Hello folks,

I've got an age old question, but due to not knowing the answer, I have to pose it: How shall I store my lens's shutter to maximise its predicted lifetime (as far as the springs are concerned)?

I have the Rodenstock Optar 4.5/135 in a Graflex 1000 2A shutter (the standard combination of the Graflex 45 Super Speed Graphic featuring a 1/1000 sec time), thus there are 1/1000-1/2, B, and 0 (a special setting which is to be used for depth-of-field preview).

Cheers,

-- David Haardt (david@haardt.net), August 15, 2001

Answers

David, it's already made it 25 years past it's predicted lifetime. I would think a zip-loc baggie with a desicant pack would be hard to beat. Spring steels are going to age and change no matter what you do. Better to spend the $85. for a shutter speed tester and find out where it's at and go with it.

-- Jim Galli (jimgalli@sierra.net), August 15, 2001.

Springs used within their design elastic limits do not "know" whether they are stretched, relaxed or compressed. It makes no difference. So, the best option is one in which the iris and shutter blades are opened so as to avoid accidental mechanical damage.

A stopped car engine, for example has some of its valve springs compressed and some relaxed. Even if stored for an extended period there will be no difference to the springs which will still all be alike.

SKG

-- Steve Grimes (skgrimes@skgrimes.com), August 15, 2001.

Dear Jim,

Well, I did already shoot my whole Scotland trip with it because I received it directly before I went there ;-)

Here a Scotland shot: http://home.pages.at/haardt/lfgallery/duart.htm

I meant the predicted lifetime from now on - as it is obviously working quite well at all speeds (no visible problems with exposure) I would suppose that technically, its predicted lifetime from now on will be >0 ;-)

Thank you, Mr Grimes. That was exactly what I wanted to know ;-)

Cheers,

-- David Haardt (david@haardt.net), August 15, 2001.

Hi David, got nosey and looked at the rest of the Scotland pics! Very nice! This was my favorite, http://home.pages.at/haardt/lfgallery/water.jpg and the selective focus of the Leica on the couch is also very pretty. I hope my little poke at humor didn't rub you the wrong way. One of these days I'll learn to keep my mouth shut. jimgalli@sierra.net

-- Jim Galli (jimgalli@sierra.net), August 15, 2001.

A slight correction to Steve Grimes point about springs. While a shutter spring may be within its 'elastic' limit for both the cocked and un-cocked shutter, it certainly does 'know' whether it is stretched or not. In the stretched case, there is more elastic stress in the spring (that is spring energy), proportional to the square of the difference in the displacements from a fully relaxed spring.

More to the point, what Steve is getting at is that within this elastic regime, the 'deformation' of the spring is not significantly different when the shutter is cocked or not. 'Deformation' is a technical term that describes what happens to the metal on a microscopic scale that results in the 'aging' of a spring.

-- Richard Ross (ross@hrl.com), August 15, 2001.

Another slight correction to Mr. Grimes post,
Automotive valve springs do fail due to being stored in a compressed state.
As do the suspension springs on an automobile.

When a fellow does a valve job on an automotive cylinder head , he uses a valve spring tester to determine psi and spring length.

When a fellow does a wheel alignment on an automobile, he uses a tape measure to check "ride height" and if ride height is not within specs the springs must be replaced.

However, I must note that it is more a result of heat that causes this , rather than actuall compresion alone.

So while I am not really offering a answer to the question, I can say dont heat your shutters to 800 degrees and then store them compressed, as in the case of automotive valve springs.They will fail.

-- Rusty (rusty@apex2000.net), August 16, 2001.

Brand new, factory fresh, lenses from Rodenstock are shipped in a standard unsealed plastic bag with a dseeicant pouch in the bag.

The Copal shutter is uncocked and set to "T" and the aperture setting is wide open.

Neither the factory, the distributor or the retailer really knows how long a new lens will remain in stock at the factory, the distributor or the dealer prior to it reaching a user.

So your lens should probably be stored the same way.

-- Bob Salomon (bob@hpmarketingcorp.com), August 16, 2001.