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01-20-2020, 09:09 PM   #1
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Same ISO, f-stop, shutter speed but different exposures?

While shooting in continuous high, I've recently noticed some pictures showing up overexposed despite having the same exposure settings. I've also heard my shutter make some strange noises, almost like it's sliding rather than "clacking"

Both of these pictures are ISO 400, f/14, 1/250 but clearly have different exposures. Am I not taking something into consideration or is this an early sign of shutter failure?

edit: The first picture is the proper exposure.

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Last edited by PushTheRedButton; 01-20-2020 at 09:41 PM.
01-20-2020, 09:43 PM - 1 Like   #2
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If anything I would suspect this being aperture a bit slow stopping down.

Stopping down the lens this much in continous high put a lot demand on the aperture mechanism. Maybe more than it was designed for.
Do you see the same problem shooting with aperture wide open?
01-20-2020, 09:51 PM   #3
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That's an interesting thought. I've never paid attention to that. I'll give that a look by just firing off lots of shots and comparing the two apertures, but I've been shooting sunsets almost every day for the last 7 months, always on continuous high, usually between f/8 and f/14 and this issue only started happening recently. Sometimes I shoot pretty wide open but with all the birds I like to have as much as a DOF as possible.
01-20-2020, 09:52 PM - 1 Like   #4
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Are they in-camera jpegs, or were they converted from Raw?

If the former, could the K5's jpeg engine just be making a different choice of processing options in the two frames? Given the high dynamic range of this image, it seems possible.

01-20-2020, 10:04 PM   #5
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Have you always used this lens for sunsets?
As it is a macro lens with 9 aperture blades it may not be an aperture mechanism optimized for speed.
01-20-2020, 10:16 PM - 1 Like   #6
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QuoteOriginally posted by Paul the Sunman Quote
Are they in-camera jpegs, or were they converted from Raw?
If the former, could the K5's jpeg engine just be making a different choice of processing options in the two frames? Given the high dynamic range of this image, it seems possible.
kinda curious of this as well.......also have had cases were awb did some weird stuff.....in particular remember shooting some silver like tanks and had a few odd balls where they turned out very magenta versus silver.....but there is no notable color cast just the over exposure
01-20-2020, 10:17 PM   #7
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QuoteOriginally posted by Paul the Sunman Quote
Are they in-camera jpegs, or were they converted from Raw?

If the former, could the K5's jpeg engine just be making a different choice of processing options in the two frames? Given the high dynamic range of this image, it seems possible.
They were imported to lightroom from raw, then exported to photoshop and saved as jpegs, but I first noticed the issue while reviewing photos immediately after taking them.

QuoteOriginally posted by Fogel70 Quote
Have you always used this lens for sunsets?
As it is a macro lens with 9 aperture blades it may not be an aperture mechanism optimized for speed.
Yes, I've always used this lens. With the exception of just having a narrow FOV it's always been very good to me until recently (check out the shot I just posted in the K5 forum). The over-exposure issue started maybe 3 weeks ago and the shutter sound started maybe 10 days ago. If you shoot continuous high regularly the shutter sound is clearly noticeable but it's random.

Even if it's overcast tomorrow I'll carry it with me just to test out the aperture settings and see if that makes a difference.
01-21-2020, 01:11 AM   #8
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QuoteOriginally posted by PushTheRedButton Quote
I've been shooting sunsets almost every day for the last 7 months, always on continuous high, usually between f/8 and f/14
That will put a lot of strain on the shutter, mirror and aperture mechanism. Electronics tend to be quite robust when used as designed but there are some mechanical systems that will inevitably wear out in the fullness of time. The failure could involve just one component or several. Sometimes Memory cards which aren't designed to deliver high sustained data rates can cause problems.

01-21-2020, 04:08 AM   #9
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How many shutter activations does the camera have? It might just be worned after years of use in continuous shooting...
01-21-2020, 04:17 AM   #10
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QuoteOriginally posted by CarlJF Quote
How many shutter activations does the camera have? It might just be worned after years of use in continuous shooting...
If the camera shutter is gone, the results look complelty different from this.


I think the best guess so far is the aperture indeed.

You can check this by shooting a scenario with bokeh and see if the bokeh changes on those shots.
01-21-2020, 04:40 AM - 1 Like   #11
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QuoteOriginally posted by CarlJF Quote
How many shutter activations does the camera have? It might just be worned after years of use in continuous shooting...
I have a K5IIS that I use for timelapse has over 300,000 shutter firings*, it works fine. though I will mention the shutter sound is louder and higher pitched than my less abused K5IIs cameras.

* I recently did a check of my K10D and it is well over 100,000 Shutter firings, i'm pretty sure that shutter is only rated for 50,000 firings. But then again I had a Canon 1DsMKII N shutter fail on me only after around 20,000 firings and that shutter is rated for 5X that. One of my Leaf shuttered Leica S lenses malfunctioned on me once ( To Leica's credit, they did the repair free of charge as the lens developed the fault a week after it was last serviced). So when it comes to camera shutters and other mechanical components used in cameras your mileage will vary.

Last edited by Digitalis; 01-21-2020 at 04:49 AM.
01-21-2020, 06:05 AM   #12
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Hello,

A few years ago, I had a similar situation but the frames were getting darker instead of overexposed. I sent the lens (F50-f1.7) to Eric for servicing. It was not able to cope with the frame rate of my K5-II. After servicing, it's been working flawlessly for about 3 years now. Not sure if that may be relevant to your case.

Thanks,
01-21-2020, 12:05 PM   #13
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You can test the lens by opening and closing the diaphragm release manually

If it goes fast and smoothly then the lens is OK
If the diaphragm blades are slow and sticky, then the lens is wrong
01-21-2020, 08:49 PM   #14
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QuoteOriginally posted by Digitalis Quote
That will put a lot of strain on the shutter, mirror and aperture mechanism. Electronics tend to be quite robust when used as designed but there are some mechanical systems that will inevitably wear out in the fullness of time. The failure could involve just one component or several. Sometimes Memory cards which aren't designed to deliver high sustained data rates can cause problems.
QuoteOriginally posted by CarlJF Quote
How many shutter activations does the camera have? It might just be worned after years of use in continuous shooting...
28,865 as of tonight.

Even though I keep the camera in continuous high, I'm not always blasting away At most I fire off 6-7 shots at a time when birds fly through the shot but otherwise it's always just a single shot.

QuoteOriginally posted by WorksAsIntended Quote
If the camera shutter is gone, the results look complelty different from this.


I think the best guess so far is the aperture indeed.

You can check this by shooting a scenario with bokeh and see if the bokeh changes on those shots.
The problem is it's very intermittent. The majority of shots are just fine but it randomly over-exposes a shot here and there, but I'll do what I can to keep an eye on things like that.

QuoteOriginally posted by ismaelg Quote
Hello,

A few years ago, I had a similar situation but the frames were getting darker instead of overexposed. I sent the lens (F50-f1.7) to Eric for servicing. It was not able to cope with the frame rate of my K5-II. After servicing, it's been working flawlessly for about 3 years now. Not sure if that may be relevant to your case.

Thanks,
Thanks for the comment, I just might have to do that but at this point I don't want to put any more money into this camera.

QuoteOriginally posted by Crooski Quote
You can test the lens by opening and closing the diaphragm release manually

If it goes fast and smoothly then the lens is OK
If the diaphragm blades are slow and sticky, then the lens is wrong
I understand what you're talking about. Using the little lever on the inside of the lens everything operates smoothly and quietly, but maybe this is an early sign of the diaphragm problems/failure?
01-22-2020, 05:57 AM   #15
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QuoteOriginally posted by PushTheRedButton Quote
While shooting in continuous high, I've recently noticed some pictures showing up overexposed despite having the same exposure settings. I've also heard my shutter make some strange noises, almost like it's sliding rather than "clacking"

Both of these pictures are ISO 400, f/14, 1/250 but clearly have different exposures. Am I not taking something into consideration or is this an early sign of shutter failure?

edit: The first picture is the proper exposure.
Is it something to do with auto white balance.

Shutter failure would leave a black band on the bottom of the shot.
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