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12-09-2020, 09:00 AM   #1
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How to set a minimum shutter speed (with auto-iso) on 645z

As the Tav mode doesn't work with 67 lenses, and as the constructor refuses to allow auto-iso mode in manual, the camera is able to have a minimum shutter speed and auto iso, I mean technically, but the menus don't allow me to make the setting. Is there anyone here who managed to solve this problem ? I'm a street photographer and really need to set up this before being forced to buy a lense just to get this "feature".

12-09-2020, 09:24 AM   #2
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Not directly answering your question since i don't have a 645. On Pentax dslrs of smaller formats there's no function for a min shutter speed. My gr iii has it though. As a workaround, for the dslr I use a combination of higher iso 800 on a sunny day and aperture priority to allow changes in shutter speed while still being fast enough.
12-09-2020, 09:57 AM   #3
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What ae you really trying to do?
Put the camera in AV mode. It can auto-ISO and adjust shutter speed.

Manual - Auto-ISO mode in manual is not an option because it's MANUAL. Everything under the photographer's control.


A lens without aperture data or control such as a 67 lens mounted on the 645Z is not controllable by the camera and no aperture data is provided. So the camera has no way to calculate the aperture part of the equation.
In Av mode, it is trying to give you a viable, properly exposured shot, and the only way to do that is evaluate the meter data, and drive the shutter speed, and/or gain to the sensor (ISO).

There is no minimum shutter speed setting.

Menu - Camera 2
ISO Sensitivity AUTO setting - this can be used to expand the range and behaviour a bit.

Have fun experimenting!
12-09-2020, 10:57 AM   #4
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QuoteOriginally posted by Bruce_D Quote
I mean technically, but the menus don't allow me to make the setting.
That is generally a good clue that the camera cannot do as you ask.

FWIW, this sort of question comes up frequently on this site and the short answer is that your camera does not have a way to set a minimum shutter speed and attempts to do so using auto-ISO settings will be ill-fated (i.e. does not work as one might think). This is true regardless of what lens is being used. I don't do much street work at present, but when I do, it is always done in full manual.


Steve

12-09-2020, 01:09 PM   #5
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QuoteOriginally posted by Bruce_D Quote
As the Tav mode doesn't work with 67 lenses, and as the constructor refuses to allow auto-iso mode in manual, the camera is able to have a minimum shutter speed and auto iso, I mean technically, but the menus don't allow me to make the setting. Is there anyone here who managed to solve this problem ? I'm a street photographer and really need to set up this before being forced to buy a lense just to get this "feature".
Perhaps if you explained the problem clearly you may get more help.

if the cameras does not read the lens, you are limited on the auto modes. Get a modern lens to solve the issue
12-09-2020, 05:54 PM   #6
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Shoot manually. You control everything.
12-09-2020, 06:15 PM   #7
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QuoteOriginally posted by pschlute Quote
Perhaps if you explained the problem clearly you may get more help.
OP is French, living in Japan. Some variations in description are understandable.


Steve

12-09-2020, 06:46 PM   #8
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QuoteOriginally posted by Bruce_D Quote
Seems impossible to set auto-ISO in Manual, it's like that, thay bought the TAV mode to have this feature but with 67 lenses TAV doesnt work, so this auto-iso with a shutter speed and and aperture is missing.
I pulled this over from your introduction (BTW...Welcome to the Pentax Forums!). When using adapted 67 lenses you will not enjoy the full capabilities of the camera. In short, you will be restricted to Av and M modes with center-average metering. Of those, only Av may be used with auto-ISO. There is a lens compatibility table in the Operating Manual. In the English version, it is on page 28.* If you need to control the shutter speed, you will be be using M mode; there is no workaround with adapted 6x7 lenses.

Your option is to consider purchase of one or more lenses made for use with your camera. The A645-series offer good value. If that is not possible, M mode with manual ISO is quite do able, though the approach is old-school, like on your 6x7, only with the option of a quick change of ISO if needed.


Steve

* The manual is poorly written and not very clear is some places. If your camera came with the Japanese-language manual, you can download the English versions from... http://www.ricoh-imaging.co.jp/english/support/download_manual.html

Last edited by stevebrot; 12-09-2020 at 06:51 PM. Reason: more better clarity
12-10-2020, 06:41 AM   #9
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QuoteOriginally posted by DWS1 Quote
Shoot manually. You control everything.
precisely not, I cannot control set the auto-iso. it's bloqued on manual iso, it's a good exemple of "I cannot control everything" something is not available.
Control everything means I can set as I want, not as the camera maker want me to.
On Nikon, manual mode let you use exactly what you want you have a real full control, with Pentax you canot control the use of auto iso or not... Full control means let you choose yourself what you need, not let the menu tell you what you need.

---------- Post added 12-10-20 at 06:44 AM ----------

QuoteOriginally posted by stevebrot Quote
I pulled this over from your introduction (BTW...Welcome to the Pentax Forums!). When using adapted 67 lenses you will not enjoy the full capabilities of the camera. In short, you will be restricted to Av and M modes with center-average metering. Of those, only Av may be used with auto-ISO. There is a lens compatibility table in the Operating Manual. In the English version, it is on page 28.* If you need to control the shutter speed, you will be be using M mode; there is no workaround with adapted 6x7 lenses.

Your option is to consider purchase of one or more lenses made for use with your camera. The A645-series offer good value. If that is not possible, M mode with manual ISO is quite do able, though the approach is old-school, like on your 6x7, only with the option of a quick change of ISO if needed.


Steve

* The manual is poorly written and not very clear is some places. If your camera came with the Japanese-language manual, you can download the English versions from... Operation Manuals Download : Support & Service | RICOH IMAGING
Thank you for welcoming me.

I understand your explanations.
It's just that, this feature is possible, I don't ask the camera to read the aperture, just want it to let me use auto-iso and set the shutter speed or a minimum shutter speed at least. The camera can use AV, that means it adapt (the iso in autoiso for example) to fit my exposure compensation or to get the right exposure, I just want an auto iso mode allowing me to set my shutter speed.

---------- Post added 12-10-20 at 06:48 AM ----------



---------- Post added 12-10-20 at 06:48 AM ----------

Thank you all of you for your opinions and helping me how to find out.

The only possibility I see for nom is to take the advantage to set a high iso on manual mode to have a chance it doesn't get too low... the problem is, I'm used to set quickly 1/20 to get a little bit of visible movement, 1/250 to fix the action, and more while I want to make panning shots... That's a bit annoying to know that the camera CAN do it but the menu ergonomy doesn't allow me to set it up.

---------- Post added 12-10-20 at 06:53 AM ----------

QuoteOriginally posted by stevebrot Quote
That is generally a good clue that the camera cannot do as you ask.

FWIW, this sort of question comes up frequently on this site and the short answer is that your camera does not have a way to set a minimum shutter speed and attempts to do so using auto-ISO settings will be ill-fated (i.e. does not work as one might think). This is true regardless of what lens is being used. I don't do much street work at present, but when I do, it is always done in full manual.


Steve
Street photography production is made in a lot of different ways, me, I need versatility, shoot quickly and get a the right exposure, changing with the front (or rear) dial exposure, have my lens aperture set on a specific aperture, and auto-iso. I'll quickly make it darker or lighter using exposure compensation dial.

Last edited by Bruce_D; 12-10-2020 at 06:54 AM.
12-10-2020, 11:16 AM   #10
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QuoteOriginally posted by Bruce_D Quote
I understand your explanations.
It's just that, this feature is possible
Not with a lens whose aperture cannot be controlled by the camera. This is not something addressable with firmware or with some sort of button hack, it is a hard rule.

QuoteOriginally posted by Bruce_D Quote
Street photography production is made in a lot of different ways, me, I need versatility, shoot quickly and get a the right exposure, changing with the front (or rear) dial exposure, have my lens aperture set on a specific aperture, and auto-iso. I'll quickly make it darker or lighter using exposure compensation dial.
If that is what you need, your choice is to buy a lens made for your camera so that TAv mode is available. In your initial post, you indicated that you should not have to do this, but reduction in feature set is one of the side-effects of shooting with adapted lenses. You basically have the same functionality as on your 6x7, only with focus confirm.


Steve
12-11-2020, 02:46 AM   #11
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QuoteOriginally posted by stevebrot Quote
Not with a lens whose aperture cannot be controlled by the camera. This is not something addressable with firmware or with some sort of button hack, it is a hard rule.



If that is what you need, your choice is to buy a lens made for your camera so that TAv mode is available. In your initial post, you indicated that you should not have to do this, but reduction in feature set is one of the side-effects of shooting with adapted lenses. You basically have the same functionality as on your 6x7, only with focus confirm.


Steve
That's kind of a shame to force customers to buy a lens to use something that could be available without it.
It's "political" pentax don't allow the full acces to the camera in manual mode and that's a problem, while Nikon for example allow user to have a full access to all the possibility in manual, Pentax doesn't allow to set the auto-iso. I just wanted that possible. Maybe if there is a change in the future...

---------- Post added 12-11-20 at 02:50 AM ----------

QuoteOriginally posted by stevebrot Quote
Not with a lens whose aperture cannot be controlled by the camera. This is not something addressable with firmware or with some sort of button hack, it is a hard rule.



If that is what you need, your choice is to buy a lens made for your camera so that TAv mode is available. In your initial post, you indicated that you should not have to do this, but reduction in feature set is one of the side-effects of shooting with adapted lenses. You basically have the same functionality as on your 6x7, only with focus confirm.


Steve
I don't want the camera to access the aperture, just use it's in-body cell to calculate the exposition and set the right ISO, the pentax camera can do this but the menu doesn't.
12-11-2020, 12:21 PM   #12
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QuoteOriginally posted by Bruce_D Quote
That's kind of a shame to force customers to buy a lens to use something that could be available without it.
I think you may be missing something in your understanding of how shutter priority automation works (what you are asking for, in part). That is "kind of a shame". To enlighten...the lens must support aperture control from the camera, something your 6x7 lenses do not do. As for auto-iso in M mode (TAv)...think about this a bit and you may understand how it has similar requirements to shutter priority automation.

I shoot a lot with non-A (cannot be controlled by the body) lenses on my K-3 and believe me, the support for 6x7 lenses on the 645Z is pretty amazing by comparison. You actually have it pretty good. I might add that Ricoh/Pentax does not monitor posts to the Pentax Forums,* so your complaint goes no further than the eyes of those attempting to help you learn how to work with your gear.


Steve

* No relationship to Ricoh Imaging or the Pentax brand.

Last edited by stevebrot; 12-11-2020 at 12:28 PM.
12-14-2020, 10:46 PM   #13
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QuoteOriginally posted by stevebrot Quote
I think you may be missing something in your understanding of how shutter priority automation works (what you are asking for, in part). That is "kind of a shame". To enlighten...the lens must support aperture control from the camera, something your 6x7 lenses do not do. As for auto-iso in M mode (TAv)...think about this a bit and you may understand how it has similar requirements to shutter priority automation.

I shoot a lot with non-A (cannot be controlled by the body) lenses on my K-3 and believe me, the support for 6x7 lenses on the 645Z is pretty amazing by comparison. You actually have it pretty good. I might add that Ricoh/Pentax does not monitor posts to the Pentax Forums,* so your complaint goes no further than the eyes of those attempting to help you learn how to work with your gear.


Steve

* No relationship to Ricoh Imaging or the Pentax brand.
Thank you Steve for your very complete reply!
I already said I just want to auto-iso as the camera is able to mesure the brightness. It's not a technical impossibility I just wanted to know if somebody solved that or not. If not, i'll lose the time to read the exposure mark and set again my iso myself and miss more great moment in my street photography habits... the d810 Nikon bodies are able to do it and I was used to with adapter and hassel lenses for example (without reading anything from the lense)... I'll buy the 75mm FA, I don't really have the choice, I need an autofocus lense, and I'm impressed by this 75mm so I need it.

I'm very impressed by the great explanations, the very various answers from a lot of people, just for that, it's like my experience with the Nikon community, a lot of very kind and various helpful people, I don't regret to be a Pentax user, I love my Pentax 6x7, I love the pentax variety of lenses, and I'm loving more and more my 645z as I use it more and more. Thank you all of you !!

Last edited by Bruce_D; 12-14-2020 at 11:01 PM.
12-15-2020, 12:13 AM   #14
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QuoteOriginally posted by Bruce_D Quote
I already said I just want to auto-iso as the camera is able to mesure the brightness. It's not a technical impossibility I just wanted to know if somebody solved that or not.
If it were technically possible, there would be a work-around, but there is none that allows the equivalent of TAv with 6x7 lenses, or even a basement shutter speed in Av mode with auto-ISO using native Pentax 645 lenses. The D810 implements auto-ISO as a feature that allows a basement shutter speed to be set at which the camera will override the user set ISO, but even then the feature is only supported with CPU lenses. There is no direct Pentax equivalent. Likewise, I don't believe the D810 has a direct equivalent to Pentax auto-ISO, TAv, hyper-program, or hyper-manual features.

Each system has its way of serving the maker's perception of the user's needs.

I hope the 75 FA meets your needs.


Steve
12-16-2020, 07:28 AM   #15
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QuoteOriginally posted by stevebrot Quote
I hope the 75 FA meets your needs.
thanks for your explanation, for sure it will, I was dreaming of that Tav mode... and was only using M mode with auto iso on Nikon.
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