[shyrsio]

Hi all!
So yesterday I was toying with my MZ-5n, and I noticed that in aperture priority mode(speed selector on auto), with the M 50/1.7, the camera detected every aperture value changes and it compensated in shutter speed.
As far as I know this is not possible in Pentax Dslr, and therefore we have to do step down metering. I imagine at the time Pentax considered the feature obsolete, but now, with more and more attention towards vintage lenses, don't you think it would be a valued feature?

[WhatsMyNameAD67]

I don't know the answer, but it sounds like one of those 'great' ideas that never got replicated in modern cameras like the Eye Controlled Autofocus on my old Canon EOS A2E.

[UncleVanya]

The aperture indicator lever on lenses is a mechanical interface that was removed on low end film cameras first. This is something that has been debated since they first walked away from this.

Pentax/Ricoh: De-cripple the K-mount! PETITION - PentaxForums.com

[torashi]

It was removed because of gradual improvements and forward thinking, e.g. the aperture of newer A, F, FA lenses could be controlled from the body with a dial, like for shutter priority (Tv) or program modes. One less moving part just means better reliability, aka one headache less.
Perhaps an optical readout would be a better modern solution instead of previous designs with a variable resistor, some with chains (like the P67, which is known to get damaged by inexperienced user error).
In any way, this would also mean spending resources and manpower in a feature only manual lens users of the first K and later M series lenses would enjoy. As much as I'd also like a camera with this feature, the resources are better spent somewhere else. And for a weather sealed body to have this feature kind of negates its purpose. They would have to release a companion to the K-1/K-1ii/Knext the way Nikon did with the Df, which wasn't a huge commercial success like the K-1 was, which would also mean that the camera would have to be sold at a premium price because of its low numbers, kind of like a small and compact, non-AW/WR limited edition M-D, only for those who exclusive shoot K and M glass. You see, it wouldn't be a cheap piece of kit.

[Lord Lucan]

this is not possible in Pentax Dslr, and therefore we have to do step down metering

I frequently use M-Series glass on my K-1.

I don't know about other Pentax DSLRs, but what I have to do is to put the K-1 into M mode, select a lens aperture (looking at the lens directly, no viewfinder readout) and then press the green button momentarily while framing the subject. I believe there are other ways of doing it too.

But that is done in less time than it takes to read it, and putting the camera into M mode is done only once, when you fit the lens on. The lack of viewfinder display of aperture is no different from many of the film cameras (eg K1000, K2, ME, ME Super) of the M-Series/film era from which these lenses came. The only extra thing I need to do compared with my old ME-Super is to press the green button momentarily just before I take the shot (after which the aperture returns to fully open for continued framing). So I don't understand what the problem is. In fact it is less work than the K1000 was (a camera that some consider to have been the pinnacle of the film era experience), because on a K1000 instead of a green button you needed to turn the shutter speed dial to place an indicating needle between markers in the viewfinder.

I'm glad that I can use my old lenses on my modern DSLR and Pentax are to be congratulated in making that possible. We are lucky not to be using Canon, Olympus, or certain other brands, although Nikon also allow old lenses. I don't expect a "premium" experience when using a 40 year old lens design - if I want that I use a modern lens.

[shyrsio]

I frequently use M-Series glass on my K-1.

I don't know about other Pentax DSLRs, but what I have to do is to put the K-1 into M mode, select a lens aperture (looking at the lens directly, no viewfinder readout) and then press the green button momentarily while framing the subject. I believe there are other ways of doing it too.

But that is done in less time than it takes to read it, and putting the camera into M mode is done only once, when you fit the lens on. The lack of viewfinder display of aperture is no different from many of the film cameras (eg K1000, K2, ME, ME Super) of the M-Series/film era from which these lenses came. The only extra thing I need to do compared with my old ME-Super is to press the green button momentarily just before I take the shot (after which the aperture returns to fully open for continued framing). So I don't understand what the problem is. In fact it is less work than the K1000 was (a camera that some consider to have been the pinnacle of the film era experience), because on a K1000 instead of a green button you needed to turn the shutter speed dial to place an indicating needle between markers in the viewfinder.

I'm glad that I can use my old lenses on my modern DSLR and Pentax are to be congratulated in making that possible. We are lucky not to be using Canon, Olympus, or certain other brands, although Nikon also allow old lenses. I don't expect a "premium" experience when using a 40 year old lens design - if I want that I use a modern lens.

Yes, that is step down mettering, but it requires a press of the green button, meanwhile with the aperture simulaor this happens in real time.

[mikesbike]

It was removed because of gradual improvements and forward thinking, e.g. the aperture of newer A, F, FA lenses could be controlled from the body with a dial, like for shutter priority (Tv) or program modes. One less moving part just means better reliability, aka one headache less.
Perhaps an optical readout would be a better modern solution instead of previous designs with a variable resistor, some with chains (like the P67, which is known to get damaged by inexperienced user error).
In any way, this would also mean spending resources and manpower in a feature only manual lens users of the first K and later M series lenses would enjoy. As much as I'd also like a camera with this feature, the resources are better spent somewhere else. And for a weather sealed body to have this feature kind of negates its purpose. They would have to release a companion to the K-1/K-1ii/Knext the way Nikon did with the Df, which wasn't a huge commercial success like the K-1 was, which would also mean that the camera would have to be sold at a premium price because of its low numbers, kind of like a small and compact, non-AW/WR limited edition M-D, only for those who exclusive shoot K and M glass. You see, it wouldn't be a cheap piece of kit.

This is the best explanation I have seen. And it rings true. In this light, I think Pentax, in making this decision many years ago, has come up with the best compromise- so vintage MF lenses CAN still be used successfully! I often think of our most advanced AF 35mm film bodies years ago (which I still have but rarely use), how comparatively lightweight they were even though full-frame. But that is just the way it is with DSLR technology, loaded with electronics, compared with the technically simpler older cameras loaded with film. Then I think- WOW, look all of what we have today we did not have then, with WR lenses and bodies, mostly at reasonable cost, adjusting for money value, which provide many more parameter adjustments, both on-site in-camera and by post process, unthinkable 25 years ago! The compact metal-body WR KP, with its numerous grips and its many, many features, able to deliver fine imaging at a higher ISO than we could have imagined, compared with say the MZ-S that we were happy to have back when we could not have dreamed of a KP in our wildest dreams! And look how much we spent on film! Over a few years time, even with casual use, together with the cost of a less-capable camera, it was enough to buy a K-1 II! No complaints from me.

[shyrsio]

It was removed because of gradual improvements and forward thinking, e.g. the aperture of newer A, F, FA lenses could be controlled from the body with a dial, like for shutter priority (Tv) or program modes. One less moving part just means better reliability, aka one headache less.
Perhaps an optical readout would be a better modern solution instead of previous designs with a variable resistor, some with chains (like the P67, which is known to get damaged by inexperienced user error).
In any way, this would also mean spending resources and manpower in a feature only manual lens users of the first K and later M series lenses would enjoy. As much as I'd also like a camera with this feature, the resources are better spent somewhere else. And for a weather sealed body to have this feature kind of negates its purpose. They would have to release a companion to the K-1/K-1ii/Knext the way Nikon did with the Df, which wasn't a huge commercial success like the K-1 was, which would also mean that the camera would have to be sold at a premium price because of its low numbers, kind of like a small and compact, non-AW/WR limited edition M-D, only for those who exclusive shoot K and M glass. You see, it wouldn't be a cheap piece of kit.

I totaly get it. It is progress after all, thats why now we have the KAF4 mount and the actuating lever is also missing, everything is electro-mechanical, and it is a normal evolution. It just disrupts the long line of compatibility which makes Pentax famous. I would dig it if Pentax released some low cost vintage looking full frame camera with just the basic features, including the aperture simulator, for shooting old lenses.

[noblepa]

I totaly get it. It is progress after all, thats why now we have the KAF4 mount and the actuating lever is also missing, everything is electro-mechanical, and it is a normal evolution. It just disrupts the long line of compatibility which makes Pentax famous. I would dig it if Pentax released some low cost vintage looking full frame camera with just the basic features, including the aperture simulator, for shooting old lenses.

This sounds a little like the suggestion that surfaces periodically, to produce a "digital K-1000". That is, a bare-bones camera, all manual, like the classic film camera.

The problems are several fold.

First, as much as those of us here might like such a camera, there is virtually zero market for it outside of this and similar forums.

A little money might be saved by omitting the auto-focus motor, but, again, the general photo market place has come to expect auto focus in all cameras.

Adding the aperture simulator lever would be a physical change that would cost real money, and appeal only to those few who use manual lenses. Again, a very limited market.

Most of the features in modern digital cameras are software-driven. That means that the costs of development have already been spent. I'm sure that the firmware in Pentax cameras (as well as Nikon, Canon, Fuji, Sony and all the rest) is modular and reused from one camera to the next, with minor modifications. So, no savings on development costs.

It costs the same to burn 10GB of firmware onto the microchip as it would to burn 1GB. So, little to no difference in manufacturing cost. Therefore, no reduction in the retail price.

The net result of all this is that such a camera would have limited market potential, which would drive the cost up, with no savings in manufacturing costs. It would be a high-priced, niche market camera. Pentax doesn't have the brand recognition or loyalty to produce a niche camera.

[Just1MoreDave]

Look at page 10 of the MZ-5n manual where the lens compatibility chart is. Even the aperture simulator doesn't make M/K lenses completely compatible. The simulator also relies on the lens to be still adjusted correctly. Most are not adjusted annually as recommended in the manual. What you'd get is an unreliable partial incompatibility, not a lot better than stop down metering.

[mikesbike]

Another thing is, when an aperture ring is required by the camera body design, it is always better when using a zoom lens, that it be a constant-aperture type. With variable-aperture zoom lenses, which most are, the system will not work right as the aperture will vary when zoomed, which in M mode will cause exposure inaccuracy. In Av mode, the shutter speed will of course vary as it can, as the zoom lens is set at various focal lengths with such a camera body, as it does with modern cameras. This is not problematic with camera bodies having electronic control of the aperture via the camera body. There are some film bodies that can instantly switch to aperture ring or control via the body, which is the best possible design. Again, I think Pentax has made a very good compromise decision on behalf of old MF lenses still being quite usable, though not in the best possible way as that would not be cost-effective.

[Lord Lucan]

With variable-aperture zoom lenses ... the aperture will vary when zoomed, which in M mode will cause exposure inaccuracy. ..... This is not problematic with camera bodies having electronic control of the aperture via the camera body

Why is it not problematic when the camera body controls the aperture? How does the camera know how the aperture varies with zoom? Does it have a database of all the lenses that might be fitted? If it does have a database I guess it would only cover modern Pentax lenses.

What I had not realised until recently is that the aperture indicator lever on the mechanical lenses did not give a direct aperture indication to the camera body. It gave a relative indication, at least in the case of the mechanical K and M-Series lenses (I don't have any A-Series). If you look at the bayonet end of those lenses with the aperture at maximum, the position of the lever is the same in all cases, even if the maximum apertures are different. When you turned the aperture ring with the lens on the camera, the camera (of that era) was being told that the picture would be taken at a certain number of stops less than the meter was seeing during framing. With the K and M-Series cameras (at least) the final exposure (controlled by shutter speed if in aperture priority mode) or the shutter speed recommendation (if in manual mode) was calculated on that basis.

The LX, although of the M-Series era, was a bit different in that it had Off-The-Film metering. In manual mode it acted similarly to the above, but in AUTO mode it watched the curtain and film surfaces during the exposure and released the second curtain when it had measured that the film would be exposed enough - the meter did not need to know anything about the aperture.

[Rondec]

Pragmatically, Pentax has little impetus to add functionality to pre-A series lenses. Of course they could, but it likely wouldn't be a strong selling point for new Pentax cameras and the time invested in that sort of endeavor would take away from those committed to bringing better tracking auto focus, better metering, etc to new cameras.

Even though they are old lenses, they are still very usable via stop down metering and that is something, although human nature being what it is, we always want more.

[Not a Number]

Short answer: The aperture linkage could be restored but it isn't going to happen.

The numerous times Adam or some other PF staffer has asked Ricoh the answer has been more or less "no"

Example (from the 2014 CP+ interview):

"Question 8: Many of our Pentax DSLR users have been asking for a camera with a “de-crippled” K-mount that includes the aperture coupler, similar to how you designed the 645D mount with aperture ring support. Is this something you would consider doing?

There are fewer and fewer lenses available on the used market as time goes on. Also, it’s a completely analog operation, so the metering is not as accurate as current technology. For those two reasons, we are not prioritizing to reintroduce this function."

CP+ 2014 Interview with Pentax in Japan - CP+ 2014 | PentaxForums.com

Refer also to these threads:
Pentax/Ricoh: De-cripple the K-mount! PETITION - PentaxForums.com
Thoughts on the crippled K mount. - PentaxForums.com
"Crippled" mount or not? - PentaxForums.com

As far as I know that last "uncrippled" Pentax camera was released in 2001, the MZ-6 / MZ-L / ZX-L.

The arguments haven't changed in at least eight years and neither is Ricoh likely to change their minds.

[Just1MoreDave]

Why is it not problematic when the camera body controls the aperture? How does the camera know how the aperture varies with zoom? Does it have a database of all the lenses that might be fitted? If it does have a database I guess it would only cover modern Pentax lenses.

The autofocus lenses (F series and later) tell the camera body their maximum aperture at the zoom position you've set. A series lenses can only tell the camera one maximum aperture. For example, the Pentax-A 35-70mm f3.5-4.5 is optically the same as the Pentax-F 35-70mm f3.5-4.5, but on a modern camera body, the A version appears to always have a maximum aperture of f3.5. At 70mm the A version would underexpose when the body controls the aperture. A variable aperture M series lens is potentially more accurate for exposure because you'd have to do stop-down metering, but some bodies aren't great at stop down metering and none can do matrix metering.

What I had not realised until recently is that the aperture indicator lever on the mechanical lenses did not give a direct aperture indication to the camera body. It gave a relative indication, at least in the case of the mechanical K and M-Series lenses (I don't have any A-Series). If you look at the bayonet end of those lenses with the aperture at maximum, the position of the lever is the same in all cases, even if the maximum apertures are different. When you turned the aperture ring with the lens on the camera, the camera (of that era) was being told that the picture would be taken at a certain number of stops less than the meter was seeing during framing. With the K and M-Series cameras (at least) the final exposure (controlled by shutter speed if in aperture priority mode) or the shutter speed recommendation (if in manual mode) was calculated on that basis.

Exactly. For those cameras, the aperture lever on the lens only needs to be accurate in two positions. Wide open is one, for a bright viewfinder and easy focusing. Then it needs to stop down to an aperture that the aperture ring is set to.

When Pentax wanted to add automatic features to the bodies, the new A lenses became deceptively complicated. They continue to work like a K or M series lens when the aperture ring is used. Then if the ring is set to A, the lens contacts switch on and the aperture lever does all the work.

The LX, although of the M-Series era, was a bit different in that it had Off-The-Film metering. In manual mode it acted similarly to the above, but in AUTO mode it watched the curtain and film surfaces during the exposure and released the second curtain when it had measured that the film would be exposed enough - the meter did not need to know anything about the aperture.

There must have been some reason why this system was not used for other bodies, because it could have meant the A lens technology was unnecessary.