Why are these images different?


Link Posted 26/03/2012 - 09:12
Can anyone tell me what I've done wrong here? The light level of the pictures is completely different but the only thing I did was take about one step to the right between them. They were taken within 0.04 of a second of each other. They were taken in Green mode (i.e camera chooses settings) on the K5 with the 18-135mm lens, F11, ISO200,18mm, l/100 sec.

K5 + 18-135mm kit lens


Link Posted 26/03/2012 - 09:31
I think it's because you have moved the center of the image down as well as across, the camera is metering for the back of " fire "
Too Old To Die Young



Link Posted 26/03/2012 - 09:41
Thanks Barrie, I'll read up on metering and see if I can improve. I've been getting this type of effect quite a lot, which is why I thought if I used Green mode, the camera would get it right.
K5 + 18-135mm kit lens


Link Posted 26/03/2012 - 09:49
Now I do feel a fool, the camera was set on spot metering.
K5 + 18-135mm kit lens


Link Posted 26/03/2012 - 10:09
I wonder: You have your camera set on multi segment metering (pattern). The second photo has allowed for the darkness of the hearth. The first is better balanced overall. Photos are 4 seconds apart. If you had camera set on centre weighted you could better control the exposure. Looking at my own K5 I find I normally have it set at centre weighted. Perhaps this explains the different exposures???? I am assuming photos are not cropped. Cheers

PS Hi Frankie, Green mode defaults to Multi seg not spot mode. Cheers

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Last Edited by beachboy2 on 26/03/2012 - 10:15


Link Posted 26/03/2012 - 10:11
Try using centre weighted metering - you will need to use exposure compensation for very light or very dark subjects, but overall you should get very little over exposure.
Best regards, John


Link Posted 26/03/2012 - 10:33
Frankie wrote:
Now I do feel a fool, the camera was set on spot metering.

We all learn more from our creative experimentation


Link Posted 26/03/2012 - 12:13
No need to feel a fool, I think that most of us have made this mistake. The good thing with this forum is that you will always get constructive help with your problems.
Regards John/Jumbo


Link Posted 26/03/2012 - 14:13
BeachBoy2 was right when he said that in Green mode the camera defaults to Multi-Segment metering. So my spot metering was correctly overruled by the camera. Both pictures therefore had multi-segment metering, which Photo-Me confirms. Is it normal to have this much difference in exposure by changing the focus point slightly? It is more likely, since I was rushing, that I didn't give the camera time to meter correctly - is that a possibility?
K5 + 18-135mm kit lens


Link Posted 26/03/2012 - 14:39
Maybe I'm missing something, but both photo's have the same exposure values, 1/100 @ f11, so like 'Frankie' I would have expected the images to be similar as there doesn't appear to be an increase in light or dark parts in the scene.

Awaiting enlightenment.



Link Posted 26/03/2012 - 15:20
According to this link even multi segment metering is biased toward the centre. In these two images the actual centre is vastly different.

Maybe it's more biased than we think.

The review say's "The K-5 gives you the option to link the AF points to autoexposure in Multi-segment mode, via Custom Function 6, "Link AE to AF Point", but the default is to determine exposure without considering AF point location." Worth checking?
Too Old To Die Young



Link Posted 26/03/2012 - 15:41
Something doesn't seem quite right here. The two images clearly have been exposed differently and the light intensity would appear to be very similar in both, yet the EXIF data shows the same shutter speed, aperture, ISO, and EV comp for both images.

Irrespective of which metering mode was chosen, the EXIF data shows them to have identical exposure information, yet they are clearly different.

Is it possible that one of the images has had some kind of 'auto' correction applied?

Can you check the EXIF data in the source images and tell us if they are in fact identical?
Peter E Smith

My flickr Photostream


Link Posted 26/03/2012 - 16:20
Based on those, Exif readings should be different. If not it's the exif that's wrong.
... just another middle-aged guy with a hobby. I have an extreme macro learning site at extreme-macro.co.uk - Pentax-centric, your feedback and comments would be appreciated!


Link Posted 26/03/2012 - 21:01
Whilst on a model shoot on Saturday, I took two pictures less than a second apart on my K-5 without moving the camera at all and without adjusting any settings. The scene was identical, yet the results were very different! One is the correct colour, the other came out with a purplish tinge, as if the white balance had changed! The exposures were ever so slightly different too. The camera was set on AWB but the light did not change so this should not have been a factor. Exposure was set on manual, so no variables here.

This is not something I have experienced before or since, so I have no easy explanation!

Could I make a suggestion that your issue could be a lens aperture problem? If the aperture is not opening / closing quickly enough, could this cause the symptoms displayed in your image? It's not an explanation for what happened to me as I was using a SMC Takumar M42 in fully manual mode, but it may be worth investigating.


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Some cameras, some lenses, some bits 'n' bobs


Link Posted 26/03/2012 - 21:43
The EXIFs are identical except for a small difference in the no of bytes in the images; the half-press shutter time on the first image was 4.25sec and on the second image it was 1.9 sec. The AF Predicor and AF Defocus numbers are different, although the numbers mean nothing to me.
K5 + 18-135mm kit lens
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