[UncleVanya]

And now I know what this extra mark means above the aperture ring:

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[steephill]

I just had a closer look at my F zooms in brighter light and there is a small recessed green dot rather than a line. I had missed it before as the recess was filled with gunge. I got these lenses second hand and of course there were no user manuals included which might have explained how to use this feature. I have only found the generic F and FA series user manual online which doesn't include all those lenses.

[Lowell Goudge]

I have looked through a lot of the discussion and there are a few things missing or overlooked so far.

- Pentax DSLRs are all to some extent not really linear in their manual metering. This was really brought to head with the K10. If the camera does not know the true aperture of the lens the metering is off. In completely manual lens use, the most accurate camera metering is at F4-F5.6 because this is where most consumer lenses have their aperture range.
- due to the issue above, it becomes really important that for A series and later lenses, the lens report it’s true maximum aperture as you zoom or there will be metering errors, not only for normal shooting but also flash photography with P-TTL flash or with older flashes and auto flash mode
- For K mount lenses where there is no aperture feedback, you really need to know your lens, and how it behaves. On the individual bodies.

There were tons of threads on these issues 10-12 years ago.

These issues were not a problem in the film era or with TTL flash where the light was measured directly off the focusing plane for flash.

So it is really important that you know what your lens has and how it behaves. In a past thread someone asked if you test new lenses before using them. I responded no, but that’s a bit mis leading, I verify the exposure behaviour with the body(ies) I plan to use them with,

[pschlute]

- Pentax DSLRs are all to some extent not really linear in their manual metering. This was really brought to head with the K10.

You are correct up to a point. The K10D and following few releases were hopeless with older lenses for metering. This was due to the new optibright focus screens these cameras had. I know because I was one of the complainers.

I have used the K1 since 2016. No issue with any lens. Are folk still experiencing metering issues with their K1/K70/Kp/K5/K3 cameras. I do not hear it.

[Lowell Goudge]

You are correct up to a point. The K10D and following few releases were hopeless with older lenses for metering. This was due to the new optibright focus screens these cameras had. I know because I was one of the complainers.

I have used the K1 since 2016. No issue with any lens. Are folk still experiencing metering issues with their K1/K70/Kp/K5/K3 cameras. I do not hear it.

I stopped checking with the k 5. It was better but not perfect.



About +/-.75 stops, but better than -1/+2 stops of the K10

[mikesbike]

And now I know what this extra mark means above the aperture ring:

Yep, that was my conclusion right away years ago, with similar markings on a few other lenses. When I got this lens I was still shooting with my PZ-1P, and of course with the lens set to "A". But then I also got the ZX-5n for my compact model, so I had to go back to the aperture ring where the markings were once again useful.

It was upon first getting the PZ-1p my curiosity was stimulated about the new electronic control, and soon the general matter of variable-aperture lenses coming up in a magazine discussion. So I got to wondering, since this new camera could switch back and forth with full service either way, could I find out if the new electronic control could actually compensate for the aperture value change, preserving the set value when zooming such a lens, while the aperture ring of course could not. Everything being under electronic control, I reasoned, it should be able to do so, except if the lens is wide open and then zoomed to a longer FL, where it would be physically impossible to do so. My testing confirmed that the electronic control was indeed doing this, and I was delighted. The PZ-1p wowed me in so many ways, this being an important one. Now such an advantage has become the rule, but what a nice advancement made so long ago. The new Pentax Hyper System also blew my mind, and made full use of this factor. Especially in the M mode, where you could quickly take spot meter readings, select your preferred settings, and not worry about zooming this way or that.

---------- Post added 03-07-22 at 10:22 PM ----------

You are correct up to a point. The K10D and following few releases were hopeless with older lenses for metering. This was due to the new optibright focus screens these cameras had. I know because I was one of the complainers.

Yes, I found that out with camera models years back. I have heard of more recent models being more reliable, but it has been a long time since I have employed one of my old M lenses, since I have so many AF lenses of at least equal capability. With the old PZ-1P this is no issue at all, as it has full capability either electronically or with mechanical operation using the lens ring.

---------- Post added 03-07-22 at 10:31 PM ----------

then come back to it feeling more reasonable in the morning. It's almost like being married to the forum.

Ha ha ha ha...! That's a good one.