[MiguelATF]

I'm a long term Pentaxian, but a brand new K-5iis owner, and encountered a weird (to me) phenomenon I couldn't figure out when trying out my K-5iis along with one of the few K-mount lenses I currently have, the small FA 20-35mm zoom. With the aperture ring on its 'A' setting, in both the viewfinder and the LCD panel, it shows whatever aperture I've selected. But moving the aperture ring to any of its clickable aperture settings, the aperture Info disappears from both the viewfinder and the LCD.

I don't mind keeping the aperture ring in the 'A' position - and using the click-wheels to adjust aperture, in Av mode, if that's what's required - but I'm puzzled as to why the clickable aperture ring doesn't seem to be showing up.

Does some K5iis user more knowledgeable than I have an explanation or advice here?

THANKS in advance!

[luftfluss]

I'm a long term Pentaxian, but a brand new K-5iis owner, and encountered a weird (to me) phenomenon I couldn't figure out when trying out my K-5iis along with one of the few K-mount lenses I currently have, the small FA 20-35mm zoom. With the aperture ring on its 'A' setting, in both the viewfinder and the LCD panel, it shows whatever aperture I've selected. But moving the aperture ring to any of its clickable aperture settings, the aperture Info disappears from both the viewfinder and the LCD.

I don't mind keeping the aperture ring in the 'A' position - and using the click-wheels to adjust aperture, in Av mode, if that's what's required - but I'm puzzled as to why the clickable aperture ring doesn't seem to be showing up.

Does some K5iis user more knowledgeable than I have an explanation or advice here?

THANKS in advance!

Your camera and lens are both acting properly. Once you move the aperture ring off of the "A" setting, you disengage the Auto Aperture function. If you are accustomed to MILC lenses which feature aperture rings it can seem strange.

[jumbleview]

That's normal. And I do not think it is K5ii specific. When aperture ring set into A position camera sets lens aperture according to the value selected by camera aperture control. In any other ring position camera can't control aperture. Lens itself can't convey aperture value back to a camera (such interface does not exist neither in lens no in camera).

[pres589]

Pentax crippled the k-mount on their digital cameras with k-mounts like the K-5 IIs. There's no mechanical coupling with the lens to tell the camera the relative position of the aperture ring. So the lens is made to tell the camera where the ring is positioned but the camera has no way to detect this.


Leave the ring in the A position and manipulate the aperture with the controls on the camera body. Everything is working as designed.

[StiffLegged]

My K-7 works the same way with both my A series lenses (which date back to the 1980s) - that’s how it’s meant to work. The aperture ring is to maintain compatibility with older film SLRs!

[pschlute]

have an explanation or advice here?

As said above, this is quite normal. The K mount was "crippled" over 20 years ago before Pentax had even designed a DSLR. As noted above, just put the lens on the "A" setting and you have full control over the aperture via the cameras controls. But this does not mean that you cannot use a lens without an "A" setting, just that there are significant restrictions.

Before the "A" series lenses were introduced, the SMC/smc (K) series and the M series lenses had no A setting on the lens. These would work fine in Av mode on the film cameras because the mount preceded the "crippled" versions in use today.

If you want to use a lens without an "A" setting (or an A-series lens with the ring set to an actual f-stop) on your K5 iis you first need to go into the menu and select "Enable Aperture Ring"

Put the camera in Manual exposure mode and press the green button. The camera will stop the lens down, take a meter reading and select an appropriate shutter speed, this is called stop-down metering Then you can take your shot, and the lens will be stopped down to the aperture you selected on the lens. Of course the aperture used will not be displayed by the camera nor recorded in the exif.

You can actually also use Av mode without having to do a stop-down meter reading, but the lens will not be stopped down during capture, it will always capture at wide open irrespective of what f-stop you have selected.

BTW the latest K3 III camera has automated the stop-down metering and enabled it in Av mode, so it takes place when you press the shutter button, a split second before the actual exposure, but this is the only Pentax DSLR capable of this.

But if you have a lens with "A" setting, just leave it there and you dont have to worry about stop down metering at all.

Hope this helps.

[mlag]

Pentax crippled the k-mount on their digital cameras with k-mounts like the K-5 IIs. There's no mechanical coupling with the lens to tell the camera the relative position of the aperture ring. So the lens is made to tell the camera where the ring is positioned but the camera has no way to detect this.


Leave the ring in the A position and manipulate the aperture with the controls on the camera body. Everything is working as designed.

Indeed, on modern camera bodies to set manual the aperture of lens, you leave the lens on A automatic and use on the body a mode setting like P or Av or... and set the aperture by the rear wheel.....
In other words the the A-lens is under camera control, even in manual modes and hence A on lens should be engaged.

[Des]

As said above, this is quite normal. The K mount was "crippled" over 20 years ago before Pentax had even designed a DSLR. As noted above, just put the lens on the "A" setting and you have full control over the aperture via the cameras controls. But this does not mean that you cannot use a lens without an "A" setting, just that there are significant restrictions.

Before the "A" series lenses were introduced, the SMC/smc (K) series and the M series lenses had no A setting on the lens. These would work fine in Av mode on the film cameras because the mount preceded the "crippled" versions in use today.

If you want to use a lens without an "A" setting (or an A-series lens with the ring set to an actual f-stop) on your K5 iis you first need to go into the menu and select "Enable Aperture Ring"

Put the camera in Manual exposure mode and press the green button. The camera will stop the lens down, take a meter reading and select an appropriate shutter speed, this is called stop-down metering Then you can take your shot, and the lens will be stopped down to the aperture you selected on the lens. Of course the aperture used will not be displayed by the camera nor recorded in the exif.

You can actually also use Av mode without having to do a stop-down meter reading, but the lens will not be stopped down during capture, it will always capture at wide open irrespective of what f-stop you have selected.

BTW the latest K3 III camera has automated the stop-down metering and enabled it in Av mode, so it takes place when you press the shutter button, a split second before the actual exposure, but this is the only Pentax DSLR capable of this.

But if you have a lens with "A" setting, just leave it there and you dont have to worry about stop down metering at all.

Hope this helps.

That's a brilliantly lucid explanation Peter.

Two more helpful PF resources:
How to Use Manual Lenses on Pentax DSLRs - Tutorial Videos | PentaxForums.com
Pentax Green Button Guide - Articles and Tips | PentaxForums.com

One other reason to use the A setting if there is one on the aperture ring. If you set the aperture manually with the ring, the camera doesn't know what aperture is set, so it won't be recorded in the EXIF for the image.

[pschlute]

That's a brilliantly lucid explanation Peter.

Probably because I was completely sober when I wrote it

[MiguelATF]

As said above, this is quite normal. The K mount was "crippled" over 20 years ago before Pentax had even designed a DSLR. As noted above, just put the lens on the "A" setting and you have full control over the aperture via the cameras controls. But this does not mean that you cannot use a lens without an "A" setting, just that there are significant restrictions.

Before the "A" series lenses were introduced, the SMC/smc (K) series and the M series lenses had no A setting on the lens. These would work fine in Av mode on the film cameras because the mount preceded the "crippled" versions in use today.

If you want to use a lens without an "A" setting (or an A-series lens with the ring set to an actual f-stop) on your K5 iis you first need to go into the menu and select "Enable Aperture Ring"

Put the camera in Manual exposure mode and press the green button. The camera will stop the lens down, take a meter reading and select an appropriate shutter speed, this is called stop-down metering Then you can take your shot, and the lens will be stopped down to the aperture you selected on the lens. Of course the aperture used will not be displayed by the camera nor recorded in the exif.

You can actually also use Av mode without having to do a stop-down meter reading, but the lens will not be stopped down during capture, it will always capture at wide open irrespective of what f-stop you have selected.

BTW the latest K3 III camera has automated the stop-down metering and enabled it in Av mode, so it takes place when you press the shutter button, a split second before the actual exposure, but this is the only Pentax DSLR capable of this.

But if you have a lens with "A" setting, just leave it there and you dont have to worry about stop down metering at all.

Hope this helps.

I have to echo Des's comment - and give you my real thanks for what (and I'm using his words, not mine) is, truly, a brilliantly lucid explanation.

I also appreciate everyone else's replies, which were, are and have been uniformly cogent, helpful, and to the point.

And also a quick confession: the K-5iis that I recently acquired is currently my only Pentax DSLR, previous to that I had a KP and several K200d's, excellent cameras one and all, and most of the lenses I used with them tended to be DA Ltd primes. But, simultaneously and in the interim period, I've also used a handful of excellent mirrorless cameras, including Olympuses, Lumixes, and some superb Fujis - with a handful of equally fine modern Fujinon, Zuiko and Panasonic-Leica primes, all of which have clickable aperture rings, which function beautifully, and which I'd gotten into the habit of using with those cameras A or Av modes. Related confession: as a former Pentax film photographer from the ancient analog days (my weapons of choice were MX's, and before that Spotmatics), my old-school preferences have always been for clickable aperture rings as opposed to control wheels. Granted, the wheels of my K-5iis work equally well (and in some cases possibly better) than repositioning my fingers to move an aperture ring... but there's something weirdly satisfying about doing it the old-fashioned way.

But thank you again, Peter, for the logical and detailed explanation.

Quick addendum: after years of shooting mainly DA primes, of the Ltd variety, I'm both surprised and rather delighted by the initial results I'm getting with the tiny, plasticky FA 20-35mm zoom. It appears, as the saying goes, that it punches far above its weight

[HArendsen]

Probably because I was completely sober when I wrote it

[mikesbike]

Quick addendum: after years of shooting mainly DA primes, of the Ltd variety, I'm both surprised and rather delighted by the initial results I'm getting with the tiny, plasticky FA 20-35mm zoom. It appears, as the saying goes, that it punches far above its weight

That is a good lens. No doubt you'll get much good use from it.

As to the aperture ring use, if you have lenses requiring that time-honored but olde-fashioned technology, then at least those lenses are usable, but not without some sacrifice of operation, such as metering options, mode options, and more. If the MF lens does have the "A" setting on the aperture ring, by all means use it, which will open many of these advantages.

We are creatures of habit. I first encountered the use of electronic camera on-body control of the aperture selection upon acquiring my 35mm film Pentax PZ-1p in the late 1990's- my 3rd Pentax SLR over a period of some 15 years. Even though having the 2-wheel controls and not needing the aperture ring, yet the aperture ring was not "crippled" as is the case with Pentax DSLR cameras. If putting one of my old"M" lenses on it, and using the aperture ring to select aperture, if the camera was set to the "P" mode, it would then switch itself to Av operation, setting the appropriate shutter speed. If I had a MF lens with the "A" setting, I could choose to use the aperture ring or not use it and the camera would instantly respond either way. This camera was such a new and strange device to me, I did not even know what "Av" or "Tv" meant! The traditional "aperture priority" or "shutter priority" (preferred), manual, etc were all I knew. At first I found all these new-fangled controls and terms rather off-putting.

But as time went on, I got to wondering as I observed the new camera's functions in action. Very efficient, was my thought as I became more impressed. I had long been aware of the special value in obtaining a constant-aperture zoom lens rather than a variable-aperture one in the same zoom range. The fact of variable-aperture zoom lenses actually changing the aperture value from that set on the aperture ring as the lens is zoomed to a longer FL, a setting of say f/8 would become a value of f/11 etc. Of course, if shooting in an AE mode like Av, the camera would simply change the shutter speed to compensate, as it does also when the lens is zoomed more into the tele range, in order to minimize the effects of shake. But shooting in the Manual mode is a different matter. I wondered, since the aperture could now be set electronically with the camera's own control wheel, if this control could stabilize an aperture that is not wide open when using a variable-aperture zoom lens.

Using my PZ-1p's ability to instantly work fully both ways, I ran some tests, and was amazed and gratified to discover this to be the case- f/8 would indeed remain at f/8 value! It did this because it COULD do it, while the aperture ring was incapable of maintaining aperture value. This was long ago, but I think back then with AF lenses having an aperture ring with an "A" setting, the camera could still give aperture readouts when the ring was engaged. So I could see the aperture change as in f/8 to f/11 etc when using the ring, and not changing when using the camera's electronic aperture control! I ran numerous tests, being careful to turn off AF and train the camera on large expanses of evenly lit surface during bright, cloudless daylight. I even included visual outcome by shooting some slides, which verified a change in exposure when using he aperture ring, and a stable exposure when using the camera's electronic control.

Though not having the PZ-1p's versatility in regards to aperture ring use, using a modern Pentax DSLR, such as your K-5 IIs, you can still test for this advantage for the camera's electronic on-body aperture control very simply. If you have a variable-aperture zoom lens with the "A" setting, especially one have a wider variable range like f/3.5-5.6 or so, first go into camera menus to set "enable" aperture ring use. Then put your mode dial on the Manual setting. You'll need a brightly-lit cloudless day preferably around mid-day, and a large expansive area having the same lighter color and tone, like a driveway for example, or even a lighter toned lawn. Turn the AF off to MF. Have the zoom set to lowest FL which will provide the lens's widest aperture, The lens set to the "A" position. By using the camera's meter indication, set a proper exposure that will also feature a mid-aperture, not wide open at any point along the zoom range. Say that correct exposure will be at f/8 and 1/250 sec shutter speed. Then zoom the lens gradually to the longest FL. The settings should remain stable and the meter should consistently remain centered for correct exposure, even though using a variable-aperture zoom lens! The surface part of the area that fills the frame will be less as zoomed, but should not be different in any other characteristic. Now, select the same aperture by using the aperture ring- in this case f/8, and once again zoom the lens. Now watch the meter indication, which will no doubt now indicate a change in exposure as the lens is zoomed!

These new-fangled changes brought via newer technology, actually do afford us some real advantages! In the case of Pentax, there is also the exclusive Pentax Hyper System. If shooting in "P" mode, for instance, perhaps due to constantly-changing lighting or background, and then a situation arises where you'd prefer a different aperture or shutter speed other than what the camera has chosen, just go ahead and use the thumb or finger dial to select your preference and the camera will simply instantly obey! You are temporarily instantly switched to Av or Tv operation without first having to change your mode dial before making your selection. This is the Hyper Program mode. A touch of the green button instantly restores full "P" mode.

If shooting in the "M" mode, you can use the green button to instantly obtain a meter-centered "correct" exposure. If you'd then rather have a different aperture or shutter speed, first hit the AE-L button to preserve the exposure value, then select your preference of either and the other will follow along to preserve that exposure! This is "Hyper Manual" operation. This green-button ultra-fast setting feature is also an excellent way to quickly spot-meter around a scene to optimize your exposure when using the "M" mode.

These are very efficient Pentax systems for making changes and establishing adjustments on the fly. I was utterly amazed when I first discovered these design advancements, exclusively Pentax, way back when I learned of their appearance on my PZ-1p!

[pschlute]

Then zoom the lens gradually to the longest FL. The settings should remain stable and the meter should consistently remain centered for correct exposure, even though using a variable-aperture zoom lens!

I must admit to being a bit naive when I used variable aperture zooms in the film era. I had it (wrongly) in my head that the variable bit only applied when the lens was set to wide open, when of course it applies throughout the range of apertures. As your tests show, when a lens is set to the "A" position, the camera is able to maintain say f8 throughout the zoom range because it knows it needs to open the iris more physically, as you zoom to longer focal lengths, to maintain f8.

All the Pentax variable aperture zooms from the "K" series through to the FA series would have a little index to the left of the main index for reading the aperture at longer focal lengths, when the aperture ring was not set to "A" (or in the case of "K" and M lenses, had no "A" setting). Some like the M 40-80 2.8-4.0 had two additional indexes, neatly colour coded to enable you to read the aperture correctly at longer focal lengths. This actually led to my further understanding of variable aperture zooms....they are variable at the smallest aperture too. So to take the example of the M40-80 zoom, at 40mm it is a f2.8-f22 lens, and at 80mm it is a f4.0-f32 lens.

[bobore]

I was utterly amazed when I first discovered these design advancements, exclusively Pentax, way back when I learned of their appearance on my PZ-1p!

I had owned just about every Pentax body from the Super Program to the PZ1P. The PZ1P was indeed incredibly capable & comfortable in hand. I carried two of them on trips, and it took my enjoyment of photography to another level.

Today, the camera that fills that roll for me is the OP's choice, the K-5IIs. Although it's technology has been surpassed, it's rock-solid reliability and ergonomics keep me from wandering towards anything else. Guess it's my digital PZ1P!