Win a Pentax Limited Lens: Raffle Now Live!

zorza · 12-01-2013, 04:02 PM

This has hapenned to me some times before, but I now have saved th epictures to get a second opinion..

The 2 pictures where taken at the same time, in the same second, whitout changing any setting on the camera. There where no chabges in the lighting in the room. So, if nothing changed, if I did not change anything on the camera, and you can check the settings are the same, why is one picture so dark???

Attached Images

View Picture EXIF

View Picture EXIF

Na Horuk · 12-01-2013, 04:10 PM

Probably one of these:
1) You have spot metering enabled - the camera will underexpose if it meters on the white wall and overexpose if it meters on the black clothes. Since both of those things are very near the centre, a slight movement of the frame can dramatically change the metering. This can be remedied by using matrix metering or possibly even center weighted.
2) Your lens might have a problem with aperture blades (this one seems likely, especially if you are using an older manual lens) Might be sticky aperture blades
3) You took one photo before the meter actually took the measurement and then the second photo after it took measurement and adjusted the settings
4) Digital can be a bit unreliable and sometimes make decisions that we humans don't understand

**RobA_Oz** · 12-01-2013, 04:26 PM

Originally posted by Na Horuk

Probably one of these:
1) You have spot metering enabled - the camera will underexpose if it meters on the white wall and overexpose if it meters on the black clothes. Since both of those things are very near the centre, a slight movement of the frame can dramatically change the metering. This can be remedied by using matrix metering or possibly even center weighted.
2) Your lens might have a problem with aperture blades (this one seems likely, especially if you are using an older manual lens) Might be sticky aperture blades
3) You took one photo before the meter actually took the measurement and then the second photo after it took measurement and adjusted the settings
4) Digital can be a bit unreliable and sometimes make decisions that we humans don't understand

The EXIF says the lens was a DA*55, so no.2 is unlikely.

Were you using AE?

elliott · 12-01-2013, 04:29 PM

Can't be a metering issue since the shutter speed, aperture and ISO were all supposedly the same and the camera was in manual mode.

I would think sticky aperture blades if the problem was the opposite, overexposure when you were supposedly at a small aperture. With an f1.4 lens at f1.4 lens they shouldn't be moving. The blades usually stick when closing.

The problem could still be aperture related though, has this ever happened with other lenses?

zorza · 12-01-2013, 04:30 PM

Originally posted by Na Horuk

Probably one of these:
1) You have spot metering enabled - the camera will underexpose if it meters on the white wall and overexpose if it meters on the black clothes. Since both of those things are very near the centre, a slight movement of the frame can dramatically change the metering. This can be remedied by using matrix metering or possibly even center weighted.
2) Your lens might have a problem with aperture blades (this one seems likely, especially if you are using an older manual lens) Might be sticky aperture blades
3) You took one photo before the meter actually took the measurement and then the second photo after it took measurement and adjusted the settings
4) Digital can be a bit unreliable and sometimes make decisions that we humans don't understand

1) meetring is in center weight, not spot.
2) I am using s 55mm da* . BOth pictures taken at f1.4
3)Never thought that could be possible to happen, How can the camera fire without knowing how to fire?
4) I think this will be it

zorza · 12-01-2013, 04:35 PM

Just checked the lightroom catalog to look, and the same has happened with the 18-135 WR lens also.
Funny that the first picture is always the darkest...

And if the camera is shooting without knowing the correct exposure, sometimes it could overexpose the first and not underexpose.

CAn it be a camera thing??

Zorza

ps. thank to all for your inputs..

elliott · 12-01-2013, 04:42 PM

What do you mean by the first shot? First shot in the succession? First shot when turning the camera on? First shot after mounting the lens?

SpecialK · 12-01-2013, 04:45 PM

It has happened on rare occasions to me with the K-20, and perhaps the K-5 (which finally died with a bad mirror box motor). It is the camera body. The metering method would not stuff it up that bad. (Edit: Last night the dark frame looked black, now I see a little detail...)

ScooterMaxi Jim · 12-01-2013, 05:53 PM

I don't recall doing this, but after checking for a similar situation (but not so extreme), I had noticed that the frame shooting control had slipped over to bracketing. Possibly I had overshot 'Single Shot' and went all the way to the other end of the list without noticing it. If your bracketing setting happens to be set extremely wide, that would be the result.

mee · 12-01-2013, 06:06 PM

I was thinking something similar.. one is horribly underexposed, the other is a bit over exposed.. the camera is trying to set you with some 2 image HDR photos!

Closer to serious.. your settings are identical.. I suspect something flaky with the hardware (camera body) is happening.. it could be one of a number of things.. but likely (at least imo) hardware related..

ultraviolet · 12-01-2013, 06:08 PM

Was the room light from a fluorescent bulb? If it is, then check this out.
The Feral Photographer: Photographing under fluorescent lights

elliott · 12-01-2013, 06:14 PM

Originally posted by ultraviolet

Was the room light from a fluorescent bulb? If it is, then check this out.
The Feral Photographer: Photographing under fluorescent lights

At 1/30s that isn't a problem, even in a 50hz country he is capturing more than once cycle.

My money is on an aperture control problem of some form.

adwb · 12-02-2013, 01:25 AM

It need to go in for repair facility, problem is that it,s intermittent so I bet they won't get it to happen and send it back the same , with fault not found in the report.

Your first option is to keep the images every time it happens and print outer exif date for them, once you have decent evidence you could try sending it in, or better discuss it with them first.

The other option is use it till it fails or becomes a regular fault they find at the repair facility.

OldNoob · 12-02-2013, 05:01 AM

Might be your Aperture drive motor in your k-30

You Tube

Na Horuk · 12-02-2013, 06:55 AM

Oh, for some reason the aperture value wasn't shown when I checked the exif with my browser addon, thats why I assumed it was an older manual lens.
This really is odd, since they were taken at f1.4, so the aperture shouldn't be moving at all, which kind of rules out aperture problems. And you ruled out different metering, since you were using M mode. So it would have to be shutter lagging or the camera doing something with ISO/post processing. When you take these photos, can you maybe hear the shutter being different? Like, if one exposure is longer than the other, or if the motor/mirror sounds odd?

Were you maybe taking these photos in live view?

12-01-2013, 04:45 PM	#8
SpecialK Pentaxian Join Date: Dec 2006 Location: So California Photos: Gallery Posts: 16,482	It has happened on rare occasions to me with the K-20, and perhaps the K-5 (which finally died with a bad mirror box motor). It is the camera body. The metering method would not stuff it up that bad. (Edit: Last night the dark frame looked black, now I see a little detail...) Last edited by SpecialK; 12-02-2013 at 07:12 AM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
K-7 Manual Mode... What the hell just happened?	Student	Troubleshooting and Beginner Help	30	01-09-2011 01:15 PM
What the hell is 18-55mm?	Lzel	Troubleshooting and Beginner Help	11	12-05-2010 10:33 AM
What the hell?	axl	Pentax SLR Lens Discussion	8	12-31-2009 07:24 PM
What the hell is that	oatman911	Pentax DSLR Discussion	6	01-26-2009 09:15 PM
What the hell? (eBay Madness)	carpents	Pentax SLR Lens Discussion	5	01-11-2007 06:56 PM

12-01-2013, 04:10 PM	#2
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Probably one of these: 1) You have spot metering enabled - the camera will underexpose if it meters on the white wall and overexpose if it meters on the black clothes. Since both of those things are very near the centre, a slight movement of the frame can dramatically change the metering. This can be remedied by using matrix metering or possibly even center weighted. 2) Your lens might have a problem with aperture blades (this one seems likely, especially if you are using an older manual lens) Might be sticky aperture blades 3) You took one photo before the meter actually took the measurement and then the second photo after it took measurement and adjusted the settings 4) Digital can be a bit unreliable and sometimes make decisions that we humans don't understand

12-01-2013, 04:26 PM	#3
RobA_Oz Site Supporter Join Date: Nov 2008 Location: Tasmania, Australia Photos: Gallery Posts: 8,209	Originally posted by Na Horuk Probably one of these: 1) You have spot metering enabled - the camera will underexpose if it meters on the white wall and overexpose if it meters on the black clothes. Since both of those things are very near the centre, a slight movement of the frame can dramatically change the metering. This can be remedied by using matrix metering or possibly even center weighted. 2) Your lens might have a problem with aperture blades (this one seems likely, especially if you are using an older manual lens) Might be sticky aperture blades 3) You took one photo before the meter actually took the measurement and then the second photo after it took measurement and adjusted the settings 4) Digital can be a bit unreliable and sometimes make decisions that we humans don't understand The EXIF says the lens was a DA*55, so no.2 is unlikely. Were you using AE?

12-01-2013, 04:29 PM	#4
elliott Inactive Account Join Date: Dec 2008 Location: North Carolina Photos: Albums Posts: 1,720	Can't be a metering issue since the shutter speed, aperture and ISO were all supposedly the same and the camera was in manual mode. I would think sticky aperture blades if the problem was the opposite, overexposure when you were supposedly at a small aperture. With an f1.4 lens at f1.4 lens they shouldn't be moving. The blades usually stick when closing. The problem could still be aperture related though, has this ever happened with other lenses?

12-01-2013, 04:30 PM	#5
zorza Forum Member Join Date: Oct 2012 Posts: 50 Original Poster	Originally posted by Na Horuk Probably one of these: 1) You have spot metering enabled - the camera will underexpose if it meters on the white wall and overexpose if it meters on the black clothes. Since both of those things are very near the centre, a slight movement of the frame can dramatically change the metering. This can be remedied by using matrix metering or possibly even center weighted. 2) Your lens might have a problem with aperture blades (this one seems likely, especially if you are using an older manual lens) Might be sticky aperture blades 3) You took one photo before the meter actually took the measurement and then the second photo after it took measurement and adjusted the settings 4) Digital can be a bit unreliable and sometimes make decisions that we humans don't understand 1) meetring is in center weight, not spot. 2) I am using s 55mm da* . BOth pictures taken at f1.4 3)Never thought that could be possible to happen, How can the camera fire without knowing how to fire? 4) I think this will be it

12-01-2013, 04:35 PM	#6
zorza Forum Member Join Date: Oct 2012 Posts: 50 Original Poster	Just checked the lightroom catalog to look, and the same has happened with the 18-135 WR lens also. Funny that the first picture is always the darkest... And if the camera is shooting without knowing the correct exposure, sometimes it could overexpose the first and not underexpose. CAn it be a camera thing?? Zorza ps. thank to all for your inputs..

12-01-2013, 04:42 PM	#7
elliott Inactive Account Join Date: Dec 2008 Location: North Carolina Photos: Albums Posts: 1,720	What do you mean by the first shot? First shot in the succession? First shot when turning the camera on? First shot after mounting the lens?

12-01-2013, 05:53 PM	#9
ScooterMaxi Jim Veteran Member Join Date: Jul 2009 Location: Minnesota Posts: 1,520	I don't recall doing this, but after checking for a similar situation (but not so extreme), I had noticed that the frame shooting control had slipped over to bracketing. Possibly I had overshot 'Single Shot' and went all the way to the other end of the list without noticing it. If your bracketing setting happens to be set extremely wide, that would be the result.

12-01-2013, 06:06 PM	#10
mee Veteran Member Join Date: May 2010 Posts: 7,403	I was thinking something similar.. one is horribly underexposed, the other is a bit over exposed.. the camera is trying to set you with some 2 image HDR photos! Closer to serious.. your settings are identical.. I suspect something flaky with the hardware (camera body) is happening.. it could be one of a number of things.. but likely (at least imo) hardware related..

12-01-2013, 06:08 PM	#11
ultraviolet Pentaxian Join Date: May 2010 Photos: Albums Posts: 687	Was the room light from a fluorescent bulb? If it is, then check this out. The Feral Photographer: Photographing under fluorescent lights

12-01-2013, 06:14 PM	#12
elliott Inactive Account Join Date: Dec 2008 Location: North Carolina Photos: Albums Posts: 1,720	Originally posted by ultraviolet Was the room light from a fluorescent bulb? If it is, then check this out. The Feral Photographer: Photographing under fluorescent lights At 1/30s that isn't a problem, even in a 50hz country he is capturing more than once cycle. My money is on an aperture control problem of some form.

12-02-2013, 01:25 AM	#13
adwb Veteran Member Join Date: Sep 2009 Location: Bristol UK Photos: Gallery Posts: 1,636	It need to go in for repair facility, problem is that it,s intermittent so I bet they won't get it to happen and send it back the same , with fault not found in the report. Your first option is to keep the images every time it happens and print outer exif date for them, once you have decent evidence you could try sending it in, or better discuss it with them first. The other option is use it till it fails or becomes a regular fault they find at the repair facility.

12-02-2013, 06:55 AM	#15
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Oh, for some reason the aperture value wasn't shown when I checked the exif with my browser addon, thats why I assumed it was an older manual lens. This really is odd, since they were taken at f1.4, so the aperture shouldn't be moving at all, which kind of rules out aperture problems. And you ruled out different metering, since you were using M mode. So it would have to be shutter lagging or the camera doing something with ISO/post processing. When you take these photos, can you maybe hear the shutter being different? Like, if one exposure is longer than the other, or if the motor/mirror sounds odd? Were you maybe taking these photos in live view?

What the hell?

Win a Pentax Limited Lens: Raffle Now Live!