Should I keep shutter cocked ?

[michael_bisset1]

<p>I have a 1996 Hasselblad 503CW with a CF 2.8/80mm lens. The main spring on the shutter has just had to be replaced following a major failure.<br>

My question is whether I should store the camera between use with the shutter cocked. I'm sure I have read some where that after taking a shot you should wind on the film and cock the shutter ready for the next time the camera is used. As there may sometimes be many weeks or even months between use I just wonder if keeping the shutter cocked for long periods may have been a contributing factor in the failure of the shutter spring. As far as I am aware this was the first failure in 15 years.<br>

Thanks for your help</p>

[michaelging]

<p>You are going to get a lot of different opinions on this, and many viewpoints. Mine is, that a spring should always be un-tensioned when you are not going to be using it for a long period of time. I have also been told that when using roll film , that you get a sharper image when you advance the roll just before exposure. YMMD</p>

[q.g._de_bakker]

Here's one different 'opinion'.<br>Metal springs fatigue, not due to being kept under tension, but by cycling them from being under tension to not being under tension, and back again.<br>So releasing the shutter to relieve tension makes the springs age faster. Keeping the shutter cocked, springs under tension, does nothing.<br>So leave the shutter cocked.

[ian_rose]

<p>As a mechinical engineer I can see both sides of the arugment.<br>

1. as QG states as most springs are rated for # of deflections.<br>

2. If a spring is left under load for a extended period of time it can become deformed and loose some of the ability to return to it's normal. this is the same whether it is compression or extension.<br>

The Best example I have seen is if you place a old car spring next to a new one the pair I saw was from a 4 year old car and the old spring was about 1"shorter than the new spring.(this is with coil springs)<br>

So in my mind there is no correct awnser for this question as both are both are just as bad as the other</p>

<p>Ian R</p>

[Rob F.]

<p>I think a typical shutter spring is not tensioned 100% when cocked; and not relaxed to 0% when released. In the case of a Leica M shutter, the spring is 60% tensioned when wound, and 40% when relaxed. Perhaps the Hasselblad shutter is similar. Assuming the spring is tensioned significantly less than 100% when wound, then it is being kept well within its elastic limit; in which case I don't see why any fatigue should be caused by keeping it wound.</p>

<p>But: with that said, I don't know that there isn't some fatigue; I just don't know why there would be. There is an issue with the springs on the older C lenses getting weak over time. They were replaced with better ones in the CF and later lenses. David Odess replaced the springs in my old 80mm C lens when he overhauled it.</p>

<p>This might be a good time for David to come into the discussion . . .</p>

[leighb]

<p>Shutter springs are always under tension, whether cocked or released. This is true for leaf shutters and focal plane shutters.</p>

<p>The difference in tension between the two conditions is small, just a few percent depending on the shutter design.</p>

<p>All dismounted Hasselblad V-series lenses have the shutter cocked. That's a requirement of the system design.<br /> It's not possible to remove a 500-series lens from the camera body unless the shutter is cocked.</p>

<p>- Leigh</p>

[jim_momary]

<p>Another manufacturer has a different "corporate" opinion -<br>

'"Mamiya recommends to store the lenses with shutters released when they are not used for a long time." (from camerapedia.wiki.com)<br>

... last page of the RZ67 Pro II manual ("Care of the Camera" section):<br>

"When not used for a long period of time, remove the battery and<br>

film from the camera and keep mirror and shutters in uncocked<br>

state..."<br>

Back in 2006, I emailed Mamiya directly and asked this question of them. The 'stock" answer I got back echoed the above. It might also have to do with moving a mirror away from a foam bumper that may get gooey ?<br>

Beyond this, it probably really isn't critical one way or the other as others have stated.<br>

Jim</p>

[michaelging]

<p>My RZ67 had a electronic shutter, if I remember it right. I am sure there is a spring also, but would not be a critical as a mechanical shutter. </p>

[sfcole]

<p>One annoying thing about the 500c/m is that it has no shutter release lock, and I'm always accidentally firing blanks when putting it away (I use a 35mm+zoom-type tamrac into which it fits well). So there's that...</p>

[leighb]

<p>Scott,</p>

<p>If you have a rear cap on the lens, as you should, it won't fire when you put it away.</p>

<p>- Leigh</p>

 

[brett_rogers]

<p>Scott, the 500C/M does have a shutter release lock. It is called a film magazine, with a dark slide...</p>

[russ_britt3]

<p>I went to a class taught by Ernst Wilde, the Hasselblad technical advisor, in 1980. (ps he wrote the book) he got very animated when asked this question in class......he said "all Hasselblad optics were designed to always remain cocked!"<br /><br />Think about this, the so called (jamed Hasselblad) can only happen when an un-cocked lens is removed or put on a body that's cocked. So if optics remain cocked you will not lock your camera. <br /><br />But I'm sure the experts here will dispute what Hasselblad has designed itself into its very optics.....<br>

They do need to be exercised, but then re-cocked when stored, but un-cock them and risk a jamed camera if you like, after all its yours.<br>

The same argument comes up on 1911 pistols, they were designed by John Moses Browning to be safely carried cocked and locked, but some experts don't carry that way?<br /><br /><br>

They will certainly always last longer when used, not just stored....That's just my opinion. <br />Not worth anything.</p>

[michael_bisset1]

<p>Thanks for all your help. For the moment I plan to keep the shutter cocked.</p>

[q.g._de_bakker]

Hasselblad designed the cameras and the way they link up and synchronize with the mechanism inside the lenses, not with the life span of springs in mind, but because that's the way they could link and synchronize camera and lenses.<br>Any talk about "designed to always remained cocked" is not wrong, unless you interpret it as something even remotely meant to express an intention to keep springs alive longer. That will probably have been so far at the back of their minds that it's safe to say they never gave it a thought.<br>So yes, Russ, it must be disputed: Hasselblad did indeed not design anything like a spring saving functionality into their lenses.<br><br>The particular way Hasselblad cameras and lenses link up demand that, for easy operation, you keep the shutters in the lens and cameras ready, i.e. cocked. Else you can't remove or attach a lens, nor see anything through the viewfinder. So keep everything cocked = be ready to actually use your camera. (Something that is true for other cameras too, by the way).<br>Or, as Wildi put it: Hasselblads are designed to be kept cocked. You have to, if you want to use them.<br><br>Again, spring life is not influenced by the strain the spring is kept under. It's hugely influenced, however, by the number of changes in tension. So release the tension hoping (falsely) to prolong the life of the springs, and you will in fact achieve the exact opposite: shorten their life span.<br>(Using springs will not make them last longer, Russ. It will fatigue them until they finally give in and snap.)<br><br>What keeping springs under tension also does, is keep the various parts of mechanism tight, making them more resistant to shake.

[russ_britt3]

<p>Exercising the shutters to prolong their life, is not about the springs, but to keep moving parts moving. <br />I have always found that used (professional used) cameras seem to work better than, (saved and looked at) cameras. <br />Use is good for them......nothing last forever that has ever been made by men.</p>

<p>But tell me which of the digital cameras will be operational 60 years from now?<br>

<br />Mechanical Hasselblad are built amazing well I think. <br />Not so sure about the newer electronic ones.....</p>

[rodeo_joe1]

<p>Just to clarify a point about so-called "electronic" shutters. Most of these are basically still mechanical shutters using springs and cogs for their motive power. The electronic bit is simply used to time the exposure.</p>

<p>A traditional shutter uses a gear-train (similar to a watch mechanism) to time the delay between opening and closure. The shutter blinds or leaves are held open by a mechanical pin until the timing train winds down and releases it.</p>

<p>With an electronically-timed shutter the timing train is replaced by an electronic circuit and the restraining pin is replaced with a solenoid that actuates after the exposure time has elapsed, and that's about the only difference. The main tensioning and power for the shutter still comes from a mainspring. So it makes no real difference whether you have a purely mechanical shutter or a hybrid "electronic" one. They both use a spring and both offer the same dilemma of "to tension or not to tension?" </p>

<p>Personally I would be swayed by the argument that the film can take a kink if left tensioned across the rollers for any length of time. That seems far more relevant than trying to extend the life of a spring.</p>

[q.g._de_bakker]

Exercising shutters (and other mechanical things) is not to keep the parts in good shape, Russ (they will inevitably wear a bit every time you move them, everytime you exercise them), but to keep the lubrication that is put on them to protect them against such wear from turning into a glue that will make them stop moving the way they should.<br><br>You do shorten a spring's lifespan by releasing the tension (and subsequent retensioning). Doing so when it is not needed, even because you would hope it would prolong their lifespan, is the worse of the two options this thread is about.

[david_olsen5]

<p> I have a Rollei 35S ( Sonnar ) that has to have the film advanced and shutter cocked in order to retract the lens. It is probably 40 years old. Don't know if it is original shutter and spring as I bought it used last year. Seems to work fine though.</p>

<p>DaveO</p>

[ws_ho]

<p>Should 903SWC be shutter crocked or released for long storing time? Thanks.</p>

[q.g._de_bakker]

Cocked.