Leica M lubricants vs Nikon F2

[SyPat]

(...) In the absence of equipment able to measure travel time I would start off with settings that see an even, accurate full gate exposure time (Ie 1/60, you are eliminating slit maladjustments from the equation this way) and that should get you in the ballpark hopefully. Then check faster and slower speeds and fine tune *consistent* exposure across the gate at 1/500 & 1/1000, before addressing slit adjustment if needed. Not as precise as Eg a Kyoritsu tester but if you have a bit of experience ought to give a very usable shutter with reasonable times. Not having worked on F/F2 yet can't be more specific, sorry.

I have a good shutter tester, but not able to measure travel time for each curtain.

I have three F2, I checked them all and all were too slow from 1/250 to 1/2000. I restored the correct situation playing with the excentrics and slightly reducing the tension of the second curtain. The 1/2000 remains not very reliable (not a problem for me), but the other speeds are very accurate from side to side.

 

[Rob-F]

All cameras should be stored UN-cocked. Cocked increases tension on the shutter and cause the shutter speeds to alter.

There's really no scientific reason for this. Yes, it is intuitively appealing; but it's wrong. The assumption here is that being under tension hastens the wear, or aging of the spring. It doesn't. Wear, aging, or metal fatigue occurs during the flexing of a metal part such as a spring. There is no fatigue when the part is not being flexed. So unnecessary cocking and firing of shutters will hasten the need for repair; storing with the shutter cocked, won't.

Regardless how you store your cameras, the shutter drum springs are tensioned above 70% at rest and never reach a fully tensioned and bound 100%, so it doesn't really matter. Just use your cameras, don't abuse them, and they will all outlive you.

Phil Forrest

That's all true. Leica shutters are similar, being tensioned (as I have read in our pages, here) at 40% when not tensioned, and 60% tensioned. That maximum figure when tensioned, matters:

Hooke's law states: F=kx, where F is the force applied to the spring, k is a constant related to the characteristics of the metal, and x is the distance by which the spring is deflected when being tensioned. Hooke's law specified that the relationship between F (force) and deflection (x) is linear, as long as the distance x is not large compared to the amount that would deform the metal, known as the elastic limit. So we can see that the engineers were being conservative by choosing a maximum figure of 60% or 70%. This is a long way of saying that Phil Forrest is right.

 

[SyPat]

There's really no scientific reason for this. Yes, it is intuitively appealing; but it's wrong. The assumption here is that being under tension hastens the wear, or aging of the spring. It doesn't. Wear, aging, or metal fatigue occurs during the flexing of a metal part such as a spring.

True in theory, but not in practice. You neglect one thing: metal alloy. Not all metals react the same way to pressions/torsions, etc.

As far as I know, the composition of springs in cameras in unknown, so we can't predict how they behave.

 

[Phil_F_NM]

Nikonos III shutters NEED to be stored in the cocked position in order to keep the lever from breaking or possibly damaging the winding mechanism and shutter escapement. In fact, Nikon may have made this quite heavy winder lever out of plastic with the forethought that if the one part was going to break, it would be this one, not the more delicate internals.
A purpose built underwater camera is not one that is typically used daily, so long storage times are expected and this was built in to the design. So here, almost 50 years after the first Nikonos III (I'm not even talking about the previous Nikonos or the Calypso) most of those that have not been flooded or had the frame bent, are still working fine.
If you want to talk spring tension and wear, just look at firearms. Many of them are stored cocked, even if it may be against recommendations (for safety's sake and operational longevity) yet still they keep operating, often in extraordinarily bad conditions and in regular extremes of weather.

Phil Forrest

 

[Godfrey]

In 50+ years of using all kinds of cameras, I've never seen much evidence that showed it mattered one way or the other as to whether the shutter was left cocked or uncocked. Some cameras/lens assemblies cannot be stored uncocked, some have to be.

I just use 'em all, get used to their various quirks, and get on with making pictures. Getting too concerned that the shutter is not absolutely, perfectly calibrated and accurate is a fine way to ruin the joy.

Most of my cameras do well enough to make a good photograph, consistently. That's all that matters.

G

 

[davidnewtonguitars]

Surely depends on the camera brand and type of mechanism. Leica shutter springs, and most focal plane shutters, are always tensioned, just a little more when they are advanced.

 

[F456]

Regardless how you store your cameras, the shutter drum springs are tensioned above 70% at rest and never reach a fully tensioned and bound 100%, so it doesn't really matter. Just use your cameras, don't abuse them, and they will all outlive you.

Phil Forrest

Good advice, Phil, about just using them. I find I start worrying about these things only when I haven't had a chance to go out and take photographs for a while. Once in action the potential problems fall back to minor proportions!

Tom