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03-09-2009, 07:36 PM   #1
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Just starting with digital and M42 lenses

Help! I haven't done much real photography since my days with Pentax Spotmatic (mid-1970s). Recently upgraded to 100D, and trying to use by old SMC Takumar lenses.

1. I have a Pentax adapter, but lenses do not seem to attach so that aperture scale is square to top of camera (so reading is off center). Seems like this means that full focus range is compromised. Correct? Any suggestions?

2. I can't seem to get an EV reading (in Manual mode) when I set aperature at f-stop desired and use e-dial to change shutter speed. What am I doing incorrectly?

03-09-2009, 07:48 PM   #2
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1. Don't know. Haven't used an M42 yet.

2. In the Menu, go to Custom and set the Preiview Method to Optical. Then hold the Preview switch (OFF/ON/Preview) and it will now display in the VF.
03-09-2009, 07:57 PM   #3
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Wonderful! Many thanks.
03-09-2009, 08:58 PM   #4
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Is the adapter a genuine Pentax M42-K adapter, or third party? Does that happen with all your M42s?

If it's 3rd party, it may just be QC issue. If it's genuine Pentax adapter, and happens with all your M42s, then it might be defective; very strange. If it's just one lens, don't worry about it, lenses back then were pretty roughly made. Shouldn't matter since what decides the focus is how far the rear housing of the lens is to the sensor.

03-10-2009, 07:02 AM   #5
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QuoteOriginally posted by cdm807 Quote
Help! I haven't done much real photography since my days with Pentax Spotmatic (mid-1970s). Recently upgraded to 100D, and trying to use by old SMC Takumar lenses.

1. I have a Pentax adapter, but lenses do not seem to attach so that aperture scale is square to top of camera (so reading is off center). Seems like this means that full focus range is compromised. Correct? Any suggestions?
When you consider that the built-in flash is in the way, this is actually a feature rather than a bug. It is normal and nothing to worry about.

QuoteQuote:
2. I can't seem to get an EV reading (in Manual mode) when I set aperature at f-stop desired and use e-dial to change shutter speed. What am I doing incorrectly?
Shoot in Av mode with the lens stopped down and your shutter speed will be set for you.

Or you can go the more involved route of shooting in M mode with the lens stopped down and pressing the AE-L button to set shutter speed. I always found that awkward and a needless waste of time and battery power when Av mode will do it for you automatically and continuously.
03-10-2009, 07:50 AM   #6
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QuoteOriginally posted by cdm807 Quote
1. I have a Pentax adapter, but lenses do not seem to attach so that aperture scale is square to top of camera (so reading is off center). Seems like this means that full focus range is compromised. Correct? Any suggestions?
Yes, I think this is normal as well--I have genuine adapter and see the same thing. I think the distance involved with a small fraction of a turn here is inconsequential.

QuoteOriginally posted by cdm807 Quote
2. I can't seem to get an EV reading (in Manual mode) when I set aperature at f-stop desired and use e-dial to change shutter speed. What am I doing incorrectly?
Mike mentioned the Av and AE-L (Hypermanual) methods. The third method is to enable optical depth-of-field preview via custom settings (I believe K100D is set to digital preview out of the box?). This will activate the meter in the manner you describe. With K/M glass, the lens will automatically stop down when you press AE-L or optical DoF preview--but with M42 you need to stop the lens down yourself.
03-10-2009, 07:23 PM   #7
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QuoteOriginally posted by Mike Cash Quote
When you consider that the built-in flash is in the way, this is actually a feature rather than a bug. It is normal and nothing to worry about.



Shoot in Av mode with the lens stopped down and your shutter speed will be set for you.

Or you can go the more involved route of shooting in M mode with the lens stopped down and pressing the AE-L button to set shutter speed. I always found that awkward and a needless waste of time and battery power when Av mode will do it for you automatically and continuously.
with one exception: i shoot on a tripod a lot, and prefer m mode with all lenses (especially when using auto braketing for exposure blending purposes). that is because, in the conditions i tend to shoot, the camera will get the exposure terribly wrong if the eyepiece is not covered by my eye (dear pentax, how about a small eyepiece shutter, activated automatically in conditions where it is rellevant, or manually when the user chooses; us landscape photographers will love you for it, and, not to forget, the damn dark frame substraction user slectable on k20d </rant>)
03-10-2009, 08:15 PM   #8
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QuoteOriginally posted by cdm807 Quote

1. I have a Pentax adapter, but lenses do not seem to attach so that aperture scale is square to top of camera (so reading is off center). Seems like this means that full focus range is compromised. Correct? Any suggestions?
This is not an issue as long as the base of the lens is snug against the adapter flange. Very few M42 lenses align vertical when used with the adapter. In fact, it is not unusual for a lens to not align vertical on a M42 body.

QuoteOriginally posted by cdm807 Quote

2. I can't seem to get an EV reading (in Manual mode) when I set aperature at f-stop desired and use e-dial to change shutter speed. What am I doing incorrectly?
As mentioned above, you need to turn the meter on to meter in M mode.

While you can work in M mode, it is much preferable to use Av mode. Either way, you are using classic stop-down metering the same as on the Spotmatic except that you don't have auto-aperture with the adapter. Remember to slide the len's Auto/Manual switch to the manual position. Nanok's comment regarding stray light through the viewfinder is very well taken. Stray light from the viewfinder can bias the exposure by several stops when a M42 lens is stopped down.

Steve

03-11-2009, 04:19 AM   #9
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QuoteOriginally posted by nanok Quote
with one exception: i shoot on a tripod a lot, and prefer m mode with all lenses (especially when using auto braketing for exposure blending purposes). that is because, in the conditions i tend to shoot, the camera will get the exposure terribly wrong if the eyepiece is not covered by my eye (dear pentax, how about a small eyepiece shutter, activated automatically in conditions where it is rellevant, or manually when the user chooses; us landscape photographers will love you for it, and, not to forget, the damn dark frame substraction user slectable on k20d </rant>)
My simple solution in those situations is to place my left thumb across the viewfinder when I press the button to meter. Works great and I have yet to misplace or lose my thumb.

The wonderful old Spotmatic ESII actually has a built-in viewfinder blind that swings into position when a certain position is selected on the shutter speed dial. Makes it a wonderful camera for the type of situations you describe. I have often wondered why this never became a standard feature.
03-11-2009, 05:34 AM   #10
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Thanks for all comments -- as a new member, I've learned a lot from this and other threads!
03-11-2009, 05:41 PM   #11
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QuoteOriginally posted by Mike Cash Quote
My simple solution in those situations is to place my left thumb across the viewfinder when I press the button to meter. Works great and I have yet to misplace or lose my thumb.

The wonderful old Spotmatic ESII actually has a built-in viewfinder blind that swings into position when a certain position is selected on the shutter speed dial. Makes it a wonderful camera for the type of situations you describe. I have often wondered why this never became a standard feature.
yes, it does work great, but only if you are using "one time metering" as mentioned, in M mode. if using Av mode, the camera will meter continuously, which means the eyecap must be covered at least while the shutter is closed (not taking a picture), and that's a major pita. but m mode works fine, that's why i mentioned it here (though it is slightly offtopic), somebody may find it useful.
03-12-2009, 05:05 AM   #12
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Perhaps I didn't understand well enough. When shooting on a tripod I always switch to M mode.
03-12-2009, 02:53 PM   #13
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QuoteOriginally posted by Mike Cash Quote
Perhaps I didn't understand well enough. When shooting on a tripod I always switch to M mode.
that's precisely what i do, and was pointing out , we are both saying the same thing.

one interesting thought, for pentax, just came to mind: how about detecting that the camera is on a tripod, and switching to a customizable "tripod shooting" mode (that would not work for me though, as my QR table is always on my camera, and i see no simple practical way to detect except a switch or contact in the tripod mounting hole), or how about designing a customizable mode for tripod shooting on the mode dial.. as i write this, i realized i was about to propose the (existing) "user" mode .. i have to look into that and see if it offers everything needed.

--
nanok_going_back_to_rtfm
03-13-2009, 02:07 AM   #14
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I always use the two second delay. I believe that automatically cancels SR, even if the SR switch is still in the active position.
03-13-2009, 05:06 PM   #15
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correct, i have noticed that too on the k20d at least. that's a very thoughtfull little detail. very pentax of them to think of that
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