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05-08-2015, 12:06 AM   #16
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Thanks a lot, great links!

05-08-2015, 12:42 AM   #17
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This is the photo from which the first crop comes from, dng opened in PS and changed size to fit this forum. No other changes made.
I used Av mode and as you can see parts of the sky are overexposed and to the extent that there aren't almost any info in some areas so those areas aren't effected by PP (exposure for example). On the other hand some parts are almost underexposed instead.

I don't know if I messed something up with the settings, the camera should do better than this in my mind. Most likely I'm doing something wrong.
Perhaps the K-3 is more correct than the K-5 which in general seems to underexpose and I cling to how the K-5 performs. I'll try with exposure compensation but it feels like a workaround rather than a solution. I'm a fan of the Av mode but as it looks I need to abandon it since overexposure seems to make the purple issue worse.

Exif for this photo from the dng-file.
Subfile Type : Reduced-resolution image
Image Width : 160
Image Height : 120
Bits Per Sample : 8 8 8
Compression : Uncompressed
Photometric Interpretation : RGB
Make : RICOH IMAGING COMPANY, LTD.
Camera Model Name : PENTAX K-3
Strip Offsets : 153696
Orientation : Horizontal (normal)
Samples Per Pixel : 3
Rows Per Strip : 120
Strip Byte Counts : 57600
X Resolution : 300
Y Resolution : 300
Planar Configuration : Chunky
Resolution Unit : inches
Software : PENTAX K-3 Ver. 1.11
Modify Date : 2015:05:03 11:25:19
Artist : THOMAS MATTSSON
Subfile Type : Full-resolution Image
Image Width : 6080
Image Height : 4032
Bits Per Sample : 14
Compression : JPEG
Photometric Interpretation : Color Filter Array
Strip Offsets : 211296
Samples Per Pixel : 1
Rows Per Strip : 4032
Strip Byte Counts : 33305120
X Resolution : 300
Y Resolution : 300
Planar Configuration : Chunky
Resolution Unit : inches
CFA Repeat Pattern Dim : 2 2
CFA Pattern 2 : 0 1 1 2
CFA Layout : Rectangular
Black Level Repeat Dim : 2 2
Black Level : 0 1 1 1
White Level : 16316
Default Scale : 1 1
Default Crop Origin : 6 12
Default Crop Size : 6016 4000
Bayer Green Split : 0
Anti Alias Strength : 1
Active Area : 4 10 4028 6038
Subfile Type : Reduced-resolution image
Image Width : 6016
Image Height : 4000
Bits Per Sample : 8 8 8
Compression : JPEG
Photometric Interpretation : YCbCr
Preview Image Start : 33516416
Samples Per Pixel : 3
Rows Per Strip : 4000
Preview Image Length : 3247467
X Resolution : 300
Y Resolution : 300
Planar Configuration : Chunky
Resolution Unit : inches
White Point : 0.313 0.329
Primary Chromaticities : 0.64 0.33 0.3 0.6 0.15 0.06
Y Cb Cr Coefficients : 0.299 0.587 0.114
Y Cb Cr Sub Sampling : YCbCr4:2:2 (2 1)
Y Cb Cr Positioning : Co-sited
Preview Color Space : 2
Copyright : THOMAS MATTSSON
Exposure Time : 1/800
F Number : 2.8
Exposure Program : Aperture-priority AE
ISO : 100
Sensitivity Type : Standard Output Sensitivity
Standard Output Sensitivity : 100
Date/Time Original : 2015:05:03 11:25:19
Create Date : 2015:05:03 11:25:19
Exposure Compensation : 0
Metering Mode : Multi-segment
Flash : Off, Did not fire
Focal Length : 34.4 mm
Sensing Method : One-chip color area
Custom Rendered : Normal
Exposure Mode : Auto
White Balance : Auto
Focal Length In 35mm Format : 51 mm
Scene Capture Type : Standard
Contrast : High
Saturation : Normal
Sharpness : Hard
Subject Distance Range : Distant
GPS Version ID : 2.3.0.0
DNG Version : 1.2.0.0
DNG Backward Version : 1.2.0.0
Unique Camera Model : PENTAX K-3
Color Matrix 1 : 0.9413604736 -0.4662322998 -0.07719421387 -0.3495941162 0.9834136963 0.4286651611 -0.02014160156 0.04209899902 0.7699890137
Color Matrix 2 : 0.8306732178 -0.2510223389 -0.1112518311 -0.3995361328 1.230117798 0.1880645752 -0.1025238037 0.1797637939 0.6834411621
Analog Balance : 1 1 1
As Shot Neutral : 0.4563279857 1 0.6632124352
Baseline Exposure : -0.506149292
Baseline Noise : 1
Baseline Sharpness : 1
Linear Response Limit : 1
Calibration Illuminant 1 : Standard Light A
Calibration Illuminant 2 : D65
Preview Color Space : 2
Attached Images
View Picture EXIF
PENTAX K-3  Photo 
05-08-2015, 01:28 AM   #18
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QuoteOriginally posted by Samoht Quote
This is the photo from which the first crop comes from,
To my eyes, that is very modest PF. I've seen a lot worse!

You could just tick the box in Lightroom and it would clean that up without further intervention from you.

And since it's an ISO 100 shot, you could easily boost the shadows and recover the highlights to your hearts content in PP.
05-08-2015, 02:10 AM   #19
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Isn't there a setting to correct for CA.
Would you have enabled that at some point on the K5 and forgotten to do it on the K3?

05-08-2015, 02:32 AM   #20
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Maybe, please read my post above again.

The problem you are experiencing is optical and only optical. Sensor and overexposure can affect how you experience the problem but it won't really matter.

What you see is an artefact of excessive edge contrast between different planes of focus. EVERY lens will exhibit some PF in this situation.

Imagine a sky 1000x (10 stops) brighter than the forground, clipped to 100% white, foreground at 18% gray. And now imagine just 1% of the light spills around the edge for optical reasons (CA and others -- aberrations like the unavoidable diffraction tend to be color dependent anyway). Than this 1% is 60x brighter than your foreground completely ruining your foreground edge. What you see still isn't all that bad for a high contrast situation.

If you underexpose, profile CA correction can do a better job but otherwise, it won't matter if you underexpose the shot or later in postprocessing.
05-08-2015, 03:49 AM - 1 Like   #21
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I note both images were (1) wide open at F2.8 so limited DOF and (2) focused on an open mass of trees so what the autofocus locked onto is possibly a lottery. So focus accuracy could well be part of the issue here.

Also, could the AF calibration of the 17-50 be a bit out on the K-3 so you are starting to fringing on mildly OOF elements of the image? Lens might have been calibrated ok on the K-5 but not so on the K-3.

EDIT: ok, just saw the full image posted. The tree with fringing I would suspect is well forward on the plane of focus (the building??) so this is oof fringing. With my M200/4 I actually use the fringing to fine tune focus. The M 200/4 clearly purple fringes around the subject edges when focus is behind the subject and fringes green when focused in front. Very obvious when using magnified live view so I focus to the transition from purple to green fringing in order to identify optimum focus. Definitely gets the best out of the M200/4 as it is not the best corrected lens Pentax ever made.

Last edited by southlander; 05-08-2015 at 04:02 AM.
05-08-2015, 04:44 AM   #22
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QuoteOriginally posted by southlander Quote
I actually use the fringing to fine tune focus
Interesting - using the fringing like focus peaking!
Turns a negative into a positive.
05-08-2015, 05:05 AM   #23
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Yes, I'm ok with and understand the CA/fringing "issue".

Was a bit unclear and perhaps off topic in my previous post, sorry about that. I've been noticing that K-3 tends to overexpose sometimes at least comparing to the K-5 which tends to underexpose so my previous post was about this "issue".

I'm used to the K-5 and its slightly underexposing so regarding the overexposing with K-3 I probably just need to adjust myself to the K-3 and get used to it. Both metering and focus points are different and to be honest I haven't really looked into the metering settings, back to school in other words.

05-09-2015, 04:41 AM   #24
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I've come from K-x to a K-3. One of the first things I noticed was how well the K-3 protects highlights and I have very little in the way of complaints about my K-3 overexposing. I think I have the highlight protection feature turned on and I also shoot RAW and rarely have major overexposure issues other than the obvious challenge conditions like sunsets with the sun still above the horizon.

---------- Post added 9th May 2015 at 09:23 PM ----------

QuoteOriginally posted by rawr Quote
Interesting - using the fringing like focus peaking!
Turns a negative into a positive.
Sounds a bit odd doesn't it but I had some time with the M200/4 during a Single in challenge and came to the conclusion that the best way to get the lens to perform was (1) spot on focus otherwise the CA around the subject edges quickly made the lens look less sharp than it was (not real high to start with, the K-3 out-resolves it) and (2) use a polariser filter wherever possible to get some contrast back into the thing. With those two actions, the M200/4 actually shows some nice character.

I find I can use the same technique with the M400/5.6.
05-12-2015, 12:52 PM   #25
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My overall impression regarding the move from lower mega-pixel sensors with AA to the K-3 without AA is that lenses that aren't considered extremely sharp but are relatively free from LoCA, CA and PF perform very well and take to some added sharpening and micro-contrast enhancement quite well. Lenses that are quite sharp overall (such as the Tamron 17-50) but have aberration issues tend to falter and may not correct well - even with quality Raw conversion.
05-18-2015, 09:20 AM   #26
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Ehrm, I read the K-3 review here at PF and followed the recommended settings section.
I've come to the conclusion that every once and a while I tend to unknowingly press the RAW Fx button hence switching to Exposure bracketing, so the overexposure issue...

Need I say that the RAW Fx button is not set to Exposure bracketing any longer.
05-23-2015, 03:58 AM   #27
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I've noticed a little PF with my Tamron 17-50 with the K-3 whereas I rarely saw any with the K-x. I've put it down to the reason Adam suggested. Pure speculation on my part but I also wonder if the lack of an AA filter maybe plays a part at the margin as the K-3 will not be smearing a little PF over multiple pixels so it may be that it also is able to register the presence of a little purple a little more accurately at a pixel by pixel level.

Having said that the PF is quite minor other than torture situations and a very light touch of fringing removal in PP quickly removes it.
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