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05-26-2008, 08:20 PM   #1
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K20D and the Tamron 70-300 - Has the Purple Monster been slain?

From Pentax Imaging - Pentax Press Release - "Also, there is a more direct light path to the pixels." - In another article or press release somewhere (sorry, I can't find the reference at the moment), I remember seeing an elaboration on this saying that it should improve IQ with legacy lenses.

I just used my new K20D for the first time with my Tamron 70-300 at the Buffalo Zoo this past weekend. In reviewing my shots so far, I cannot see PF in ANY of them, even ones in conditions I'm sure would have caused severe PF on my K10D.

(No examples yet, expect an edit in a day or two with one or two, I just got in from 4 hours on the road.)

Could it be that the K20D's improved sensor site to pixel area ratio (and reduced need for an antialiasing filter) has slain the Purple Monster?

05-26-2008, 08:41 PM   #2
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I've had very good results with this lens on the k20d also. however, purple fringing has shown up in a few shots. it is very minimal and was easily removed with cs3
05-27-2008, 05:10 AM   #3
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I have this lense on my K100D super...
No problem as of yet!
But not used it much either...
Will watch out for the purple fringing
05-27-2008, 07:14 AM   #4
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Try this test in direct sunlight (find a metal fence)...this was done w/ the K10D:

Notice CA (the green stuff) and PF (the purple stuff). There's slight VPN on the blue background as well.

05-27-2008, 08:04 AM   #5
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I spoke too soon - one of my shots does have some PF.

Just as a note: I used this same lens for nearly a year on my K10D, and had PF in quite a few situations. There were numerous cases last weekend where I shot in conditions that would have PFed severely on my K10D but didn't on my K20D (such as water droplets in bright sunlight).

It's not a magic bullet or 100% fix, but the K20D definately does seem to be more forgiving with the Tamron 70-300.
05-27-2008, 01:31 PM   #6
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I wrote up a blog post on fixing purple fringe with free tool that I use with XnView and PFree photoshop plugin, quite easy to use.



Thanks,
Hin
05-27-2008, 01:57 PM   #7
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I haven't noticed as much CA with this lens on my K20 (vs my K100) but I have noticed it seems softer up to about F11 at 300mm in high contrast situations. White against nearly anything with lots of sun seems to be very soft.
05-27-2008, 02:23 PM   #8
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QuoteOriginally posted by hinman Quote
I wrote up a blog post on fixing purple fringe with free tool that I use with XnView and PFree photoshop plugin, quite easy to use.

Ah, another XNView user among us.

If you haven't already, try the Virtual Photography plugin for quick touch-ups and effects. If used appropriately, you can get quite spectacular results!

05-27-2008, 03:15 PM   #9
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That's pretty cool, Hin. Too bad that won't get rid of the green CA (top of fence behind bird) in that fence test :-P
05-27-2008, 05:11 PM   #10
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QuoteOriginally posted by hinman Quote
I wrote up a blog post on fixing purple fringe with free tool that I use with XnView and PFree photoshop plugin, quite easy to use.



Thanks,
Hin
Is there a CA corrector for MAC OS? I am using PS3 but am wondering if there is another possibility.

Thanks
Ben
05-27-2008, 05:34 PM   #11
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QuoteOriginally posted by benjikan Quote
Is there a CA corrector for MAC OS? I am using PS3 but am wondering if there is another possibility.

Thanks
Ben
Ben,

Thanks for the question. I don't have a Mac and I go back and double check on XnView, it does support mac but the photoshop plugin that I used is PFree and it only works for windows environment.

I did mention the Links of Pfree and XnView in my page:

Purple Fringe with Tamron 70-300 Di LD Macro - Hin's Tech Corner

Listed below for quicker references:
I am sure your Photoshop CS3 will do a better job than the free plugin. I only go for the free tool when I don't have a budget for tools and I opt for the cheaper alternative without any fee :-)

Thanks,
Hin
05-28-2008, 12:41 AM   #12
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XNView does NOT work on Mac OS anymore. The developer pulled its support because of various problems.

They are working on a new and improved code base that will make XNView run stable on all OSs.
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