What the hell?

IchabodCrane · 12-02-2013, 09:31 AM

Something is not right here. The EXIF claims f/1.4 but the second shot (the one we can actually see) sure looks like it has much greater DOF than f/1.4 would provide. Maybe clean the lens and body contacts and start over?

zorza · 12-02-2013, 10:30 AM

Thanks all for you guesses..

Well, it is not really the lens, as using my 18-135wr lens hs donne the same thing.

There is no change in the sound the camera does while taking the shots. One is not really any faster than the other, or at least something you could guess from hearing it...

I am thinking it mught be a problem with the body, but it is not everytime, and I never know when it will happen.
Will try with aa batteries, as these where all taken with the standard batery. I know it should not make a diference, but who knows? That's one more guess..

Tnaks

Zorza

lister6520 · 12-02-2013, 10:46 AM - **1 Like**

My guess is a problem with the lens iris or the lever in the camera that drives the iris. You mentioned that it happens also with another lens so that makes it unlikely to be the lens.

Although at first one would logically think that at full open aperture this couldn't be a problem on closer inspection it turns out that it can quite easily be so. Due to the way the K-30s shutter, mirror and iris are mechanically linked it has a rather odd sequence of events when it shoots.

As the mirror lifts the aperture lever is pushed to the full closed position and then released again before the first shutter curtain opens. If the lever is a bit sticky (or more often the lens iris) the lever might not move back quickly enough leaving a partially closed iris during the exposure.

Oldbayrunner · 12-02-2013, 01:43 PM

Not sure why the two came out differently but I do have a question regarding the exposure settings used. Was the room very dimly lit? Under proper exposure at F1.4 , 1/30 & 3200 ISO would be correct for an EV 1 factor (= dimly lit room properly exposed) The puzzling part to me in the exif is the 1.70 Bias exposure with those settings which would result in the highly clipped 2nd photo. The puzzling part is the two together look like the bias exposure would be as if one was a -1.70 and the other a +1.70 bias setting. Not saying that is what happened.

I agree with IcabodCrane also... For the the almost enitire body shot as it stands with the camera tilted in portrait with a 55mm lens you would need to be at least 15' from the subject. At that distance your depth of field would only be about 1.5ft with a near focus limit of slightly over 15.3 feet and a far focus limit of approx 16.7ft. the background shouldn't be that visable

Last edited by Oldbayrunner; 12-02-2013 at 02:06 PM.

zorza · 12-02-2013, 02:50 PM

Originally posted by Oldbayrunner

Not sure why the two came out differently but I do have a question regarding the exposure settings used. Was the room very dimly lit? Under proper exposure at F1.4 , 1/30 & 3200 ISO would be correct for an EV 1 factor (= dimly lit room properly exposed) The puzzling part to me in the exif is the 1.70 Bias exposure with those settings which would result in the highly clipped 2nd photo. The puzzling part is the two together look like the bias exposure would be as if one was a -1.70 and the other a +1.70 bias setting. Not saying that is what happened.

I agree with IcabodCrane also... For the the almost enitire body shot as it stands with the camera tilted in portrait with a 55mm lens you would need to be at least 15' from the subject. At that distance your depth of field would only be about 1.5ft with a near focus limit of slightly over 15.3 feet and a far focus limit of approx 16.7ft. the background shouldn't be that visable

So, I am starting to believe the problem lies in the body of the K-30.. .Anyone heard something like tis before??

The +1.7ev in because I always try to expose to the right. I might have had that setting on when taking the pictures, BUT, the setting would be the same for both pictures..
As for the background blur, I didn't make the math, but believing you are right, how can I defenetly test it?

Thanks

ps. thinking of giving th k30 to my girlfriendf and getting a k5II to me. The k-3 is a lot of money. For that, I can get a FF from another brand... The k-5II, is it worth the extra punch?? Priorities to me are:
Low light photography (indor and I hate flash)
af spped

lister6520 · 12-03-2013, 11:00 AM

"The k-3 is a lot of money. For that, I can get a FF from another brand.

Read more at: https://www.pentaxforums.com/forums/151-pentax-k-30-k-50/244196-what-hell-2.html#ixzz2mR5A7LKo"

I'm not so sure that a bottom of the range FF camera is necessarily any better or even nearly as good as a top of the range APS-C camera except possibly for some very specific types of photos.

Oldbayrunner · 12-03-2013, 11:43 AM

Originally posted by zorza

So, I am starting to believe the problem lies in the body of the K-30.. .Anyone heard something like tis before??

The +1.7ev in because I always try to expose to the right. I might have had that setting on when taking the pictures, BUT, the setting would be the same for both pictures..
As for the background blur, I didn't make the math, but believing you are right, how can I defenetly test it?

Thanks

af spped

A +1.7 bias exposure to the right with your exposure settings dead on the money will IMO give you a lot of clipped photos, especially if there is any light coming from windows etc near the subject and would be compounded possibly even more if your D range settings are set to auto or on.

My logic is telling me with the depth of field being off the aperture didn't open correctly for a 1.4 setting. Either the lens or the camera barely opened the aperture on the lens for the first photo but enough on the 2nd one to expose it but not completely enough for what should be the correct depth of field for a wide open shot.

In the old days that would be caused either by oil on the aperture blades or the spring for the aperture lever on the camera body weakening where it wouldn't open and close the blades properly for the selected aperture settings.

If it were me I would contact Pentax Service and talk to them about the problem and see what they advise.

altopiet · 12-12-2013, 12:48 AM

I had a similar problem 2 days ago with my K-30 (about 21000 clicks on it), and my brand new DA70mm 2.4

Taken within 2 secs...#2 kicked up the shutter speed to1/250, and dropped the ISO to 200...

bin · 12-12-2013, 01:35 AM

I know it's an unlikely cause, but what firmware are you running. Pentax will probably suggest upgrade to latest as a matter of routine anyway...... :-)

altopiet · 12-12-2013, 02:02 AM

Originally posted by bin

I know it's an unlikely cause, but what firmware are you running. Pentax will probably suggest upgrade to latest as a matter of routine anyway...... :-)

1.05, I updated the same day it was released, and haven't had any problems until now..

altopiet · 12-12-2013, 04:17 AM

Just to further confuse me, at the same event, a little earlier...
#1 @f2.4 and #2 @f2.8, but look at the shutter speed and ISO...the ISO was set on Auto...I wonder if that might have something to do with it. These were the only pics with exposure problems out of about 150 taken at the event. BTW all jpegs just re-sized, but the RAW images have the same problem

Oldbayrunner · 12-12-2013, 07:35 AM

It has nothing to do with your camera version update. It has to do with you and your use of your cameras auto metering plus maybe a couple other settings within your camera. Even though your camera has all of these wonderful auto adjustments, you as the photographer still need to assess the conditions you are in, meter what your trying to capture and insure your camera set up to expose the best for what your trying to capture or you will get varied results leaving you with some incorrectly exposed photos. Look at all of the varied lighting contrast that your camera could be adjusting on, the slightest camera movement on your part, even with your locking the aperture setting and the shutter release button depressed half way, your camera will still be changing what it is metering and vary the Shutter & ISO exposure settings right up until you release the shutter and expose the shot at whatever the metered settings were at that time. Allowing your camera's ability to do that will leave you with the varied exposure results in the manner you have shown. This is why AE Lock comes in handy. The rules of exposure haven't changed, you can't blame the camera for your not having it set and locked correctly for what it is you want it to do.

altopiet · 12-12-2013, 08:17 AM

Originally posted by Oldbayrunner

It has nothing to do with your camera version update. It has to do with you and your use of your cameras auto metering plus maybe a couple other settings within your camera. Even though your camera has all of these wonderful auto adjustments, you as the photographer still need to assess the conditions you are in, meter what your trying to capture and insure your camera set up to expose the best for what your trying to capture or you will get varied results leaving you with some incorrectly exposed photos. Look at all of the varied lighting contrast that your camera could be adjusting on, the slightest camera movement on your part, even with your locking the aperture setting and the shutter release button depressed half way, your camera will still be changing what it is metering and vary the Shutter & ISO exposure settings right up until you release the shutter and expose the shot at whatever the metered settings were at that time. Allowing your camera's ability to do that will leave you with the varied exposure results in the manner you have shown. This is why AE Lock comes in handy. The rules of exposure haven't changed, you can't blame the camera for your not having it set and locked correctly for what it is you want it to do.

If you look closely at the EXIF and photographs, you'll see that the 2 shots were taken from exactly the same position, virtually a second or 3 apart, with the same settings, center-weighted metering mode. As I've said in my previous post this is the first time I've experienced something like this in over 21000 clicks, with my K-30, and it is something I've never seen in over 50000 clicks with my K-x...If spot metering was involved I could understand it, but almost identical shots in center-weighted metering mode should not have such an effect when there is nothing that changes in the scene that could have such an effect on the exposure as far as I can see, or is it possible? A few months ago I shot about 5000 photographs in one day, with a different lens, and not once did anything like this occur...?

EDIT: Just to be more clear, the photographs in both sets, were consecutive, and there were about 80 or so other, perfectly exposed photographs between the two sets...

mrNewt · 12-12-2013, 08:26 AM

Umm... shoot in the dark and probably a miss, but... bracketing!?
Is there any chance you accidentally switch to braketing mode shooting!? And camera takes the pictures over and under exposed?

I know it usually takes 3 pictures instead of 2.. and the overexposure/underexposure is based on your settings... but what else could it be? Does it takes 3 pictures... do you have one perfectly exposed picture and then the over and under exposed?

From the pictures that's what it seems to be doing!?
I also remember you can set the order of the images when you bracket like under / normal / over OR under / over / normal. And seems like your camera is doing just that!?

Again, a lot of assumption, but based on the pictures, that's my only logical conclusion so far.

altopiet · 12-12-2013, 08:47 AM

Originally posted by mrNewt

Umm... shoot in the dark and probably a miss, but... bracketing!?
Is there any chance you accidentally switch to braketing mode shooting!? And camera takes the pictures over and under exposed?

I know it usually takes 3 pictures instead of 2.. and the overexposure/underexposure is based on your settings... but what else could it be? Does it takes 3 pictures... do you have one perfectly exposed picture and then the over and under exposed?

From the pictures that's what it seems to be doing!?
I also remember you can set the order of the images when you bracket like under / normal / over OR under / over / normal. And seems like your camera is doing just that!?

Again, a lot of assumption, but based on the pictures, that's my only logical conclusion so far.

I see what you're saying, but no.... single shot mode, not even continuous focusing. If you look at the first set you'll see where the person is hanging the ribbon, or what ever it's called, around my son's neck, it's impossible to have changed anything in that time frame, same with the second set, look at the lady heading to the same man.... I just pressed the shutter button, released and pressed again immediately..

12-12-2013, 08:17 AM	#28
altopiet Veteran Member Join Date: Sep 2010 Location: The Gem of the Karoo, South Africa Photos: Gallery \| Albums Posts: 2,307	Originally posted by Oldbayrunner It has nothing to do with your camera version update. It has to do with you and your use of your cameras auto metering plus maybe a couple other settings within your camera. Even though your camera has all of these wonderful auto adjustments, you as the photographer still need to assess the conditions you are in, meter what your trying to capture and insure your camera set up to expose the best for what your trying to capture or you will get varied results leaving you with some incorrectly exposed photos. Look at all of the varied lighting contrast that your camera could be adjusting on, the slightest camera movement on your part, even with your locking the aperture setting and the shutter release button depressed half way, your camera will still be changing what it is metering and vary the Shutter & ISO exposure settings right up until you release the shutter and expose the shot at whatever the metered settings were at that time. Allowing your camera's ability to do that will leave you with the varied exposure results in the manner you have shown. This is why AE Lock comes in handy. The rules of exposure haven't changed, you can't blame the camera for your not having it set and locked correctly for what it is you want it to do. If you look closely at the EXIF and photographs, you'll see that the 2 shots were taken from exactly the same position, virtually a second or 3 apart, with the same settings, center-weighted metering mode. As I've said in my previous post this is the first time I've experienced something like this in over 21000 clicks, with my K-30, and it is something I've never seen in over 50000 clicks with my K-x...If spot metering was involved I could understand it, but almost identical shots in center-weighted metering mode should not have such an effect when there is nothing that changes in the scene that could have such an effect on the exposure as far as I can see, or is it possible? A few months ago I shot about 5000 photographs in one day, with a different lens, and not once did anything like this occur...? EDIT: Just to be more clear, the photographs in both sets, were consecutive, and there were about 80 or so other, perfectly exposed photographs between the two sets... Last edited by altopiet; 12-12-2013 at 08:29 AM.

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12-02-2013, 09:31 AM	#16
IchabodCrane Veteran Member Join Date: Sep 2012 Photos: Gallery \| Albums Posts: 1,728	Something is not right here. The EXIF claims f/1.4 but the second shot (the one we can actually see) sure looks like it has much greater DOF than f/1.4 would provide. Maybe clean the lens and body contacts and start over?

12-02-2013, 10:30 AM	#17
zorza Forum Member Join Date: Oct 2012 Posts: 50 Original Poster	Thanks all for you guesses.. Well, it is not really the lens, as using my 18-135wr lens hs donne the same thing. There is no change in the sound the camera does while taking the shots. One is not really any faster than the other, or at least something you could guess from hearing it... I am thinking it mught be a problem with the body, but it is not everytime, and I never know when it will happen. Will try with aa batteries, as these where all taken with the standard batery. I know it should not make a diference, but who knows? That's one more guess.. Tnaks Zorza

12-02-2013, 10:46 AM - 1 Like	#18
lister6520 Veteran Member Join Date: May 2012 Posts: 733	My guess is a problem with the lens iris or the lever in the camera that drives the iris. You mentioned that it happens also with another lens so that makes it unlikely to be the lens. Although at first one would logically think that at full open aperture this couldn't be a problem on closer inspection it turns out that it can quite easily be so. Due to the way the K-30s shutter, mirror and iris are mechanically linked it has a rather odd sequence of events when it shoots. As the mirror lifts the aperture lever is pushed to the full closed position and then released again before the first shutter curtain opens. If the lever is a bit sticky (or more often the lens iris) the lever might not move back quickly enough leaving a partially closed iris during the exposure.

12-02-2013, 01:43 PM	#19
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Not sure why the two came out differently but I do have a question regarding the exposure settings used. Was the room very dimly lit? Under proper exposure at F1.4 , 1/30 & 3200 ISO would be correct for an EV 1 factor (= dimly lit room properly exposed) The puzzling part to me in the exif is the 1.70 Bias exposure with those settings which would result in the highly clipped 2nd photo. The puzzling part is the two together look like the bias exposure would be as if one was a -1.70 and the other a +1.70 bias setting. Not saying that is what happened. I agree with IcabodCrane also... For the the almost enitire body shot as it stands with the camera tilted in portrait with a 55mm lens you would need to be at least 15' from the subject. At that distance your depth of field would only be about 1.5ft with a near focus limit of slightly over 15.3 feet and a far focus limit of approx 16.7ft. the background shouldn't be that visable Last edited by Oldbayrunner; 12-02-2013 at 02:06 PM.

12-02-2013, 02:50 PM	#20
zorza Forum Member Join Date: Oct 2012 Posts: 50 Original Poster	Originally posted by Oldbayrunner Not sure why the two came out differently but I do have a question regarding the exposure settings used. Was the room very dimly lit? Under proper exposure at F1.4 , 1/30 & 3200 ISO would be correct for an EV 1 factor (= dimly lit room properly exposed) The puzzling part to me in the exif is the 1.70 Bias exposure with those settings which would result in the highly clipped 2nd photo. The puzzling part is the two together look like the bias exposure would be as if one was a -1.70 and the other a +1.70 bias setting. Not saying that is what happened. I agree with IcabodCrane also... For the the almost enitire body shot as it stands with the camera tilted in portrait with a 55mm lens you would need to be at least 15' from the subject. At that distance your depth of field would only be about 1.5ft with a near focus limit of slightly over 15.3 feet and a far focus limit of approx 16.7ft. the background shouldn't be that visable So, I am starting to believe the problem lies in the body of the K-30.. .Anyone heard something like tis before?? The +1.7ev in because I always try to expose to the right. I might have had that setting on when taking the pictures, BUT, the setting would be the same for both pictures.. As for the background blur, I didn't make the math, but believing you are right, how can I defenetly test it? Thanks ps. thinking of giving th k30 to my girlfriendf and getting a k5II to me. The k-3 is a lot of money. For that, I can get a FF from another brand... The k-5II, is it worth the extra punch?? Priorities to me are: Low light photography (indor and I hate flash) af spped

12-03-2013, 11:00 AM	#21
lister6520 Veteran Member Join Date: May 2012 Posts: 733	"The k-3 is a lot of money. For that, I can get a FF from another brand. Read more at: https://www.pentaxforums.com/forums/151-pentax-k-30-k-50/244196-what-hell-2.html#ixzz2mR5A7LKo" I'm not so sure that a bottom of the range FF camera is necessarily any better or even nearly as good as a top of the range APS-C camera except possibly for some very specific types of photos.

12-03-2013, 11:43 AM	#22
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Originally posted by zorza So, I am starting to believe the problem lies in the body of the K-30.. .Anyone heard something like tis before?? The +1.7ev in because I always try to expose to the right. I might have had that setting on when taking the pictures, BUT, the setting would be the same for both pictures.. As for the background blur, I didn't make the math, but believing you are right, how can I defenetly test it? Thanks af spped A +1.7 bias exposure to the right with your exposure settings dead on the money will IMO give you a lot of clipped photos, especially if there is any light coming from windows etc near the subject and would be compounded possibly even more if your D range settings are set to auto or on. My logic is telling me with the depth of field being off the aperture didn't open correctly for a 1.4 setting. Either the lens or the camera barely opened the aperture on the lens for the first photo but enough on the 2nd one to expose it but not completely enough for what should be the correct depth of field for a wide open shot. In the old days that would be caused either by oil on the aperture blades or the spring for the aperture lever on the camera body weakening where it wouldn't open and close the blades properly for the selected aperture settings. If it were me I would contact Pentax Service and talk to them about the problem and see what they advise.

12-12-2013, 01:35 AM	#24
bin New Member Join Date: Dec 2013 Location: Wiltshire UK Posts: 7	I know it's an unlikely cause, but what firmware are you running. Pentax will probably suggest upgrade to latest as a matter of routine anyway...... :-)

12-12-2013, 02:02 AM	#25
altopiet Veteran Member Join Date: Sep 2010 Location: The Gem of the Karoo, South Africa Photos: Gallery \| Albums Posts: 2,307	Originally posted by bin I know it's an unlikely cause, but what firmware are you running. Pentax will probably suggest upgrade to latest as a matter of routine anyway...... :-) 1.05, I updated the same day it was released, and haven't had any problems until now..

12-12-2013, 07:35 AM	#27
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	It has nothing to do with your camera version update. It has to do with you and your use of your cameras auto metering plus maybe a couple other settings within your camera. Even though your camera has all of these wonderful auto adjustments, you as the photographer still need to assess the conditions you are in, meter what your trying to capture and insure your camera set up to expose the best for what your trying to capture or you will get varied results leaving you with some incorrectly exposed photos. Look at all of the varied lighting contrast that your camera could be adjusting on, the slightest camera movement on your part, even with your locking the aperture setting and the shutter release button depressed half way, your camera will still be changing what it is metering and vary the Shutter & ISO exposure settings right up until you release the shutter and expose the shot at whatever the metered settings were at that time. Allowing your camera's ability to do that will leave you with the varied exposure results in the manner you have shown. This is why AE Lock comes in handy. The rules of exposure haven't changed, you can't blame the camera for your not having it set and locked correctly for what it is you want it to do.

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12-12-2013, 08:26 AM	#29
mrNewt Veteran Member Join Date: Nov 2011 Location: ON, RH Posts: 2,181	Umm... shoot in the dark and probably a miss, but... bracketing!? Is there any chance you accidentally switch to braketing mode shooting!? And camera takes the pictures over and under exposed? I know it usually takes 3 pictures instead of 2.. and the overexposure/underexposure is based on your settings... but what else could it be? Does it takes 3 pictures... do you have one perfectly exposed picture and then the over and under exposed? From the pictures that's what it seems to be doing!? I also remember you can set the order of the images when you bracket like under / normal / over OR under / over / normal. And seems like your camera is doing just that!? Again, a lot of assumption, but based on the pictures, that's my only logical conclusion so far.

12-12-2013, 08:47 AM	#30
altopiet Veteran Member Join Date: Sep 2010 Location: The Gem of the Karoo, South Africa Photos: Gallery \| Albums Posts: 2,307	Originally posted by mrNewt Umm... shoot in the dark and probably a miss, but... bracketing!? Is there any chance you accidentally switch to braketing mode shooting!? And camera takes the pictures over and under exposed? I know it usually takes 3 pictures instead of 2.. and the overexposure/underexposure is based on your settings... but what else could it be? Does it takes 3 pictures... do you have one perfectly exposed picture and then the over and under exposed? From the pictures that's what it seems to be doing!? I also remember you can set the order of the images when you bracket like under / normal / over OR under / over / normal. And seems like your camera is doing just that!? Again, a lot of assumption, but based on the pictures, that's my only logical conclusion so far. I see what you're saying, but no.... single shot mode, not even continuous focusing. If you look at the first set you'll see where the person is hanging the ribbon, or what ever it's called, around my son's neck, it's impossible to have changed anything in that time frame, same with the second set, look at the lady heading to the same man.... I just pressed the shutter button, released and pressed again immediately..