[Vranx]

If I want to store an unused lens not attached to a camera, what is the best position for the aperture ring:

- wide open (largest aperture) like mounted on the body?
- fully closed (smallest aperture)?
- A position if available locked in or not?
- MF/AF clutch in MF position or AF?

Due to the fact that Pentax has mechanical aperture control with springs I would be curious whether it is better to have more or less tension on those springs to keep the alive for as long as possible...

Any advice or experience in this field?

Thanks in advance!

[Lowell Goudge]

I have never bothered about this.

Note many lenses may be defaulting to either stopped down

SMC-FA-J and DA lenses for example as they have no aperture ring.

Lenses with an A setting are either stopped down (A position) or at where ever the aperture ring leaves them

Non A lenses could be left anywhere.

Having said I never bothered about this, I do note that I have seen some vivitar (by kiron) lenses and kiron lenses with oil all over the blades when stored in the open position. I don';t know if this is related or not because I have the impression Kiron lenses from the late 70's and early 1980's are prone to this.

[fotaki]

Wow!! I think you've opened a can of worms here.

I have no technical based opinion on this but purely from the point of view of observing new lenses straight from the box, they all seem to arrive with the diaphram wide open. This would seem to suggest that lens manufacturers do have a preference.

[Lowell Goudge]

Wow!! I think you've opened a can of worms here.

I have no technical based opinion on this but purely from the point of view of observing new lenses straight from the box, they all seem to arrive with the diaphram wide open. This would seem to suggest that lens manufacturers do have a preference.

Note, not all.

see my comment above, the FA-J and DA lenses do not have an option, the aperture si stopped down when not on a body, as is any A lens when dismounted in the A position.

Additionally In my Tamron instruction guide that came with my XR Di 28-75F2.8 there are no storage instructions, and with my sigma APO 70-200F2.8 EX ther eis the following

Basic care and storage

- avoid shocks and exposure to extreme high or low temperature or to humidity
- for extended storage, choose a cool and dry place, preferrably with good ventilation. To avoid damaging the lens coating keep away from mothballs or naphthalene gas.
- do not use thinner, benzene, or other organic cleaniong agents to remove dirt or fingerprints from the lens elements. Clean using a soft moistened cloth or tissue.
- this lens is not waterproof. When you use thelens in the rain or near water, keep it from getting wet. It is often impractical to repair the internalmechanism, lens elements, and electric components damaged by water
-sudden temperature change may cause condensation or fog to appearon the surface of the lens. When entering a warm room from the cold ourdoors, it is advisable to keep the lens in the case until the temperature of the lens approaches room temperature.

Seems crystal clear to me, they simply don't care about aperture.

Note also, while we are discussing pentax lenses here, many other makers have apertures that close automatically and open with the activation lever, canon and olympus come to mind immediately

[fotaki]

Lowell Goudge.....I posted my reply before having the oportunity to read yours. As i said, mine was a non-tech opinion, Whatever...

[Vranx]

I do note that I have seen some vivitar (by kiron) lenses and kiron lenses with oil all over the blades when stored in the open position.

Hi Lowell: Do I understand correctly: storing the lenses with the aperture ring set to the largest (f 1:2 or 1:2.8) aperture caused the problem of the sticky blades?

Pentax Germany answered me today, they basically said (in surprisingly wrong German, sounded like translated by a computer from Vietnamese...) that it doesn't much matter, but if you want to be 'precise' keep the aperture ring wide open.

Hmmm...

[Lowell Goudge]

Hi Lowell: Do I understand correctly: storing the lenses with the aperture ring set to the largest (f 1:2 or 1:2.8) aperture caused the problem of the sticky blades?

Pentax Germany answered me today, they basically said (in surprisingly wrong German, sounded like translated by a computer from Vietnamese...) that it doesn't much matter, but if you want to be 'precise' keep the aperture ring wide open.

Hmmm...

No, not exactly. It is an observation that the normal storage of the lenses involved was wide open, however the lenses involved have a reputation for sicky blades anyway, but when you consider that if the lens is stopped down, any oil coming from the focusing helix grease will not necessairly hit the aperture (because the blades are largely between the lenses when stopped down, it is possible.

the real issue with sticky apertures is a grease that releases too much oil or that brakes down and turns to oil, and not the storage position of the aperture, however, it couldbe possible that for lenses which have a reputation for oil coming out of the focusing helix grease, storing the lens stopped down may prolong the time before the blades stick.

[alohadave]

No, not exactly. It is an observation that the normal storage of the lenses involved was wide open, however the lenses involved have a reputation for sicky blades anyway, but when you consider that if the lens is stopped down, any oil coming from the focusing helix grease will not necessairly hit the aperture (because the blades are largely between the lenses when stopped down, it is possible.

the real issue with sticky apertures is a grease that releases too much oil or that brakes down and turns to oil, and not the storage position of the aperture, however, it couldbe possible that for lenses which have a reputation for oil coming out of the focusing helix grease, storing the lens stopped down may prolong the time before the blades stick.

The way that the aperture assembly is constructed, once oil gets near the assembly, it's going to get everywhere, no matter what position the blades are stored in.

Oil on the blades should be an indication that the whole lens is due for a strip-down cleaning.

[stevebrot]

FWIW, I have a fair number of lenses (some quite old) and have owned some of them for almost 30 years. I have never paid any attention to the position of the aperture scale, have had no problems, and don't believe that it makes any difference.


Steve

[Adam]

It doesn't matter, since the stop-down lever is always wide-open on lenses with automatic diaphragms, and the aperture ring merely limits how far it'll go.