Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-30-2007, 02:29 AM   #1
Junior Member




Join Date: Feb 2007
Posts: 35
How do you test for damaged sensor? (Pentax K10d)

Regardless of lighting and/or ISO, dark colors on my pictures would come out really grainy (even ISO 100 or 200 at times!).

The problem looked really bad when looking back at pictures on the preview LCD and zooming in with the wheel, but doesn't appear AS bad when looking it on my computer (sample attached).

How can you test your sensor?

I unfortunately got some fine dust caught in my camera while I was in the Middle East (once my first "dusty" picture came out, I immediately went into a building and used the Rocket Blaster ... pictures were clear after that, but I'm scared it damaged the sensor - seems like reds come out overblown ever since... might just be me).

I'd appreciate any wisdom/advice/testing techniques form my fellow wise pentaxians :]

God bless,
Jon

Attached Images
 
11-30-2007, 02:30 AM   #2
Junior Member




Join Date: Feb 2007
Posts: 35
Original Poster
picture is compressed, so really hard to see - I'll try to post a better example soon, but any general advice still appreciated!
11-30-2007, 04:07 AM   #3
Veteran Member




Join Date: Aug 2007
Photos: Gallery
Posts: 1,563
QuoteOriginally posted by USCdeacon Quote
picture is compressed, so really hard to see - I'll try to post a better example soon, but any general advice still appreciated!
Why not add an enlarged crop of a particular area you can see the problem in.

- Bert
11-30-2007, 04:14 AM   #4
Pentaxian




Join Date: Sep 2006
Location: Kaunas
Posts: 1,452
QuoteOriginally posted by USCdeacon Quote
picture is compressed, so really hard to see - I'll try to post a better example soon, but any general advice still appreciated!
And post it with intact EXIF info. Your first picture is without EXIF info at all.

11-30-2007, 11:18 PM   #5
Senior Member




Join Date: Nov 2007
Location: Moscow, Russia
Posts: 239
Test is really easy. Turn up the sensitivity to 1600. Close the lens cap. Set the camera on the table, so it will not move, and then shoot one image in RAW.

Then go import the RAW file, and see it inch my inch. If should be black. Well, with some noise, yes, but mostly black. You'll see all dead pixels (if any), they will be bright blue. And all hot pixels (they will be most likely reddish).
11-30-2007, 11:35 PM   #6
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 9,545
Jon, what do you have your image quality set to?

1. Take a RAW shot and examine that. You cannot judge sensor quality from low res jpegs. If you can only use jpegs, set your jpeg to 10 Meg *** (High) quality.

2. Set your contrast, saturation and sharpness to 0 and examine the image.
12-01-2007, 03:12 AM   #7
Junior Member




Join Date: Feb 2007
Posts: 35
Original Poster
thanks for the quick replies!

I'll try it out sometime this weekend and post results (with EXIF intact
asap.
12-01-2007, 06:30 AM   #8
Veteran Member
mattdm's Avatar

Join Date: Feb 2007
Location: Boston, MA
Photos: Gallery
Posts: 2,964
QuoteOriginally posted by USCdeacon Quote
I unfortunately got some fine dust caught in my camera while I was in the Middle East (once my first "dusty" picture came out, I immediately went into a building and used the Rocket Blaster ... pictures were clear after that, but I'm scared it damaged the sensor - seems like reds come out overblown ever since... might just be me).
I think it's unlikely that dust permanently damaged the sensor -- the sensor itself is covered by a protective layer.

12-01-2007, 02:12 PM   #9
PDL
Pentaxian




Join Date: Oct 2006
Location: Woodinville, WA USA
Photos: Gallery
Posts: 1,175
It is important to also remember that the sensor - on DSLR's - is behind the shutter except during exposure. (Pentax DSLR's have a vertical travel focal plane shutter - just like their film SLR's)

However, with 'live view' the sensor will be exposed for extended periods and it will be charged --==>> dust magnet.

The Elitist - formerly known as PDL
12-02-2007, 08:04 AM   #10
Senior Member




Join Date: Nov 2007
Location: Moscow, Russia
Posts: 239
QuoteQuote:
However, with 'live view' the sensor will be exposed for extended periods and it will be charged --==>> dust magnet.
Yep, true. But Olympus made their dust removal technique extremely good. It really removes almost all, and people say that even constantly using LV they dont have to clean their sensor for years. So if someone did it, then it IS possible. Our (Pentax's) current dust removal is not even nearly that effective, but I hope that will change for the next camera, which is rumored to have LV.
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, dslr, iso, photography, pictures, sensor, test
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-r RAW Sensor Test From DxO Biro Pentax K-r 7 11-04-2010 01:09 AM
For Sale - Sold: Pentax-A* 300mm F4 (damaged) LightBug Sold Items 7 01-14-2010 01:05 PM
Damaged Pentax transfer cable dmadden Pentax DSLR Discussion 3 02-10-2008 02:06 PM
External flash test required for Pentax K10D jarnos Flashes, Lighting, and Studio 24 01-22-2008 08:34 PM



All times are GMT -7. The time now is 11:14 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