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03-23-2018, 08:04 PM   #1
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Hardware issue, or user error?

I have a K7, and I've just recently started setting it up outside as a camera trap. It's gotten wet and its gotten cold, so maybe that is a factor. I've had it out for a few days total, for a little over 24 hours at a time.


It caught one photo of the target (coyote) last night that was massively underexposed, and the camera never increased the ISO, so the photo was 8 seconds long, and even if I could have pushed it past barely visible, it would have been a lost shot anyway.


I was having some problems today, and I don't know if they were mine, or the camera's.


In Tv mode, I would set shutter speed, compose my photo, snap, and review it only to find the camera had changed it.
I don't think this is the correct behavior?


I don't think having a fully manual lens on the camera would impact this either? I got my first fully manual lens in the mail today and was trying it out, and running into this problem with Tv mode, as well as exposure issues. Well, I assumed the exposure issues were because there is some trick to metering with manual lenses (I remember reading about it, and was planning to look it up again, but I just tweaked the exposure compensation at the time so I could test the lens).

But then I set it up in the camera trap again with an FA lens, and it was underexposing by more than 5(!!!) stops.
This was at night, so perhaps metering just isn't reliable when it's that dark... I've only played with those sorts of shots occasionally, so I don't remember if this is normal behavior or not.
Tv mode was still acting up, possibly Tav as well, though I was more focused on just trying to get the exposure and focus right, than testing it.


The battery was old but fully charged (I only have one), and the camera was still warm from the house when I took it out. It is behaving normally other than metering and Tv retention. All the buttons were responsive, photo review was normal, displays show the settings correctly, etc


Last edited by Canid; 03-23-2018 at 08:26 PM.
03-23-2018, 10:06 PM   #2
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The first thing I would do is check the camera in M mode. Set the correct exposure manually and see if the image comes out right. Then, compare metering in live view versus viewfinder mode. Verify that you're using matrix metering rather than spot metering. Reset the camera settings if you continue experiencing issues.

Given the K-7's age, you may also need to replace the battery, especially if you're using it in cold conditions.

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03-23-2018, 10:16 PM   #3
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A lens with no A setting will only shoot wide open in all modes except M. The camera won't use matrix metering either - it'll switch to center weighted. And the metering wants you to press the green button anyway. The K-7 meter isn't as sensitive in the dark as later models - maybe down to Ev 0? So if it's really dark, the meter will be out of range and inaccurate. I think the meter would give you a reading, based on the lens being wide open. Whether that's close to accurate, I don't know.

The meter may not be that important at night, because the light won't change that much. So you could just set a high ISO, 1/60 and let the lens be wide open. You'd maybe get overexposure if the full moon came in and out behind clouds, but otherwise it would be OK. Since you wouldn't be doing anything automatically, M mode would work fine, and you could even set an aperture on the lens.

The FA lens should avoid some of those issues, so some other piece of the puzzle is missing.
03-23-2018, 10:48 PM   #4
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A non-"A" lens will also revert to Av mode except in M, B or X. A fully manual lens is not likely to be weather sealed either.

03-23-2018, 10:52 PM   #5
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The manual lens was the Laowa 15mm macro, so the aperture doesn't change when the shot is taken. Given that the camera is looking through the lens already stopped down, the metering should be correct, shouldn't it?

When would I use the green button, given that pressing it in most modes returns settings to program baseline?

What about the issues with Tv? Is there any circumstance where the camera is supposed to move the shutter speed from where the user put it while in Tv mode?

---------- Post added 03-24-18 at 01:55 AM ----------

Not A Number .... That answers my question. What about Tav though? Shouldn't that function normally with a manual lens?

---------- Post added 03-24-18 at 01:59 AM ----------

Just1MoreDave, I do need the camera to adjust exposure, because the coyote comes by late at night and early in the morning, when there is significantly more light.
03-23-2018, 11:57 PM   #6
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QuoteOriginally posted by Canid Quote
The manual lens was the Laowa 15mm macro, so the aperture doesn't change when the shot is taken. Given that the camera is looking through the lens already stopped down, the metering should be correct, shouldn't it?
You will get automatic exposure only in Av mode.

QuoteOriginally posted by Canid Quote
When would I use the green button, given that pressing it in most modes returns settings to program baseline?
In M mode pressing the green button will give you metered shutter speed when used with a manual lens

QuoteOriginally posted by Canid Quote
What about the issues with Tv? Is there any circumstance where the camera is supposed to move the shutter speed from where the user put it while in Tv mode?
You cannot use Tv mode with that lens. The camera will revert to Av mode.

---------- Post added 03-24-18 at 06:59 AM ----------

QuoteOriginally posted by Canid Quote
What about Tav though? Shouldn't that function normally with a manual lens?
No, it will revert to Av mode. This is because the camera in TAv mode needs to know the shutter speed and aperture selected by the user. With a manual lens it does not know the aperture and therefore cannot function.

Last edited by pschlute; 03-24-2018 at 02:57 AM.
03-24-2018, 04:15 PM   #7
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Using a manual lens limits the camera's ability to make automatic adjustments to the exposure. You can set a particular shutter speed in M mode but you can't get any automatic exposure. All the other modes behave like Av with the lens wide open. The Laowa or an M42 lens would allow you to set a fixed aperture. You can use Auto ISO in Av mode, and the K-7 allows some control over how Auto ISO works. The first page of the menu has ISO Auto Settings where you can set a range for ISO and how quickly the camera raises ISO. If you make the upper limit 6400 and choose Fast, the camera might keep the shutter speed high enough to freeze motion. Then you'd get a shot. You might have to fool around with the ISO controls if the camera always jumps to 6400 even with some light, because 6400 sucks for quality.
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