[maxfield_photo]

Ah, ok, you have a manual lens. Actually I think it's an 'A' (for automatic) that you want on your aperture ring, not an 'M'. The 'A' setting allows the camera body to control the aperture rather than the lens. So for instance, in shutter priority mode, Tv, you can set the shutter speed you want to use, and the camera will open or close the aperture on the lens accordingly in order to give what it thinks is the correct exposure. But you can still find the correct exposure with a gray card using the lens you already have. Try this:

1) Press the Menu button and find the custom menu option "allow aperture setting other than A", make sure it is set to "allowed". When you attach the lens to your camera the back screen will ask you to "input focal length" This is for the shake reduction feature. If you have a 50mm prime for instance, select 50mm. If you have a zoom lens, you'll have to remember to change it as you zoom.
2) Place your gray card in the scene you want to photograph.
3) Set the mode dial on your camera body to 'M'anual, and select the aperture you want to use by twisting the ring on your lens. For portraits or macro, try using your widest aperture (probably f/4 or maybe f/2.8). For landscapes try using a narrow aperture f/11 or f/16. Since you know Sunny 16, you can double check yourself.
4) Fill your frame with the gray card. This may require zooming with your feet (i.e. walking up to it)
5) Press the green button. This will take a reflected meter reading of your scene and try to average it out to 18% gray. But guess what, your scene (i.e. the gray card) is already 18% gray, so the camera won't be fooled by the color, sheen, or backlighting of objects in your scene.
6) Simply remove the gray card and start shooting. Since your camera is in manual mode, every shot will have the same "correct exposure".

Please note though, there are lenses with 'M's on them. The old Takumar lenses have what's called a diaphragm clutch that could either be set to Auto or Manual, and some just have an 'A' or 'M' abbreviated. Don't confuse this with the 'A' found on an aperture ring. That sits just past the narrowest aperture setting, usually f/22.

Here are two sticky posts that you might want to read:
Using Manual Lenses (M42 Screwmount, M , K) on Pentax DSLRs
Usage of the Green Button

Good luck, let us know if you are still having trouble.

---

Last edited by maxfield_photo; 11-21-2011 at 07:18 PM.

[eddie1960]

I wanted to thank you all for your replies and thoughtful comments. It gave me the start to identifiying my problem. Apparently you have to have lenses that have the m setting on the aperture ring and apparently mine are too old, they date back to my film days 30 years ago. I borrowed a friend's lens with the m setting and it worked like you all said.

I will have to figure out a way to determine exposure apart from from the gray card or buy newer lenses. I used to have an exposure meter long ago but it got wet and never worked again. Anybody use the sunny 16 rule?

I usually only use Sunny 16 when I'm shooting Negative film which has enough latitude. Slides I always meter since they aren't forgiving
The other problem is sunny 16 doesn't work all that well when you live in Canada and it's winter I usually go a stop more than the rule. Sunny days with lot's of snow of course may be different

[Ccat]

Ah, ok, you have a manual lens. Actually I think it's an 'A' (for automatic) that you want on your aperture ring, not an 'M'. The 'A' setting allows the camera body to control the aperture rather than the lens. So for instance, in shutter priority mode, Tv, you can set the shutter speed you want to use, and the camera will open or close the aperture on the lens accordingly in order to give what it thinks is the correct exposure. But you can still find the correct exposure with a gray card using the lens you already have. Try this:

1) Press the Menu button and find the custom menu option "allow aperture setting other than A", make sure it is set to "allowed". When you attach the lens to your camera the back screen will ask you to "input focal length" This is for the shake reduction feature. If you have a 50mm prime for instance, select 50mm. If you have a zoom lens, you'll have to remember to change it as you zoom.
2) Place your gray card in the scene you want to photograph.
3) Set the mode dial on your camera body to 'M'anual, and select the aperture you want to use by twisting the ring on your lens. For portraits or macro, try using your widest aperture (probably f/4 or maybe f/2.8). For landscapes try using a narrow aperture f/11 or f/16. Since you know Sunny 16, you can double check yourself.
4) Fill your frame with the gray card. This may require zooming with your feet (i.e. walking up to it)
5) Press the green button. This will take a reflected meter reading of your scene and try to average it out to 18% gray. But guess what, your scene (i.e. the gray card) is already 18% gray, so the camera won't be fooled by the color, sheen, or backlighting of objects in your scene.
6) Simply remove the gray card and start shooting. Since your camera is in manual mode, every shot will have the same "correct exposure".

Please note though, there are lenses with 'M's on them. The old Takumar lenses have what's called a diaphragm clutch that could either be set to Auto or Manual, and some just have an 'A' or 'M' abbreviated. Don't confuse this with the 'A' found on an aperture ring. That sits just past the narrowest aperture setting, usually f/22.

Here are two sticky posts that you might want to read:
Using Manual Lenses (M42 Screwmount, M , K) on Pentax DSLRs
Usage of the Green Button

Good luck, let us know if you are still having trouble.

Thank you for your reply and the post. They were very helpful. Had a little bit of a break with the thanksgiving holiday so I will get to practice.

This is a very helpful community and I appreciate everyones help!

[Culture]

Do all pentax cameras have this function? I dont seem to know if my exposure is under or over with my k-m.

In manual mode the exposure compensation can not be changed

[glanglois]

Do all pentax cameras have this function? I dont seem to know if my exposure is under or over with my k-m.

In manual mode the exposure compensation can not be changed

No, in manual mode the exposure comp cannot be "changed" as it does not exist. Exposure comp is a manual correction to the exposure computed by the camera operating in one of the auto modes. But in manual mode, you're already setting all exposure factors yourself to begin with. No need for a manual override of your own manual settings. Make sense?

By the way, the exposure versus white balance conversion may arise from the facts that a typical grey card will be manufactured at 18% of the area covered with black pigment. The result is a grey appearance (at a distance). On the other hand, the camera is programmed to adjust exposure to the equivalent of about 18% of the scene black if the rest is bright white. So it turns out that the card can be used to set white balance and an average exposure. If it were just white balance we were looking for, a 30% or 10% grey card would be fine. So the card is a double-duty tool and us newbies get twice as confused.

[Mike Cash]

My K-5 has a display like what you're talking about. I would be surprised if the K200D has one, though. You may be looking for something that just ain't there. I've never heard of an "m" setting on the aperture ring, and I have Pentax lenses dating back 1957 through the present.

I sometimes shoot Sunny 16. It's not that hard.

[bluestringer]

Yes, the K200D has that scale. If your are shooting in manual with the lens on A, the 0.0 scale will show on the right side in the viewfinder and also on top in the LCD display. If you are shooting manual with the lens set to other than A, or using a non A lens, the 0.0 scale will show on the right side of the viewfinder and in the top LCD with the depth of field preview check with the setting optical preview. You must have optical preview set in the C settings.


bluestringer

[Marc Sabatella]

Seems to me there has been some misinformation in this thread. To answer the OP's original question, you don't need an M lens or a lens with an aperture ring. you just need the camera to be in M mode. He probably had it in P or Av or Auto or some other mode, and that why the meter always read 0. With the camera in M mode, it should be just like the Nikon the teacher used (which also would have been in M mode) even with the kit lens, except that the meter display is numeric only instead of numeric plus a scale. Hopefully he eventually figured that out.

So to the answer the new question, well, all Pentax cameras have a meter. Couldn't work very well without one. In M mode with a "modern" (auto exposure) lens, the meter reading always displays, because the camera knows the selected aperture. In M mode with an old lens (manual exposure), or with a modern lens that has an aperture ring but it is not in the "A" position like it should be, the meter only displays while doing a DOF preview. Almost all Pentax have that function, but I sort of remember that maybe the K-m and DL were two models that lacked this feature. If that is true, then there is no way to see the meter. But the "green button" method of pressing a button to have the camera stop down momentarily to automatically stop down, take a meter reading, and set an appropriate shutter speed that zeroes the meter, works on *all* Pentax DSLR's. It's just the specific button to press that differs between models. Read the sticky thread at the top of this forum for info on how to use manual lenses.

[Anvh]

On the other hand, the camera is programmed to adjust exposure to the equivalent of about 18% of the scene black if the rest is bright white. So it turns out that the card can be used to set white balance and an average exposure.

Don't know where that comes from for lightmeters but it isn't true.
18% grey comes from printing industry where like you said where 50% white and 50% black gives you 18% or so called neutral grey.

Light meters on the other hand don't use that for their exposure.
According to "American National Standard for General-Purpose Photographic Exposure Meters (Photoelectric Type)" ANSI PH3.49-1971 it's actually 12,3% so with a 18% grey card you need to overexpose with 1/2 a stop to get the correct exposure.

[RioRico]

Marc has nailed it. We *can* meter manually with any lens, and we *should* know how to. When I'm shooting in stable light conditions, I'll meter manually with A-type and AF lenses and leave the exposure set for the duration. Still, we should know just what the metering is doing, and why.

If we use spot or center-weighted or matrix metering, we're reading light that's reflected off some portion of the subject and its vicinity. That light can vary widely with a contrasty subject field. When we meter off a gray card near the subject, or use an incident light meter, or apply the Sunny-16 Rule, we're reading light that falls on the subject. That ambient light changes with the source, not with the subject field.

Let's say I'm shooting desert 'scapes (I like to use Sedona AZ as an example). The subject field contains red rocks, gray mountains, bright green foliage (after a rain), dark green trees, blue sky, white puffy clouds, various buildings. With auto metering, every shot has a unique exposure. With a gray card, I read the light that illuminates everything, not the light that each point reflects in its own way. Each frame has varying proportions of reds-grays-greens-blues-whites-whatever, but they're all exposed the same as the light remains constant. When light changes, meter again. This method most closely approximates why I see of the scene.

[Culture]

Seems to me there has been some misinformation in this thread. To answer the OP's original question, you don't need an M lens or a lens with an aperture ring. you just need the camera to be in M mode. He probably had it in P or Av or Auto or some other mode, and that why the meter always read 0. With the camera in M mode, it should be just like the Nikon the teacher used (which also would have been in M mode) even with the kit lens, except that the meter display is numeric only instead of numeric plus a scale. Hopefully he eventually figured that out.

So to the answer the new question, well, all Pentax cameras have a meter. Couldn't work very well without one. In M mode with a "modern" (auto exposure) lens, the meter reading always displays, because the camera knows the selected aperture. In M mode with an old lens (manual exposure), or with a modern lens that has an aperture ring but it is not in the "A" position like it should be, the meter only displays while doing a DOF preview. Almost all Pentax have that function, but I sort of remember that maybe the K-m and DL were two models that lacked this feature. If that is true, then there is no way to see the meter. But the "green button" method of pressing a button to have the camera stop down momentarily to automatically stop down, take a meter reading, and set an appropriate shutter speed that zeroes the meter, works on *all* Pentax DSLR's. It's just the specific button to press that differs between models. Read the sticky thread at the top of this forum for info on how to use manual lenses.

Yes this is the problem that I seem to have. I have the k-m, and when people talk about metering i get confused because I dont see any metering. The camera sees what it sees and that is it.

So if I understand right, the metering scale is different from the exposure compensation, and both can be changed independently.

what is the disadvantage of not having a metering scale and how does that affect your pictures?

[bluestringer]

The K-m does show the exposure meter scale when shooting in manual mode. It's in the right bottom corner of the LCD panel. Check the using manual mode of the manual starting on page 98.

bluestringer

[glanglois]

Don't know where that comes from for lightmeters but it isn't true.
18% grey comes from printing industry where like you said where 50% white and 50% black gives you 18% or so called neutral grey.

Light meters on the other hand don't use that for their exposure.
According to "American National Standard for General-Purpose Photographic Exposure Meters (Photoelectric Type)" ANSI PH3.49-1971 it's actually 12,3% so with a 18% grey card you need to overexpose with 1/2 a stop to get the correct exposure.

It appears that it came from my ignorance. I seem to have misunderstood (or forgot) something I read. Thanks for the correction.

[Culture]

The K-m does show the exposure meter scale when shooting in manual mode. It's in the right bottom corner of the LCD panel. Check the using manual mode of the manual starting on page 98.

bluestringer

I have not checked this. But isnt that supposed to be the exposure compensation value. And in M mode that cannot be changed.

Please explain more if I am wrong

[bluestringer]

It is the same as the exposure comp. But in manual it will let you know if the exposure is over. under, or neutral. You can adjust as needed. I'm not sure how it would work with a non A lens if the user sets the aperture on the lens. You can use the Av button, and the camera will set the correct shutter speed to go along with the user set aperture. You could also try the DOF preview at the on/off switch and see if it will pop up the exposure comp meter to let you know if you have the right exposure.

bluestringer