Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-09-2016, 06:01 AM   #1
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 5,916
Weird effect in images on K-3... anyone seen this before?

I've noticed this a couple of times before, but this is a pretty extreme example... I took this photo with my K-3 a couple of days ago. It was sunny, and there was sunlight shining directly onto our cat. Photo taken with the DA*60-250 wide open at f/4. If you look at the whiskers, and the fur to the upper left of the image, there are areas that a multi-coloured - red, magenta, yellow, green, blue etc. If I look really carefully, I can make this out at 1:2 and even 1:3 reproduction. The crops below are at 1:1 and 2:1 to show the effect at its worst. The photo is a raw DNG file viewed in Lightroom 6, but the effect is visible in DCU5 also.

Has anyone come across this effect before? Is it a K-3 or Pentax thing, or a general issue with digital sensors - or something else?

EDIT: Hang on... is this moiré I'm seeing? I can remove it using Lightroom's Moiré slider, it seems!

Attached Images
   

Last edited by BigMackCam; 07-09-2016 at 06:11 AM.
07-09-2016, 07:09 AM   #2
Site Supporter
sundr's Avatar

Join Date: Jun 2012
Location: St. Paul, Minnesota
Photos: Gallery
Posts: 123
It may be moire but it may also be due to the structure of the cats fur causing different light waves to be reflected. It's been a long time since I studied biology but I don't think any black animal is absolutely black. It's common to see a shimmer of other colors. I wouldn't try to remove it. I don't see it as an artifact. Just my opinion.

Last edited by sundr; 07-09-2016 at 07:21 AM.
07-09-2016, 07:34 AM   #3
Senior Member




Join Date: Feb 2011
Location: Suceava, Romania
Photos: Albums
Posts: 132
You're overanalyzing because of that new 60-250 of yours (congrats btw)

Under direct sunlight, with the naked eye you'll see the same light effect on dark fur
07-09-2016, 07:42 AM   #4
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 5,916
Original Poster
QuoteOriginally posted by sundr Quote
It may be moire but it may also be due to the structure of the cats fur causing different light waves to be reflected. It's been a long time since I studied biology but I don't think any black animal is absolutely black. It's common to see a shimmer of other colors. I wouldn't try to remove it. I don't see it as an artifact. Just my opinion.
QuoteOriginally posted by Penumbra Quote
You're overanalyzing because of that new 60-250 of yours (congrats btw)

Under direct sunlight, with the naked eye you'll see the same light effect on dark fur
Thanks, both Well, that's yet another thing I've learned from these forums (though it sounds like perhaps I should have been listening closer in science classes ) - much appreciated!

07-09-2016, 09:48 AM   #5
Site Supporter




Join Date: Mar 2008
Location: Prince George, BC
Photos: Gallery
Posts: 2,268
It is refracted iridescence, same mechanism that gives many bird feathers their colour. Nothing wrong with your camera.
07-09-2016, 10:19 AM   #6
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 5,916
Original Poster
QuoteOriginally posted by jbinpg Quote
It is refracted iridescence, same mechanism that gives many bird feathers their colour. Nothing wrong with your camera.
Thank you Yes, in fact it does look very similar to the colour I see in starlings...
07-09-2016, 10:49 AM   #7
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,029
Take a strand of your hair and examine it in bright light - sunlight is ideal. Hair is translucent and the pigment and cell structure diffracts light in many ways.
07-10-2016, 05:22 AM   #8
Pentaxian
Pål Jensen's Avatar

Join Date: Dec 2007
Location: Norway
Photos: Albums
Posts: 3,073
QuoteOriginally posted by jbinpg Quote
It is refracted iridescence, same mechanism that gives many bird feathers their colour. Nothing wrong with your camera.
Maybe there's something wrong with the cat!

07-10-2016, 05:24 AM   #9
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 5,916
Original Poster
QuoteOriginally posted by Pål Jensen Quote
Maybe there's something wrong with the cat!
I'll tell him you said this... He won't be amused!
07-10-2016, 05:32 AM   #10
amateur dirt farmer...
pepperberry farm's Avatar

Join Date: Dec 2014
Location: probably out in a field somewhere...
Photos: Gallery | Albums
Posts: 6,394
we have black dogs and I will see a similar effect in them (both naked eye and photos) when in strong light (sunlight or artificial) - I would not consider this an issue with the lens or camera....
07-10-2016, 06:19 AM   #11
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 5,916
Original Poster
Thanks, Dave... so long as I know it happens and isn't a problem, I'm cool with it. It's not that noticeable, and as I mentioned, the moiré slider in LR6 removes it effectively
07-10-2016, 06:23 AM   #12
amateur dirt farmer...
pepperberry farm's Avatar

Join Date: Dec 2014
Location: probably out in a field somewhere...
Photos: Gallery | Albums
Posts: 6,394
QuoteOriginally posted by BigMackCam Quote
Thanks, Dave... so long as I know it happens and isn't a problem, I'm cool with it. It's not that noticeable, and as I mentioned, the moiré slider in LR6 removes it effectively
of course, you could always ask your model (cat) to move out of the sun.....


(:
07-10-2016, 06:32 AM - 1 Like   #13
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 5,916
Original Poster
QuoteOriginally posted by pepperberry farm Quote
of course, you could always ask your model (cat) to move out of the sun.....
I suspect that would be met with the same disregard as any other requests made of him... but I'll try. He's going through a mousing phase right now and seems to think "Put it down!" and "Let it go!" means "Bite down hard" or "Bring that inside the house!"
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, couple, dslr, effect, effect in images, k-3, photo, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Anyone identify this problem? Saving images on K-50 tranq78 Pentax K-30 & K-50 3 06-03-2016 06:39 AM
Has anyone seen this haze on glass before? thehabit Pentax SLR Lens Discussion 9 06-27-2015 05:49 AM
Lifting Shadows - effect on prints- anyone seen this? Clarkey Digital Processing, Software, and Printing 7 06-17-2012 06:55 PM
Anyone seen this ring flash before? Thoughts?? JayR Flashes, Lighting, and Studio 25 05-18-2012 06:50 AM
One photo in JPEG - HDR effect - anyone try it before? Flickeroo Digital Processing, Software, and Printing 8 10-29-2010 11:16 AM



All times are GMT -7. The time now is 07:29 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top