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11-16-2012, 10:31 AM   #1
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K5IIs and PF ?

Looking at the K5II vs K5IIs Review, it is noticeable that the K5IIs samples seem to lack Purple Fringing (PF) when the K5II clearly display the phenomenon. Can anyone confirm and even better perhaps demonstrate if this is indeed the case ?

11-16-2012, 10:41 AM   #2
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I also noticed that and will make the test as soon as I get mi K5IIs - unfortunately here in france quantities seem very limited. I'll test with lenses prone to purple fringing wide open such as FA85 f1.4 (the lens adam used to test) and DA*200
11-16-2012, 11:04 AM   #3
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Lack of fringing with the IIs was one of the surprising findings. I guess we'll have to conclude that the AA filter is responsible for at least some color fringing, it isn't just the lens and the microlenses on the sensor that are the culprits.
11-16-2012, 12:26 PM   #4
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It's definitely still there, but I only notice it at 100%.

Highlights - CIF Prelims 2012 - Digital Studio - RaceTime Photos

I usually shoot this lens at f/3.2 to f/4, partly for this reason, but I slipped down to f/2.8 for a few shots. The good news is I still get pretty good detail/sharpness/resolution, as long as I hit the focus.


Normally, this lens (FA135) needs to be stopped down to f/4 to eliminate PF, but notice its complete absence on this follow-up shot at f/3.5:

http://www.racetimephotos.com/XC/CIFPrelims2012/CIFPrelims2012Highlights/257...bMLmD&lb=1&s=O


This is at a different location with nearly identical lighting (though my camera position differs), but even at f/3.2 the PF is minimal on the K-5 IIs:

http://www.racetimephotos.com/XC/CIFPrelims2012/CIFPrelims2012Highlights/257...mJCV4&lb=1&s=O


Last edited by DSims; 11-16-2012 at 01:08 PM.
11-16-2012, 12:34 PM   #5
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QuoteOriginally posted by DSims Quote
It's definitely still there, but I only notice it at 100%.

Highlights - CIF Prelims 2012 - Digital Studio - RaceTime Photos

I usually shoot this lens at f/3.2 to f/4, partly for this reason, but I slipped down to f/2.8 for a few shots. The good news is I still get pretty good detail/sharpness/resolution, as long as I hit the focus.
Is it possible for you to give us an example the difference of your own with your lens?
11-16-2012, 01:10 PM   #6
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QuoteOriginally posted by regor Quote
Looking at the K5II vs K5IIs Review, it is noticeable that the K5IIs samples seem to lack Purple Fringing (PF) when the K5II clearly display the phenomenon. Can anyone confirm and even better perhaps demonstrate if this is indeed the case ?
I've been working with RAW studio samples from each system and found both units to be identical. However, there is something about the IIs which leads me to believe that the lack of AA filter leads to a purple or blue color cast in images. Which seems consistent according to my observations.
11-16-2012, 01:10 PM   #7
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QuoteOriginally posted by DSims Quote
It's definitely still there, but I only notice it at 100%.

Highlights - CIF Prelims 2012 - Digital Studio - RaceTime Photos

I usually shoot this lens at f/3.2 to f/4, partly for this reason, but I slipped down to f/2.8 for a few shots. The good news is I still get pretty good detail/sharpness/resolution, as long as I hit the focus.


Normally, this lens (FA135) needs to be stopped down to f/4 to eliminate PF, but notice its complete absence on this follow-up shot at f/3.5:

Highlights - CIF Prelims 2012 - Digital Studio - RaceTime Photos


This is at a different location with nearly identical lighting (though my camera position differs), but even at f/3.2 the PF is minimal on the K-5 IIs:

Highlights - CIF Prelims 2012 - Digital Studio - RaceTime Photos
Three different images?
11-16-2012, 01:52 PM   #8
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QuoteOriginally posted by JohnBee Quote
Three different images?
Yes, at three different f-stops, showing that I'm effectively able to go 1/2 to 2/3 stops wider with similar PF performance compared to earlier cameras.


This is hardly a controlled test, but real-world and relevant when taking action shots that may not get PP'ing treatment. I also think I'm getting better focusing with the IIs.

I've really had minimal interest in studying PF in the past, so perhaps someone can correct me if I'm wrong here, but it appears that slightly OOF areas have increasingly more PF on the K-5, but increasingly less PF on the K-5 IIs (compared to the in-focus areas in the same image). Has anyone else seen this, or do I need to look at more examples?

11-16-2012, 02:16 PM   #9
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QuoteOriginally posted by DSims Quote
I've really had minimal interest in studying PF in the past, so perhaps someone can correct me if I'm wrong here, but it appears that slightly OOF areas have increasingly more PF on the K-5, but increasingly less PF on the K-5 IIs (compared to the in-focus areas in the same image). Has anyone else seen this, or do I need to look at more examples?
I'm thinking it would be next to impossible to draw any type of conclusion with this particular approach myself. Though taking identical RAW images with both systems, they would likely be a step in the right direction. The other thing that I'd mention is where a focusing chart would likely help also since focusing could have an impact on the results as well.

Hope this helps.
11-16-2012, 02:16 PM   #10
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OOF areas should definitely have more CA, but I dunno bout PF.
11-16-2012, 03:39 PM   #11
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PF is definitely sensitive to even slight amounts of focus changes. Any conclusions should only be made on the basis of very controlled experiments.

My personal speculation is that the partial colour blindness of the K-5 IIs's sensor alleviates PF created by the lens, as opposed to an Bayer-AA-filter creating the PF; however that's pure speculation.
11-16-2012, 05:16 PM   #12
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QuoteOriginally posted by JohnBee Quote
I'm thinking it would be next to impossible to draw any type of conclusion with this particular approach myself. Though taking identical RAW images with both systems, they would likely be a step in the right direction. The other thing that I'd mention is where a focusing chart would likely help also since focusing could have an impact on the results as well.
Well, if others are noticing similar results, it's likely that it is reducing the occurrence of PF. Other unexpected and unannounced (by Pentax) benefits of the IIs have already been observed, such as the extra stop in SR performance. I've already speculated that Pentax may not have even noticed that one - or if they did, they didn't want to advertise it.

However, I'm content to leave the formal testing to others for now.
11-16-2012, 06:32 PM   #13
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I might see if I can take some high contrast images to check this out. I haven't noticed much purple fringing on my DA55-300 in the past, though.
11-16-2012, 08:24 PM   #14
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Really odd to see this thread.

Just yesterday I received a new K-01 (!!). Charged the battery, set it up, and started to snap samples.

Put my 77 Limited on it - a notorious PF machine in the right light/contrast. The samples from the K-01 were horribly plagued by PF, the worst I had ever seen it.

Hmmm.

So, proceeded to update the firmware. Smooth. Good.

Since the 77 was still on the camera I proceeded to shoot virtually the same shot. Almost zero PF. Could not even force it.

I think the firmware may have installed something in lens correction that removed the PF - or the v1.0 firmware had no correction for PF for the 77.

How interesting is that?
11-17-2012, 09:16 AM   #15
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Interesting about the FA77 on K-01. Can we see these shots 100% crop ?
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