the 'tripper' hasn't time to catch and fire the shutter, I also have had the same 'gotya' with the v system 55mm ext. tube, the thing is it LOOKS cocked, but that can be 180deg out, hence why it won't fire; also lookup a YouTube channel called Annie7B she goes through the partial disassembly process, its NOT that hard, just a tin cover, and prying the gear drive off mesh, simple, but just have a good set of jewellers screwdrivers and a long tweezer. reinforcing the tips, USE it, or lose it: leaf shutter springs need workouts at the gym if not using for a while, mount, fire throughout the shutter speed range to limber up the spring, to keep it supple, Mamiya RB\RZ manuals actually state this, and DONT store them COCKED, fire it, to save the springs, yes, if you think somethings off, get it CLA at a shop asap, a clean and oil\grease at ~$20-50 is better than a jammed shutter.

one other cause for the mounting problem is the age of it, if used well, and hard the mounting bayonets may have worn [or may have grit inside it] and not allow the parts to mate properly, the tripper has a crescent shaped shield around most of it, it may be obstructing mating up as the parts are high tolerance things so any 'wiggle' in it may stop things going smoothly. take it easy, like the camera techs with cinema cameras do, line-up, present squarely, push until home, and turn briskly, but not too fast... click, done! good luck, and may you enjoy the photos you get out of it.

Posted (edited)
4 hours ago, andyvan said:

[...] Mamiya RB\RZ manuals actually state this, and DONT store them COCKED, fire it, to save the springs, [...]

"Fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. Over time, such cyclic stresses can cause a spring to crack and ultimately fail, even if the stresses are well below the material's ultimate tensile strength."

https://www.alcomex.com/principles-of-spring-design-navigating-stress-strain-and-fatigue-for-enhanced-durability/

And quite a few other sources. Spring releasing, intending to save strings actually does the opposite: put them through extra, unproductive cycles, shortening spring life. So DON'T release spring tension. Store them COCKED.

 

Edited by q.g._de_bakker
Posted
On 9/26/2024 at 3:48 PM, q.g._de_bakker said:

"Fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. Over time, such cyclic stresses can cause a spring to crack and ultimately fail, even if the stresses are well below the material's ultimate tensile strength."

https://www.alcomex.com/principles-of-spring-design-navigating-stress-strain-and-fatigue-for-enhanced-durability/

And quite a few other sources. Spring releasing, intending to save strings actually does the opposite: put them through extra, unproductive cycles, shortening spring life. So DON'T release spring tension. Store them COCKED.

 

"Spring releasing, intending to save strings actually does the opposite: put them through extra, unproductive cycles, shortening spring life."

I'm not convinced that these extra releases make a significant difference, especially as there are recommendations to exercise the shutter (and spring) regularly - the few times you release the spring for storage is minimal.

However, storing a released lens makes it much likelier that you will try to mount it on the body that way, which will jam the lens to the body, and removing that jam requires a certain force that puts some real wear on the synchronization pins. This will shorten the working life of the lens more than that spring cycle.

I also recommend storing your Hasselblad lenses cocked.

"Manfred, there is a design problem with that camera...every time you drop it that pin breaks"
Posted
On 9/28/2024 at 5:53 AM, tom_chow said:

"Spring releasing, intending to save strings actually does the opposite: put them through extra, unproductive cycles, shortening spring life."

I'm not convinced that these extra releases make a significant difference, especially as there are recommendations to exercise the shutter (and spring) regularly - the few times you release the spring for storage is minimal.

However, storing a released lens makes it much likelier that you will try to mount it on the body that way, which will jam the lens to the body, and removing that jam requires a certain force that puts some real wear on the synchronization pins. This will shorten the working life of the lens more than that spring cycle.

I also recommend storing your Hasselblad lenses cocked.

I agree that the effect will be small (though springs can and do fail, due to nothing else).

Just putting across the point that what causes wear in spring is not tension, but tension-release cycles, and that "DONT store them COCKED, fire it, to save the springs" is the opposite of true.

 

Your advice to keep springs tensioned for the reasons you mention is good.

 

 

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