[Oakland Rob]

I'm kinda stumped. K-3ii.

I've got an all manual lens, no aperture control. I want to be able to select shutter speed manually, and then have the camera vary ISO automatically. I can easily set an aperture and have shutter speed vary automatically, or both shutter speed and ISO vary per Pentax's program, but I want to fix the aperture (well, it has to be on lens via aperture ring), and fix the shutter, and just have ISO vary. Possible?

[hcc]

Check that your ISO mode is set to Auto. To reset the ISO mode to Auto, press (or keep pushing) simultaneously the ISO button and the Green button.

Hope that the comment may help.

[stevebrot]

I'm kinda stumped. K-3ii.

I've got an all manual lens, no aperture control. I want to be able to select shutter speed manually, and then have the camera vary ISO automatically. I can easily set an aperture and have shutter speed vary automatically, or both shutter speed and ISO vary per Pentax's program, but I want to fix the aperture (well, it has to be on lens via aperture ring), and fix the shutter, and just have ISO vary. Possible?

No, not possible and here is the short explanation:

• You have two choices with lenses the body is not able to control, Av mode and M mode
• All modes other than M, B, and X fail-over to Av mode
• Auto ISO is partially supported in Av mode*
• Auto ISO is not supported in M mode. This is true regardless of lens mounted.**
• The above is true for all Pentax dSLRs

Sorry

For what it's worth, this question is posed about twice a year and when explained is followed up almost immediately by, "But my Sony supports this easily".


Steve

* With lenses lacking the A-contacts Av mode is limited to a single set aperture. For K-mount (auto aperture actuation) lenses, this is generally wide open. For manual aperture lenses, it is the aperture to which the lens is set.
** Some consumer-level models give the appearance of auto-ISO in M mode, but in reality do a silent fail-over to TAv mode.

[Oakland Rob]

But my Sony...is a Playstation!

Thanks for the tip Steve. So on a Pentax-M lens it would be the same as a non-Pentax? Basically if I use an old Russian lens or say the Pentax-M 35mm it behaves the same: it's always in Av mode even if the dial is in Sv, Tv, TAv, or P. Shutter speed varies. At any aperture on the manual dial. I'm afraid that I haven't seen the partial auto ISO you speed of, unless you mean auto ISO in combination with auto shutter speed.

The other thing I can't figure out is that in M, with that K lens, the green button does optical preview, in that it stops down the aperture. Although I have it set to Tv Shift in the E-dial customization.

[StarTroop]

The camera doesn't know what aperture the M lens is set to, so when you press the green button in M mode, the camera will quickly stop down to measure the light, and set shutter speed accordingly. I believe the camera will automatically set the green button to Tv shift when using an M lens, so it isn't necessary to set the green button to Tv shift yourself, unless you wanted it even for non-M lenses.

Also, I don't have any experience with the K3ii, but I don't think it switches to TAv from M mode if you enable auto ISO. I'm also not sure if TAv works at all with M lenses.

Manual lenses will work in Av mode, but only to the extent that it will meter and set shutter speed and auto-ISO correctly at the current aperture, which is wide open on an M lens. The camera will not stop down to any other aperture in Av mode with an M lens. M42 lenses usually have some method of manual stopping down through an action on the lens itself, which means you can manually stop down in Av mode to meter and release the shutter, but easily open back up to widest for focusing and composing.

To summarise, there's no convenient way of having auto-ISo with an M lens. Really, the only functionalw way to use an M lens is in M mode.

[jhankins]

Here is more info:

Pentax Green Button Guide - Articles and Tips | PentaxForums.com

How to Use Manual Lenses on Pentax DSLRs - Tutorial Videos | PentaxForums.com

Manual and M42 Lenses on Pentax DSLRs - Articles and Tips | PentaxForums.com

Manual Focus Lens Choices for Pentax - Articles and Tips | PentaxForums.com

[panonski]

I'm kinda stumped. K-3ii.

I've got an all manual lens, no aperture control. I want to be able to select shutter speed manually, and then have the camera vary ISO automatically. I can easily set an aperture and have shutter speed vary automatically, or both shutter speed and ISO vary per Pentax's program, but I want to fix the aperture (well, it has to be on lens via aperture ring), and fix the shutter, and just have ISO vary. Possible?

yes possible.

1) In menu (under the C - number 27) , you must enable "using apperture ring" function - after that, you must be - in TAV mode.
2) after that you can set ISO to fixed or AUTO :


When you set up all of this, you can play games. You can set up almost every scenario from this mode.

tO set ISO to - auto or fixed :

IF ISO is AUTO, camera not change your shutter speed, just ISO

IF ISO is fixed, your camera change your shutter speed.


If ISO is fixed :

just hit the green button near lcd, and you'll be in ISO AUTO / that's what you're ask for /

If ISO is AUTO:

Press top plate Iso Buton, and change it to some value....
After that you will be back in manual ISO


In shooting you can easily change this modes for ISO, to get what you want
____________________________

Another usefull tip for this mode is to use : +/- exposure compensation button

with hitting it, you can set "+" or "-" in exposure metering - and you can turn your camera to give you exposure you wants exactly !

So you can set various options for yourself....

____________________________

Since I discovered TAV, specially with manual lenses - I just love it, more and more, it's so usefull - - as you can see

---

Last edited by panonski; 03-30-2018 at 02:46 AM.

[stevebrot]

The other thing I can't figure out is that in M, with that K lens, the green button does optical preview, in that it stops down the aperture. Although I have it set to Tv Shift in the E-dial customization.

Time to spend some time playing with the camera. A few points to keep in mind:

• M-mode for Pentax is full manual for the full exposure triangle (shutter, aperture, ISO) regardless of lens mounted
• Default behavior (the only behavior actually) for stop-down metering is Tv-shift
• With very few exceptions*, all K-mount lenses have automatic aperture actuation and remain wide-open on your camera unless manually stopped down to meter or automatically stopped down to make a picture
• M42 lenses must have their aperture set to "M" (manual) or similar to shoot or meter other than wide-open with adapted to a K-mount camera (i.e. always stopped down)

The last two points are important in light of the following last two points:

• Unless your camera detects the "A" contacts, it will not stop a K-mount lens down in other than M, B, or X modes. Auto exposure modes default over to Av mode with both metering and exposures done wide open.
• In practical terms, a manual aperture lens with camera in Av mode will meter according to the set aperture. Many users are quite fond of this behavior.

Play with the camera with your intended lens and notice how it behaves. FWIW, most of the above is in the camera manual, though not in direct language. What is not in the camera manual is information regarding meter consistency. Anecdotal evidence is that green button and "EV scale"** metering in M mode is more consistent and linear than metering in Av mode. This is true even for manual aperture lenses. Yes, the green button does work even when the lens is already stopped down. There may also be an advantage to metering in live view, even if shooting using the regular viewfinder. Meter once and keep the setting until either the subject or the light changes...just like in the old days.


Steve

* Some specialty lenses (e.g. ultra telephoto and tilt-shift) have preset or full manual aperture by design. Another case is a K-mount lens that has been intentionally modified to full-manual aperture.

** Use the optical DOF preview to display an EV scale in the viewfinder...very cool.

[Oakland Rob]

Time to spend some time playing with the camera. A few points to keep in mind:

• M-mode for Pentax is full manual for the full exposure triangle (shutter, aperture, ISO) regardless of lens mounted
• Default behavior (the only behavior actually) for stop-down metering is Tv-shift
• With very few exceptions*, all K-mount lenses have automatic aperture actuation and remain wide-open on your camera unless manually stopped down to meter or automatically stopped down to make a picture
• M42 lenses must have their aperture set to "M" (manual) or similar to shoot or meter other than wide-open with adapted to a K-mount camera (i.e. always stopped down)

The last two points are important in light of the following last two points:

• Unless your camera detects the "A" contacts, it will not stop a K-mount lens down in other than M, B, or X modes. Auto exposure modes default over to Av mode with both metering and exposures done wide open.
• In practical terms, a manual aperture lens with camera in Av mode will meter according to the set aperture. Many users are quite fond of this behavior.

Play with the camera with your intended lens and notice how it behaves. FWIW, most of the above is in the camera manual, though not in direct language. What is not in the camera manual is information regarding meter consistency. Anecdotal evidence is that green button and "EV scale"** metering in M mode is more consistent and linear than metering in Av mode. This is true even for manual aperture lenses. Yes, the green button does work even when the lens is already stopped down. There may also be an advantage to metering in live view, even if shooting using the regular viewfinder. Meter once and keep the setting until either the subject or the light changes...just like in the old days.


Steve

* Some specialty lenses (e.g. ultra telephoto and tilt-shift) have preset or full manual aperture by design. Another case is a K-mount lens that has been intentionally modified to full-manual aperture.

** Use the optical DOF preview to display an EV scale in the viewfinder...very cool.

That helps a lot. I had kinda confused myself because I got my first fully M Pentax lens, which behaves a bit differently than my non-Pentax manuals, and I didn't take into account that fact (which explains the green button behavior; it stops down the Pentax, not the other). Short answer is that M mode is the way to go with manual lenses. Doesn't seem to be a reason to use other modes. Thing is I kind of have been doing this all along. I had my settings go back to default, and I guess I was searching for a setting that never actually existed. I got a soft lens, and you control softness by using the aperture, which is another oddball case for using M mode since it's an FA lens, but doesn't act that way. In any mode but M it's always F4.5, unless you use the aperture ring to go below that, in which case it uses the aperture ring setting (2.8 to 4.5). That really threw me for a while.

[panonski]

Just do what I wrote ...

Its simple

[Oakland Rob]

Just do what I wrote ...

Its simple

Thanks, but on my camera I use non Pentax non-A-setting aperture manual lenses, and in TAv mode, which you describe, BOTH ISO and shutter speed vary. IOW, you cannot have a set fixed shutter speed and have only ISO vary automatically. Steve explained this in his posts.

[monochrome]

Thanks, but on my camera I use non Pentax non-A-setting aperture manual lenses, and in TAv mode, which you describe, BOTH ISO and shutter speed vary. IOW, you cannot have a set fixed shutter speed and have only ISO vary automatically. Steve explained this in his posts.

Meter using DoF Lever instead of Green Button.

Turn off the level indicator in your viewfinder and use DoF lever to meter (pull the Power On switch around the shutter release fully to the right). This turns on the Exposure Indicator Bar in the Viewfinder as Steve wrote. It’s a really cool feature reminiscent of film camera meters - you can see the changes applied as you alter Tv, Av and Ev Comp.

[panonski]

Thanks, but on my camera I use non Pentax non-A-setting aperture manual lenses, and in TAv mode, which you describe, BOTH ISO and shutter speed vary. IOW, you cannot have a set fixed shutter speed and have only ISO vary automatically. Steve explained this in his posts.

do you tried to get fixed Iso in the way I described ?

Just hit once ISO on the top, and do one move on wheel to change the value ?

[Oakland Rob]

do you tried to get fixed Iso in the way I described ?

Just hit once ISO on the top, and do one move on wheel to change the value ?

Yes. I had tried that because I've used it on other lenses. I can change ISO, and I can have auto ISO, but in any mode but M the shutter speed also varies. Steve's posts explain this in more detail.

And yeah, the little EV meter is nice. I had forgotten that was there since I had leveling on for use in other modes. Thanks.

[panonski]

hmmmm.... I don't know then... Right now I'm using old 50 1.7 with AF, and manual aperture ring ...

It works as I describe.... I have one more Zenitar - I 'll give it a try ...