[Loop1]

I'm trying to figure out a few things with a new to me 67 with a 165mm LS lens. I don't see any explanation in the manual for the lens about the Auto vs. Manual switch. The only thing I can observe is that in manual it's stopping lens down like a DOF preview would do. Is that the extent of the functionality? Also, does that switch have any effect on the leaf shutter triggering? I have another thread going in troubleshooting where the LS is not firing reliably but so far not much insight into what might cause that.

[othar]

I don't know about that lens but with M42 lenses the M / A switch is needed to assure compatibility with cameras that can't operate the automatic aperture pin (on the back of the lens)
M: Aperture closes to whatever size is set on the aperture ring
A: Aperture is open but closes when the pin on the back of the lens is pushed in (either with the preview button or when triggering the shutter button)

I presume something similar will happen with your lens.

[stevebrot]

I don't see any explanation in the manual for the lens about the Auto vs. Manual switch.

I believe it is a feature of all Pentax 6x7 lenses. It's utility is to provide aperture stop-down when using bellows or other accessories (e.g. some mount adapters) where there is no coupling with the camera for auto aperture actuation.


Steve

[Loop1]

I believe it is a feature of all Pentax 6x7 lenses. It's utility is to provide aperture stop-down when using bellows or other accessories (e.g. some mount adapters) where there is no coupling with the camera for auto aperture actuation.


Steve

Ahh - that makes sense. Thanks

[gofour3]

From a 6x7 lens manual:

Phil.

[Silent Street]

There is no effect of the Auto/Manual switch to the operation of the 165LS in either FP (camera shutter) or LS mode. The Auto/Manual lever, as described by Phil's post, above, is for checking depth of field at the selected aperture and/or stop-down metering in the absence of a coupling to the camera body e.g. stop-down metering would be required if the (TTL) meter coupling chain on the camera should break.

The 165LS has some other restrictions you need to be aware of, the most critical being not use mirror lock-up when the lens is in LS mode as this will jam the leaf shutter.


I have seen several lenses, old and newer, that Auto/Manual lever has been subject to heavy use with the result that it does not engage, or the button itself has broken.


Difficulties in using the 165LS and the companion 90mm LS (which can be used with mirror lock-up in LS mode) are frequent, and reflect again the difficulty in finding old operating information from Pentax.

[Lord Lucan]

I don't see any explanation in the manual for the lens about the Auto vs. Manual switch. The only thing I can observe is that in manual it's stopping lens down like a DOF preview would do. Is that the extent of the functionality?

It is confusing because the meaning of the word "Auto" changes over the years. It often means what was the latest tech advance at the time.

When the 6x7 was introduced there were still cameras around that you switched the lens aperture to fully open for framing and focussing, and then you closed the aperture to the value you needed to take the photo. A camera/lens that did this itself was considered to be "automatic". Later the word "automatic" was moved on to mean a camera that set its own shutter speed according to its built-in meter. The 6x7 never did the latter of course, but the word "Auto" survived on its lenses. In later years this function would come to be called "stop-down".

I have been watching some YouTube videos on flash use. It is amusing that some presenters refer to the flash "Auto" mode (the mode where the unit's own photocell controls the light) as "Manual", because you are still required to set the lens aperture yourself (as opposed to TTL mode where you don't need to), despite this mode usually having the word "Auto" engraved on the selector switch.

[stevebrot]

It is confusing because the meaning of the word "Auto" changes over the years. It often means what was the latest tech advance at the time.

One of these days, I am going to write a short article on the subject. A pet peeve of mine is the use terms "manual" and "auto" without consideration of broader context. Lately, there is also the new term, "semi-auto" with reference to anything other than program exposure automation, when it already has an established meaning in the photographic context.

As for "Auto" flash meaning letting the flash manage its own output with a built-in light meter, the term is hardly archaic, though finding new product with the feature (still called "auto" mode) has become increasingly difficult. The Metz AF-1 still has that mode, while the last Pentax flash with the feature (AF540FGZ, AF360FGZ) were only retired about five years ago.

I could go on and on...


Steve

[tuco]

...
When the 6x7 was introduced there were still cameras around that you switched the lens aperture to fully open for framing and focussing, and then you closed the aperture to the value you needed to take the photo..

And there still were cameras like that being made long after the introduction of the Pentax 6x7; namely, large format view cameras with leaf shutter lenses. . But yeah I know what you mean.