[adwb]

I believe you can also meter using the DOF preview position of the on/off switch of the K5. ( doesn't work on K-30 )

Yes I tried that but can't seem to get meter change that way

[arkav]

I believe you can also meter using the DOF preview position of the on/off switch of the K5. ( doesn't work on K-30 )
Yes I tried that but can't seem to get meter change that way

It works on my K200D, and I believe my buddy uses it on his K7. In theory, you could set your metering to Spot, and you could use it to meter
different parts of your scene to see, for example, if a bright area is going to be blown out, or if a patch of shadow is going to be too dark. Just activate
DOF preview and pan around your scene. Not as fast as pressing the green button, but possibly more reliable.

You have to have the camera configured to do Optical DOF preview ( in the menus ). I would think Optical DOF preview would be the default, but it
might not be.

Unless at some point, Pentax decided to disable this feature on all their cameras....

I always assumed that it was missing from the K-30 because it doesn't have the extra position on the ON/OFF switch.
( you can configure the Raw/Fx button to give you DOF preview, but the meter is inactive )

I assumed it still worked on the K5 since it still has the 3 position switch. Sorry if I've given you false hope.

[Lowell Goudge]

The difference between DOF preview and green button metering is the following

Green button sets the shutter to match the preset aperture, the DOF activates the metering to show you where your exposure with current settings is on the exposure meter. It does not change selections

[arkav]

The difference between DOF preview and green button metering is the following

Green button sets the shutter to match the preset aperture, the DOF activates the metering to show you where your exposure with current settings is on the exposure meter. It does not change selections

Precisely. Green button sets your exposure. DOF preview provides metering. The original poster set he wanted to "use the meter" - I just wanted to highlight that there's the other option for using the meter.

Personally, I didn't like using the green button on my K200D. I found it often didn't give me a good exposure.

Sometimes, I'd spend a lot of time getting the exposure just so (manually) , and maybe the lighting would change slightly, and I'd just want to double check the exposure that I already had set.
Pressing the green button might give me a completely different exposure, and then I'd have to spin the wheel to get back where I was. Clicking DOF preview was nice as it allowed me to check exposure
without changing the settings. Sometimes, you don't want the camera to change anything, you just want to use the meter so you can decide if you want to change the exposure.

I don't use M series lenses as much as I used to, so I don't miss having the DOF preview metering on my K30 as much as I might have. I wouldn't consider getting an old lens for this body unless it has the A setting
on the aperture ring. ( There are times when I wish I could just have a digital back for my MX. Simple, intuitive metering, big bright viewfinder, split prism focus screen, etc. )

[marcusBMG]

The difference between DOF preview and green button metering is the following

Green button sets the shutter to match the preset aperture, the DOF activates the metering to show you where your exposure with current settings is on the exposure meter. It does not change selections

On my K-r the operation of the optical preview is described here:

How to use K mount manual focus lenses on Pentax (and Samsung) DSLR's: metering and other issues, hacks and tricks

The important distinction (over eg K10D/K20D) is that there IS a current meter reading displayed via the Ev bar. i would be interested to know if K5 etc are the same.

[Lowell Goudge]

On my K-r the operation of the optical preview is described here:

How to use K mount manual focus lenses on Pentax (and Samsung) DSLR's: metering and other issues, hacks and tricks

The important distinction (over eg K10D/K20D) is that there IS a current meter reading. i would be interested to know if K5 etc are the same.

The difference between green button and optical preview have been the same on the flagship products since the *istD

I have the *istD, K10, K7, and K5. They are all the same

[adwb]

Regardless of how well the green button selects a exposure and that is affected by the program you have chosen line any way, it does select a working exposure.
On both my k 5 bodies using the exposure preview just shows dof by dark and light areas something I have never found to be any use, and since digital is free you might as well take the picture and dump it if no use than mess with a digital preview I have always thought.
I have never found a use for the optical preview and on my bodies it certainly does not set the exposure as does the green button.

[Lowell Goudge]

Regardless of how well the green button selects a exposure and that is affected by the program you have chosen line any way, it does select a working exposure.
On both my k 5 bodies using the exposure preview just shows dof by dark and light areas something I have never found to be any use, and since digital is free you might as well take the picture and dump it if no use than mess with a digital preview I have always thought.
I have never found a use for the optical preview and on my bodies it certainly does not set the exposure as does the green button.

As I said, the optical preview activates the metering and you can see the exposure (as calculated by the metering system) on the exposure meter in +/- at the bottom of the viewfinder

Sometimes it is nice to see the exposure without changing settings

[adwb]

and as I said on my 2 K5 bodies operating the optical preview does not alter the visual bar scale or an incorrect exposure when in manual mode ;only the green button or turning the dials does.

[arkav]

I have never found a use for the optical preview and on my bodies it certainly does not set the exposure as does the green button.

Well, in some circumstances, optical DOF preview can be very useful - that's why they had it on many film cameras.
It's especially handy with fast lenses, where the DOF you see in the viewfinder is extremely shallow. There could be something awkward behind your subject
that you won't see until the lens is stopped down. I don't use it nearly as often as i should in my own work, but when you're shooting macro,
a shot is easily spoiled by a badly placed twig in the background ( or even in the foreground! ).

When you've got your once-in-a-lifetime shot lined up, you can do a quick DOF preview to check that there isn't something awkward in the background
and if there is, you can shift your shooting position ever so slightly to get the background you want. Having that function on the on/off switch ( as it was on my K200D) puts
it where you can easily access it since your index finger is already on the shutter button. And yes, there are circumstances where chimping might not be an option,
and you have to get your shot without taking your eye from the viewfinder.

With my K-30, I have to use the Raw/Fx button, which I find awkward - I find myself having to search for it ( maybe I'll get used to it eventually ).

That's one standard application for (optical) DOF preview. It's not specific to older K mount lenses. There are probably other uses I'm not thinking of right now.
Like I said, DOF preview was a standard feature on film bodies. Photographers used it. I used it.

By keeping the meter active during DOF preview ( on some digital bodies ), Pentax provided us with a bonus feature: you could use it to do metering with older K mount lenses.

It doesn't set the exposure, which is fine, since we might not want to change the exposure, and the green button does that in any case.
This is another option - just metering, for when you want to check the exposure without altering it. I was disappointed to lose that feature on my K-30,
even though I don't shoot with older K-mount lenses very often. If I was still using my M series macro lens, I would have been royally pissed.
It's unlikely that it would have cost Pentax anything to keep the meter active during DOF preview on the K30. Perhaps they could fix this with a firmware update.
Maybe I should upgrade the firmware to see if they already have.

[Lowell Goudge]

and as I said on my 2 K5 bodies operating the optical preview does not alter the visual bar scale or an incorrect exposure when in manual mode ;only the green button or turning the dials does.

Put the camera in manual!

In manual mode the DOF gives you the metering function. In any auto mode metering is useless because the camera shoots wide open in Av mode regardless

[adwb]

and as I said on my 2 K5 bodies operating the optical preview does not alter the visual bar scale or an incorrect exposure when in manual mode ;only the green button or turning the dials does.

As I said [see above] in manual mode if i set the meter bar to centre in a dark room and the turn towards a window it obviously shows over exposed and IN MANUAL MODE the only way on my 2 K5 bodies to then center the meter is to use either of the dials or alter iso, Using the optical or digital preview does not do any thing to correct the meter or what I see as over exposed on the meter bar is then still shown as as a overexposed image in the digital mode preview

maybe i have special versions.with my two bodies that you do not have

[monochrome]

As I said [see above] in manual mode if i set the meter bar to centre in a dark room and the turn towards a window it obviously shows over exposed and IN MANUAL MODE the only way on my 2 K5 bodies to then center the meter is to use either of the dials or alter iso, Using the optical or digital preview does not do any thing to correct the meter or what I see as over exposed on the meter bar is then still shown as as a overexposed image in the digital mode preview

maybe i have special versions.with my two bodies that you do not have

I believe the distinction is that, in M Mode with a manual lens, I want to correct the exposure using the information the camera gives me by changing the aperture, shutter speed, exposure compensation or (rarely) ISO myself, whereas you want the camera to correct the exposure on your behalf by pushing the Green Button.

I want a digital MX. You want a digital SuperPROGRAM.

Neither option is correct nor incorrect, nor is either option preferable to the other. They're just different ways to use the camera. I'm pleased we each have the option to use a Pentax camera in the fashion that suits our style and objectives.

[marcusBMG]

As I said [see above] in manual mode if i set the meter bar to centre in a dark room and the turn towards a window it obviously shows over exposed and IN MANUAL MODE the only way on my 2 K5 bodies to then center the meter is to use either of the dials or alter iso, Using the optical or digital preview does not do any thing to correct the meter or what I see as over exposed on the meter bar is then still shown as as a overexposed image in the digital mode preview

maybe i have special versions.with my two bodies that you do not have

i think this is normal behaviour with most pentax bodies.

For continuous auto exposure Av is the mode, and you could experiment with the hacks see link above to get Av with the range of apertures

[stevebrot]

How do you like trebuchet?

My personal fav...