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09-15-2012, 08:00 AM   #1
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Really Newb Questions...(Please Help!)

First I have searched, but all the post I found take for granted that you know how to do this.

So I have read this great book called exposure. Detailing how aperture affects both depth of field and the amount of light of a picture, and how when combined with shutter speed you can achieve the proper exposure at a variety of F-stops by adjusting the the shutter speed to what the meter indicates as a proper exposure. It was great, BUT....

However, they just gloss over how the meter indicated what the proper shutter speed is. And more practically how do you do this with an M lens on a digital body?

So in practice how do I do the following, with a M & a DA lens: (I mean literally how do I actually do these things, do I have to be in M mode? Do I need to use AE lock? What does AE-lock really do?)

1) Take a meter reading (say using the sky on a sunny day).
2) Determine the shutter speed appropriate for that meter reading.
3) Then Focus on my subject and composition
4) Use the meter reading and shutter speed from earlier
5) Take the shot.

Please Help a Newbie out. I want to have some consistency and stop taking a million shots till I stumble into the one I want.

09-15-2012, 08:25 AM   #2
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Morning,

Actually that is an excellent question and you are not the only one to ask. There is a set of excellent references and they are here...First - and you only need to do this once is to tell the camera that you may be using manual lenses and to enable the aperture ring. That is covered in the link above.

In terms of actually shooting, it is extremely easy. The lens has an aperture ring (it has the numbers like 2 2.8 4 5.6 8 11 16 22 on it. These are the f stops. There is a mark on the lens that acts as a center mark that essentially points to the f stop value the lens is set at. So that is the aperture that you will be using - until you change it by twisting the ring in order to physically change it.

The camera automagically meters the light through the lens when you either push the green button and / or the shutter.

When you have the lens off the camera, you can hold it up to your eye and twist the aperture ring and watch the aperture adjust to the various f value settings. You should also hear / feel the "clicks" as the ring goes through the f stops.

hope that helps.....


Last edited by interested_observer; 09-15-2012 at 08:31 AM.
09-15-2012, 08:31 AM   #3
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Here is the sticky from the top of the page which should answer your questions: https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html

In brief, it depends slightly on your camera and since you do not mention which body you have I can only reply generically.

If you read "understanding Exposure" you should understand how this works with a DA lens. The camera will communicate with the lens. So put the camera in Av mode adjust the aperture to what you want and the camera will adjust shutter speed to make a correct exposure.

With M or K lenses (or M42) you need to use stop down metering. On most Pentax cameras this can be done with the green button assuming that button is configured correctly, on the k-x you can also use the +/- button. You also need to enable "use aperture ring" in the menu, read the sticky and it will tell you how.
The procedure is:
1) set camera to M mode
2) set the aperture on the lens using the aperture ring (this will not work with DA lenses because they have no aperture ring)
3) aim at the point you want the meter reading to be taken at
4) press the green button. You should hear the aperture stop down and a meter reading will be taken. This sets the shutter speed to take a correct exposure
5) you can now change either aperture or shutter speed keeping in mind that if you increase one you must decrease the other to keep the exposure correct
6) focus and take your shot
09-15-2012, 08:40 AM   #4
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I will let others much more experienced than me answer your question in greater detail, but in the meantime, it might help to know which DSLR you are using. There are also threads on the forum like this one here that will help. My super simplistic instructions, based on a K-r would be the following:

1. Yes, you need to be in M mode to go fully manual.
2. On my K-r I press the [+/-] button on the top (also labeled Av) to toggle between adjusting aperture and shutter speed.
3. I use the thumbwheel to dial in the aperture I want.
4. Press that [+/-] button again to toggle over to shutter speed
5. If there is a specific shutter speed you're after, like slow on purpose to blur a waterfall or fast on purpose to stop action, use the thumbwheel to dial in that shutter speed.
6. Then watch the little meter that goes from -3 to +3 (in your example you wanted to expose for the sky so you would point at the sky while doing this)
7. Click the ISO button and dial in an ISO that centers that meter
8. Now focus on what your subject and shoot it.

Now, as I said, that's simplistic and the three things, aperture, ISO and shutter speed really work as three legs of a stool. It all depends on what you're after. In my instructions above, you could just as easily have started with an ISO and aperture that you wanted and adjust the shutter speed until the meter reads where you want. Or, if you're following along you can see this coming, you could choose an ISO and shutter speed and adjust the aperture until you get the meter reading you want. Usually, it will be a compromise between all three that give you the exact image you're after but my advice is to experiment with them a lot, Even taking 20 photos of the same subject just to see the effects of each.

That was all for the DA lens, for the M, it's different and there's plenty of threads on here about using old lenses with DSLRs. I highly recommend reading this one. But, to get started, here's my overly simplistic instructions:

1. Set the aperture using the ring on the lens.
2. Press the green button on the top of the camera
3. Focus on your subject and shoot
4. Adjust either ISO or shutter speed and shoot again
5. Repeat step 4 until you like what you've got

Anyway, I know it's a ton of information. It was just a short time ago that I started getting a basic understanding and I have a ton to learn. But it is very fun learning and highly rewarding so keep reading and most importantly, keep shooting!

09-15-2012, 08:45 AM   #5
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Thanks for the fast replies. I read the sticky right away but I still didnt feel like I knew what to do. I will read the articles linked and try some new shots.
09-15-2012, 10:57 PM - 1 Like   #6
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Well I went out and took about 350 shots today with a Screw mount lens. I shot mostly at iso 200, with a 28-105mm Macro lens. I used the green button which is set to tv in manual mode to set shutter speed for shots. I tried to meter off the sky or the subject. In most cases I found the subject to be the better place to meter.

Couple things...
Either method of metering, at any focal length 28 - 105 usually resulted in an underexposed image. So I was constantly increasing shutter time.
Also I was told to meter wide open and then step down to the Fstop I want, which usually lead to alot more shutter speed adjustments. I should really just memorize the increase in shutter speed from aperture 3.5 to 22, because I was mostly jumping from one to the other for either depth of field or detail, and going 1 stop and doubling at a time was time consuming.

Most of the things were pretty easy to deal with; here are the things that weren’t:
  • Manually focusing in dim to dark light with glasses on; I focused on the background on more than one occasion and couldn’t tell on the LCD. Any Tips?
  • Manually focusing in general was a PITA
  • Slow shutter high aperture night shots, just couldn't get the tail light glow and focus right
  • AND OMG getting the adapter out of my K-x was so hard!
Is the official pentax m42 adapter easier to get out of the body? Jeeze I thought I was going to scratch or break something every time,
Is there some trick I don’t know about?

Bottom 3 pics are shopped. The third shot I lowered the the highlights and raised the exposure, 4th shot I added the bokeh, 5th shot I played with the exposure and curves.

Go Easy on my Ive owned a camera for less than a week.
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09-15-2012, 11:23 PM   #7
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QuoteOriginally posted by dappercorpmonkey Quote
Go Easy on my Ive owned a camera for less than a week.
You could certainly have fooled me! These are nice shots actually, very nice!
09-15-2012, 11:34 PM   #8
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QuoteOriginally posted by newmikey Quote
You could certainly have fooled me! These are nice shots actually, very nice!
Thanks! I have been reading pretty much nonstop, when not at work. This is the first shot I took, with my first lens, the 50-200mm kit lens. Mostly playing with photo bracketing and HDR.

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09-16-2012, 01:11 PM   #9
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I would say you are doing pretty good, manual focus takes lots of practice and you are doing well.

The Pentax M42 adapter is indeed much easier to put on and take off. It is expensive and sometimes hard to find but if you are serious about M42 I would recommend it.

Most M42 lenses will have a slight error in exposure when used on modern cameras. I am not sure why but it is there. Unfortunately it is not consistent across different lenses and can change even on the same lens at different apertures. However, you do have the exposure compensation button, simply take a few test shots, determine what the error is and dial that into the exposure compensation. It is not 100% but I find it is close enough for me.

The focusing screen in modern cameras is designed to work best with auto focus lenses, not manual focus. The screen can be changed out in most cameras to one that is better for manual focusing. Not sure what camera you have but I changed the screen in my k-x and it helped a lot.
09-17-2012, 07:49 PM   #10
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QuoteOriginally posted by jatrax Quote
I would say you are doing pretty good, manual focus takes lots of practice and you are doing well.

The Pentax M42 adapter is indeed much easier to put on and take off. It is expensive and sometimes hard to find but if you are serious about M42 I would recommend it.

Most M42 lenses will have a slight error in exposure when used on modern cameras. I am not sure why but it is there. Unfortunately it is not consistent across different lenses and can change even on the same lens at different apertures. However, you do have the exposure compensation button, simply take a few test shots, determine what the error is and dial that into the exposure compensation. It is not 100% but I find it is close enough for me.

The focusing screen in modern cameras is designed to work best with auto focus lenses, not manual focus. The screen can be changed out in most cameras to one that is better for manual focusing. Not sure what camera you have but I changed the screen in my k-x and it helped a lot.
I have a K-x, I am considering changing the screen in the body to a split+prism. I am a little worried about losing the ability to spot meter though. Maybe, I am too concerned about it, however I was under the impression that the best way to take a backlit shot with the subject clearly visible like the one below is through spot metering. Otherwise when doing back-lit shots you would wind up limited to silhouettes.
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09-17-2012, 08:57 PM   #11
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QuoteOriginally posted by dappercorpmonkey Quote
Otherwise when doing back-lit shots you would wind up limited to silhouettes.
There are some reports of split prism focus screens altering the ability to spot meter. The Katz-Eye site says this is only a factor on lenses faster than f/2.8. I don't use spot metering, so no problem for me. But giving up spot metering is not going prevent you from taking that shot, I would have taken a center weighted reading, then a test shot and then adjusted the exposure for what I wanted. Not as fast as using spot metering perhaps but with digital it works just fine.

But if that is a concern then stick with the stock screen. I changed out the screen in my k-x and it made a lot of difference. I still have the stock screen in the k-5 and doubt I will bother changing it as I can manually focus just fine with the stock one on the k-5 as opposed to the k-x which gave me problems.
09-19-2012, 05:39 AM   #12
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My K-x and K200D consistently underexpose slightly when using the green button to meter with manual lenses, just FYI. But I can't remember if this is only the case when I have the Katzeye screen in (I only have one so I switch it between bodies as desired). Whatever the case, I usually find myself having to tick the shutter speed one tick slower to get a better exposed photo.
09-19-2012, 10:39 AM   #13
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Is katzeye better than the focusingscreen.com nikon
09-19-2012, 11:49 AM   #14
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QuoteOriginally posted by dappercorpmonkey Quote
Is katzeye better than the focusingscreen.com nikon
I can't say for certain, since I don't have both kinds, but I will say that if I were going to get another one, I'd try focusingscreen.com. The Katzeye was quite expensive ($160 since I got the Optibrite treatment) and I wouldn't have gotten it if I hadn't received a generous subsidy/present from family. But focusingscreen.com is almost certainly better than the stock focusing screen you have now.
09-23-2012, 01:56 PM   #15
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I'm not sure on the K-x, but the K20D only used center weighted metering when the aperture ring was in use. On the K-30, multi segment metering doesn't work with the manual lens according the manual, it doesn't mention spot.
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