Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-22-2013, 11:02 AM   #1
New Member




Join Date: Dec 2013
Location: Dortmund
Posts: 6
K-5 noise even with ISO 200 (was: K-5 IIs noise)

Hi,

I am new to DSLR photography, despite I am using a Canon Powershot G9 and G10 for family photography now for a long time. But my roots (when I had lots more time...) are Pentax K compatible analog cameras with manual and Auto Focus (2 manual focus No Names, 2 auto focus No Names) with some lenses from 28 mm to 500 mm fix lens and some zooms in between.

I am very happy with my K-5 which I bought as used camera some weeks ago. But when it comes to low light I see noise even with ISO 200 and a tripod.

On one day there was a party at a local company, which is selling swimming pools, where I made some outside photos of the building which was lighted in red and blue hands free. When coming home and checking the photos I was sad about some noisy pixels when there were soft areas between red and blue light. They were taken with ISO-640, which I do not find very problematic.

The day after I took my tripod with me. But even then I had problems with ISO-200. Is this normal with the K-5 or is specific to my individual item?

Regards,

Lutz

Attached Images
View Picture EXIF
PENTAX K-5  Photo 
View Picture EXIF
PENTAX K-5  Photo 
12-22-2013, 11:14 AM   #2
Pentaxian
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 10,325
Hey, welcome.
I think the issue there is colour saturation and noise reduction. Actual noise looks different, whether its luminance or colour noise.
Another thing to consider is that ISO 200 is not 100% noise-free, and if you post process the photograph a lot, you can bring that noise out. For example, if you brighten the photograph digitally, there will be much more noise.

So, to fix your issue, I suggest you shoot raw and play with the NR and color saturation+hue sliders, as well as White balance. Also, when you export as jpeg, if you resize the photo to make it smaller, a lot of the noise (actual noise) will disappear. Most people don't mind noise up to around ISO 3600. Maybe even higher.
If colour is oversaturated, then the detail there is drowned. If the NR is too high, it also removed fine detail and introduces artifacts. High contrast and oversaturation will lead to quick shifts from full to low saturation, which will appear as noise

Oh, and one more thing, LED lights are really terrible for photography and they can make odd casts like that. I think there were a couple threads with problems with odd colours due to LED lights, even blog posts. They oversaturate one colour channel, but they don't produce other colours at all, so you can't fix them much.
None of these is a Pentax-specific issue btw. Except if you shoot jpeg and the jpeg mode is bright or vibrant and you have noise reduction turned up high, but those are settings you can change.

Last edited by Na Horuk; 12-22-2013 at 11:24 AM.
12-22-2013, 12:00 PM   #3
Site Supporter
kiwi_jono's Avatar

Join Date: Dec 2009
Location: Christchurch, New Zealand
Photos: Gallery | Albums
Posts: 1,035
Welcome - the K-5 is a great camera.
I agree with Na Horuk - it looks like a colour channel maxed out.
It would be interesting to see colour exposure charts (can be shown when viewing photos on K-5) - I suspect you would see one channel biased to the right of the chart.
BTW (in case you have not done this) to see exposure chart (in play mode):
* Press Info until you see normal exposure chart
* Press up or down arrow button to see colour charts

Also it is possible to see a small amount of noise at ISO200 on a K-5 if an image (or part of) is significantly underexposed. I prefer to keep ISO to 800 or below but sometimes use up to 3200 when I need to.
12-22-2013, 12:13 PM   #4
New Member




Join Date: Dec 2013
Location: Dortmund
Posts: 6
Original Poster
Hi Na Horuk and Jonathan,

happily I have taken RAW+ and a 3 photo row of under-, right- and overexposure. The uploaded files already were the best. I will test with the RAW files as recommended by both of you and will check the colour chart in the cam tomorrow, as I donīt have it with me at the moment. Maybe the spotlights the event team used were LED lights.

Thanks,

Lutz

12-27-2013, 08:06 AM   #5
New Member




Join Date: Dec 2013
Location: Dortmund
Posts: 6
Original Poster
Hi Na Horuk and Jonathan,

I now had time to shoot a screenshot of the colour chart. Find these included.

Regards,

Lutz
Attached Images
View Picture EXIF
7 Mozart  Photo 
View Picture EXIF
7 Mozart  Photo 
12-27-2013, 08:10 AM   #6
Pentaxian
VisualDarkness's Avatar

Join Date: Nov 2011
Location: Uppsala, Sweden
Photos: Gallery
Posts: 4,439
Huge over-exposure for blue, no wonder it looks over-saturated like that. Is it LED-lighting?
12-28-2013, 12:46 AM   #7
Site Supporter
Ex Finn.'s Avatar

Join Date: Nov 2007
Location: Southern Maryland.
Photos: Gallery | Albums
Posts: 6,060
QuoteOriginally posted by VisualDarkness Quote
Huge over-exposure for blue, no wonder it looks over-saturated like that. Is it LED-lighting?
+1. It does look like a "narrow-band" = LED light source.
12-28-2013, 04:36 AM   #8
New Member




Join Date: Dec 2013
Location: Dortmund
Posts: 6
Original Poster
Hi VisualDarkness and Ex Finn.,

thanks for your input. Na Horuk and Jonathan feared that already, too. When I realize this during a photo session, is there a possibility to reduce this by using color filters on the lens? Or can this be post processed?

Na Horuk recommended "I suggest you shoot raw and play with the NR and color saturation+hue sliders, as well as White balance" - does that mean that you can do it on the cam or do it in a graphics program like PhotoShop or Gimp?

Regards,

Lutz


Last edited by lunany; 12-28-2013 at 04:39 AM. Reason: forgot idea from Na Horuk which goes the same direction like my idea
12-28-2013, 04:57 AM   #9
Pentaxian
VisualDarkness's Avatar

Join Date: Nov 2011
Location: Uppsala, Sweden
Photos: Gallery
Posts: 4,439
I would say that it's often impossible to make a technically great shot under these conditions. Either you burn out or hugely underexpose one or two color channels, it's a matter of priorities. Concert photographers face this dilemma all the time now with the modern LED lighting that is common now.

If you shoot RAW you can try to play with balance and the blue color channel to see if you can fix it somewhat without destroying the rest of the pic. At least you know that it's nothing you did wrong, it's a technical limitation.
12-28-2013, 06:54 PM   #10
Pentaxian
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 10,325
Photoshop, Lightroom, Gimp, Aperture, FastStone, Silkypix.. many of the raw editors will give you tools to cope with this. But with normal lights, even if there is a tint (like orange for regular bulbs) they still emit a relatively wide spectrum. So in post processing, you have the WB/white balance slider which solves most problems - the software can accurately guess what colours the objects actually are. You can play with colour channel curves or other more complicated things if WB fails you.
With LED lights its different - they have a very narrow spectrum, so your camera simply doesn't know what colours were there, except for the one that the LED light shined. And to compound the problem, that specific colour is very strong, highly saturated. There are blogs about the whole LED issue, you might want to google it in case they came up with anything. So far, there is no easy solution that I know of.
With complicated light scenarios like that, I just turn the photo black and white. That way, people don't mind some grain, and the distracting spacey colours are no longer stealing the focus from the intended subject. And if you use a raw software to turn a raw into BW, you can simply add blur or make some colours darker/brighter shades of grey. That is the beauty of raw - it gives you a lot of data and powerful tools to get the most out of your photos. But its not easy. Thankfully there are many tutorials on youtube and on websites.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-5 K-5 II K-5 IIs, e dial issue, Noise Eder Pentax K-5 17 06-03-2014 12:33 AM
New Firmware for K-500, K-50, K-5 II, K-5 IIs, K-5, K-30, K-01, K-r, and 645D is out Adam Pentax News and Rumors 60 09-16-2013 05:46 AM
K-5 IIs Screech Noise Matrishwa Troubleshooting and Beginner Help 17 03-11-2013 07:38 AM
Pentax K-x High noise, even at ISO 100 mpmetro Pentax DSLR Discussion 9 05-26-2012 11:17 PM
k-5 and k-r ISO noise higher than 3200? metungnasi Pentax K-5 14 12-11-2010 11:57 AM



All times are GMT -7. The time now is 12:03 AM. | See also: NikonForums.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