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06-27-2014, 04:51 PM   #1
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Could this be a Camera Issue or Lens Issue?

Everything is the same in the exif, but photos in sequence progressively get overexposed. Is this a lens or camera problem? It was set to spot, but would it fluctuate that much? This is pretty drastic. This doesn't exhibit the same problem with other lenses.


Last edited by dcpropilot; 07-31-2014 at 08:11 AM.
06-27-2014, 04:55 PM   #2
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This could be caused by sticky aperture blades on your lens. Try another lens and see if you can reproduce the issue. If not, look at the front of your 40mm while shooting (and set the camera to a slow shutter speed) and check to see if it stops down all the way. You can also check for sticky aperture blades by removing the lens and closing the aperture blades using the lever. If the blades don't open smoothly, or if they don't snap back quickly when you let go of the lens, there's something wrong with the lens.

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06-27-2014, 05:10 PM   #3
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Since it happens with different lens I would assume that rules out lens issues.

Two other possibilities are: since you are using spot metering yes that can cause dramatic differences sometimes. Try the same test in matrix mode to eliminate that. And check to see if you have the camera in exposure bracketing mode.
06-27-2014, 05:11 PM   #4
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Thanks, I'll try the things you mentioned. Also, for some reason, in lower light situations, I can keep the EV set to zero. In many cases, as soon as brighter light is introduced, I have to set EV to -.3 to -2.0. Frustrating!! Almost like shooting with a manual exposure lens.

---------- Post added 06-27-2014 at 08:19 PM ----------

On the K-30, I have multi-segment, center weighter, and spot. I just now changed it to multi-segment (would this be considered the matrix mode on the K-30?) Should I also link the exposure and focus point (the description of this function in the menu is "Exposure is biased for the focal point when using multi-segmented metering.")?

06-27-2014, 06:07 PM   #5
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For testing purposes set it to center weighted don't worry about linking exposure to focus point. Try a series of images shooting the same subject. If possible on a tripod to avoid any movement.

Make sure your EV comp is at zero, flash off, put it in Av mode. Check the drive mode button and make sure it is in single exposure not bracketing. I don't think it is bracketing as the EXIF would change if it were but you should check.

I'm hoping it is spot exposure mode because I don't know what else it would be. If this was only happening on one lens then I would agree with Adam it sounds just like sticking aperture blades. Are you sure you can duplicate the issue with multiple lenses?
06-27-2014, 06:09 PM   #6
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I'm thinking bracket mode is on. I thought wrong...as not all lenses are doing it...

This still applies ---> My opinion on spot metering - it should only be used if you know how to use it, and if you do, then you don't need it.

Last edited by SpecialK; 06-28-2014 at 01:16 PM.
06-27-2014, 06:22 PM   #7
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I'm with SpecialK....You have bracket mode turned on. Press the right 4-way button (the one with the little clock looking thing on it), and select "single frame shooting", should fix the problem.
06-27-2014, 06:26 PM   #8
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Hmmm, it was definitely not on bracketing mode...it was set to single frame. This is the only lens that is having this issue...
I tried to take a look inside the front of the lens while shooting...but couldn't see the blades. I'll try it again to see if I can get a glimpse.. I'll also try the things that jatrax mentioned.
Thanks everyone for your help! I'll report back on what I find.


Last edited by dcpropilot; 06-27-2014 at 06:32 PM.
06-27-2014, 06:28 PM   #9
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I thing the blazing sunshine of that beautiful smile is causing overexposure.

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06-27-2014, 06:33 PM   #10
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The EXIF data shows no EV bias. Wouldn't this change in bracketing mode? The EXIF is also showing the same f-stop and shutter speed for all three photos.
06-27-2014, 06:47 PM   #11
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QuoteOriginally posted by dcpropilot Quote
This is the only lens that is having this issue...
Hold up, I initially read your post to say you were having the same issue with different lenses. I just looked back and reread and it says the opposite. So if this lens is the only lens that has the problem then the answer is simple: you have sticking aperture blades, just like Adam noted way up above. What happens is that the aperture blades do not fully close during the exposure causing over-exposure. But the EXIF records the same because the camera thinks the blades did close properly.

Set your aperture to f/16 look in the front of the lens and take a shot. The blades should close almost completely. Your issue is intermittent so you might have to take several shots to see what happens. If the blades are not closing almost all the way at f/16 then they are sticking. Try the same thing with a different (known good) lens to see what I mean.
06-27-2014, 07:02 PM   #12
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Originally when I tried to see the blades, I had it at wide open so I guess this explains why I couldn't see them. I now set it to 16 and I can definitely see the blades closing...and everything seems to be fine and doesn't appear to be sticking, (unless the problem is intermittent). The blades close slightly when pressing half shutter press, I assume this is normal. What I can't grasp is why EV zero is fine for indoors and then as soon as I go outside I really have to apply some heavy negative EV on many shots.
06-27-2014, 09:28 PM   #13
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QuoteOriginally posted by dcpropilot Quote
(unless the problem is intermittent)
The problem is intermittent. Look at your sample images. Those should all be identical. If the blades are working now then you should be able to take 5 shots of the same thing and get identical results.
QuoteOriginally posted by dcpropilot Quote
What I can't grasp is why EV zero is fine for indoors and then as soon as I go outside I really have to apply some heavy negative EV on many shots.
Possibly because it is brighter outside? If you are shooting wide open or nearly so inside then the sticking blades are not an issue, they are not stopping down anyway. When you go outside and use a smaller aperture f/8 for example then the blades need to close down to achieve that but when they stick they cannot so stay wider open than they should and you get over exposure.

One test I use on older lenses to see if they are working is take the lens off the camera. Look at the back of the lens and through the glass, the aperture should be nearly closed with just a tiny hole. Move the aperture lever so that the blades go wide open. Let go of the aperture lever. The blades should snap closed, and I mean SNAP. No hesitation at all. If there is any delay at all then there is a problem. This test is not definitive but can often show a problem.
06-29-2014, 10:06 AM   #14
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Its time to do serious testing not stabbing at possibilities.


set up a test


use absolutely consistent lighting that is unvarying


use a tripod


use manual mode


photograph an object


remove all variables


Then take a series of images


examine the exifs and compare the exifs with the images.


Has this behaviour stopped.


If it has use an automatic setting do the same again


is this behaviour happening, if not change the mode until every mode has been tested one at a time


If you see the behaviour compare the exifs and see if the behaviour is consistent with the exifs exposure data


If the behaviour is happening and the lighting is consistent and the camera is on a tripod and the subject never moves then the problem will show in some way in the exifs. Either the camera does change the exposure, and that shows in varying exif data, or the camera thinks it exposes every image exactly the same and that too will be shown in the exifs


If the camera thinks its exposing exactly the same and that shows in the exifs, but the exposure varies, then theres a fault,


If you cant reproduce the problem with consistent lighting stationary subject and tripod, then the issue would appear to be some other factor such as technique or metering mode issues or transient effects that skew the metering or even hardware issues that affect the sensor.


If its happening with more than one lens it is almost certainly camera centred in some way.


You cant simply take different images in different conditions using different settings and try to work out where the problem is, you have to make dozens of test sets of images with everything the same and only one variable changing at once. Each test must be at least 3 images all exactly the same starting with everything totally under control in manual mode.


There are no shortcuts to this.
06-29-2014, 11:28 AM   #15
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Remove the lens and move the aperture lever with your thumb The body will hold it open to focus and meter, then let it go to the set aperture when you shoot. The spring operates it. If it is sticking it will show up if you do it repeatedly. I have one that sticks very intermittently and I can replicate it manually.
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