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06-18-2013, 02:04 PM   #1
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Possible Sensor Issues?

I've been lurking on this forum for a while, getting to know as I can about Pentax.

Recently I've come across an issue with my K01. Any pictures that I take come out to be so dark as to be unrecognizable as anything other than a black screen. I'm using an older M mount 50mm lens. On the first K01 I owned (RMA'd due to a sensor problem) it took wonderful photos. Now to take well lit indoor pictures at 800 ISO I have to turn the exposure up to almost 2".
Does this sound like a sensor problem leading to seriously dark pictures? Has anybody run across the same problem?

06-18-2013, 02:28 PM   #2
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doubt its your sensor, do you have it on manual mode? did you check your f-stop, and is it on something like f22 or f18. something tells me your just not familiar shooting in all manual mode. try the green button with your lens mounted, make sure the f-stop is turned all the way open, well at least to something like f8, and snap a pic and see if the green button picked up the right exposure, if it did you jus thave to learn to shoot in manual mode.
06-18-2013, 04:27 PM   #3
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Are you sure the aperture opens up when you take your pictures? Look in the lens when you take a picture to see what happens. For a 2 second exposure, you will see clearly if the aperture is open or stopped down some, or fully.

Hm, I wrote this a couple of hours ago, weird it didn't get posted :O I probably forgot to post it :P
06-18-2013, 08:13 PM   #4
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Thanks for the advice on checking to make sure the aperture is actually opening, seems silly to not have checked that earlier.
I'm new to the K01 but not so much to photography in general. My understanding is that with these older Pentax lenses on the K01 the aperture normally automatically opens to full, and that you can't actually control the aperture setting. Am I mistaken in that assumption? It seems like you can only change the exposure time with the dial and that there isn't a way to check what f-stop you're shooting at.

06-18-2013, 10:00 PM   #5
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with m lenses you have to set the aperture manually and than you can use the green button to get your exposure. you have to use it in manual mode also. I find M lenses a hassle, I prefer the takumars since your able to use aperture priority.
06-19-2013, 02:59 PM   #6
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I'll make a note to check out the Takumar lenses. It was indeed an issue of me having set the aperture ring to f/22. Being used to seeing a digital reminder on my old film Canon, I assumed that there would be something similar on the K01. On previous uses of my lens on the other camera I had just left it on f/2 and assumed that in M mode with old lenses it automatically shot wide open.
Thanks for the help guys! Hopefully I'll be able to make some more productive comments soon enough
06-19-2013, 10:52 PM   #7
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I sometimes do not fully mount the M50 f1.7 on K-01 and then the aperture ring can control the aperture in A-Mode.
You may try ... at your own risk ...!!
06-19-2013, 10:57 PM   #8
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Remove the aperture lever and it will act like a Takumar.

06-19-2013, 11:05 PM   #9
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QuoteOriginally posted by altopiet Quote
Remove the aperture lever and it will act like a Takumar.
I have thought about it ... Is it easy?
06-19-2013, 11:08 PM   #10
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dont remove it, I also forgot someone on the forum showed it before, some tape over the contacts on the mount will do the trick, you'll still have to set the aperture by itself but you dont have to worry about about it being stuck wide open and having to use the green button to meter.
06-19-2013, 11:48 PM   #11
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QuoteOriginally posted by SKwan Quote
I have thought about it ... Is it easy?
I've removed one from my Vivitar70-150, that was a reversible job. I removed the one from my Pentax M50/1.4, I had to cut it off as it wasn't attached with any screws. I haven't looked at the M50/1.7, as it's got a lens separation problem and is somewhere, waiting for spares, but I'm contemplating removing the one on the K35/3.5, but as I do not use it often, I haven't decided yet.
06-19-2013, 11:52 PM   #12
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QuoteOriginally posted by wanderography Quote
dont remove it, I also forgot someone on the forum showed it before, some tape over the contacts on the mount will do the trick, you'll still have to set the aperture by itself but you dont have to worry about about it being stuck wide open and having to use the green button to meter.
As far as I know it has nothing to do with the contacts, it is the aperture lever that is physically keeping the aperture open and forcing you to use the green button to stop down if using it at any other aperture than wide open.
06-20-2013, 12:20 AM   #13
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QuoteOriginally posted by altopiet Quote
As far as I know it has nothing to do with the contacts, it is the aperture lever that is physically keeping the aperture open and forcing you to use the green button to stop down if using it at any other aperture than wide open.
I can't find the post, but I'm pretty positive that you can cover the contacts to bypass the lever staying open, all K-mount lenses have an aperture lever, just the old ones M and down were are not chipped for the A mount cameras. I know for a fact someone on this forum knows what I'm talking about, they posted images on how to do it and everything.
06-20-2013, 02:17 AM   #14
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QuoteOriginally posted by wanderography Quote
I know for a fact someone on this forum knows what I'm talking about, they posted images on how to do it and everything.
That would be me, and that would be this (description on my flickr page):



Side note: A-series lenses weren't "chipped", as such - the seven contacts on the lens mount are just electrical connections. This was early 80s technology, when digital electronics were too bulky to fit inside a lens. Three of the conductive/insulated contacts are a binary code for the lens' widest aperture, three are the smallest aperture, and one retractable pin tells the body if the aperture is set to 'A'. The earlier K- and M-series lenses have one contact: the mount itself, which the body uses to tell if a K-mount lens is present, so that it opens the aperture all the way to provide more light for focusing (and thinner DoF, useful for focus peaking). The "tape hack" defeats this.
06-20-2013, 04:39 AM   #15
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QuoteOriginally posted by THoog Quote
That would be me, and that would be this (description on my flickr page):



Side note: A-series lenses weren't "chipped", as such - the seven contacts on the lens mount are just electrical connections. This was early 80s technology, when digital electronics were too bulky to fit inside a lens. Three of the conductive/insulated contacts are a binary code for the lens' widest aperture, three are the smallest aperture, and one retractable pin tells the body if the aperture is set to 'A'. The earlier K- and M-series lenses have one contact: the mount itself, which the body uses to tell if a K-mount lens is present, so that it opens the aperture all the way to provide more light for focusing (and thinner DoF, useful for focus peaking). The "tape hack" defeats this.
Thanks for the info, I know this is a K-01 thread, and the K-30 also have Auto ISO in M mode, however, have you tried this method on other models? I removed my aperture levers while my only DSLR was the K-x, no Auto ISO...
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