[Kcjacoby]

I've searched for noise issues, and I even posted up elsewhere about this issue. Someone suggested it was my K7 getting too warm... which... I've never ever heard to be an issue.

I recently came back from a trip to Hawaii, where I experienced some issues with my K-7. While shooting, I don't really stop and take a look at the review of the image... I just keep on plugging along. Once I brought the image back and uploaded it onto my computer, I noticed that ever 5th image has a horrible amount of ISO noise... Not just regular noise, but an abnormal amount that is making me wonder wtf...



I would be bracketing, and then 2 out of the 5 shots would have so much noise that they are un-useable.

I was thinking maybe a memory card issue, or just a bad transfer of data... but I'm completely baffled at this issue... and I'm rather upset because I've lost quite a few shots from Hawaii because of this.

Any idea?

[Kcjacoby]

Exif:

Camera: Pentax K-7
Exposure: 0.004 sec (1/250)
Aperture: f/11.0
Focal Length: 110 mm
ISO Speed: 250
Flash: Off, Did not fire

File Size: 9.0 MB
File Type: JPEG
MIME Type: image/jpeg
Image Width: 4684
Image Height: 3122
Encoding Process: Baseline DCT, Huffman coding
Bits Per Sample: 8
Color Components: 3
X-Resolution: 96 dpi
Y-Resolution: 96 dpi
Software: Picasa 3.0
Date and Time (Original): 2010:05:02 04:50:33
Metering Mode: Multi-segment
Focal Length In35mm Format: 165 mm
Image Unique ID: 9477f029f49748cbe3029ad3615b674a
Compression: JPEG (old-style)

[steve1307]

Looks like there might some "green banding" in there which I've never seen before to be sure about but have read about here and DPR with high sensor temperature.

What is the Firmware version K-7 1.00 ?

If you open the open the original JPEG file from the card in PHOTOME (not the posted one which has metadata altered by Picasa) this should give you the camera firmware and the camera temperature.

Firmware is also displayed on the LCD when you hold the MENU button down and switch on.

Underexposing makes the shot more noisy but I agree with your opinion, (on my uncalibrated monitor) that noise looks bad.

[philippe]

Heat is a real problem with digital captors, just like it was with pro. colour slide film at the time (excessive grain).
Two weeks ago, I was working around Gibraltar, where it was about 37°C. I had to shoot in full daylight on a tripod (K20d), for bracketing.
So the camera stood right in the sun and got really hot, so hot that the protective foil I sticked over the rear screen was loosening. So hot that the live view, witch usually stops after +/-5 to 7 min, when the sensor is warming up, could hardly be used, it shutted down about every 2 min.
Then I used a white tea cloth to cover up the camera and reflect the sun, a lot went better.
But, later on the computer, I saw that some shots, done before I covered the camera, were a little noisier than others, particularly the last one of the five exposures of the bracketing, all tough I was working all the time at 100 ASA and RAW/DNG.
Back home, I checked some info I had laying around, and figured out that heat might cause noise. Now, as I have to go back over there, my wife is sewing a kind of heat reflecting blimp to cover the camera, with velcro strips, as the tea cloth was carried away by the wind (Poniente).

[Jasvox]

Run your file through PhotoMe and see what the camera temperature was at time of shooting...


Jason

[Kcjacoby]

Alrighty... here's everything from Photo Me..

[PhotoME]
PhotoME version: 0.8ß2 (Build 891)

[Overview]
File name: C:\Documents and Settings\Owner\desktop\IMGP7568_3.jpg
File type: JPEG
File size: 13,202*KB
Creation date: 5/2/2010 00:50
Last modification: 6/17/2010 07:48
Make: PENTAX (PENTAX)
Camera: PENTAX K-7
Software: K-7 Ver 1.03
Dimension: 4672 x 3104*px*(14.5 MP, 3:2)
Focal length: 110*mm*(equiv. 165*mm)
Aperture: F11
Exposure time: 1/250" (-5*EV)
ISO speed rating: 100/21°
Program: Creative program (biased toward depth of field)
Metering Mode: Pattern
White Balance: Auto
Flash: Flash did not fire, compulsory flash mode

[IPTC-NAA data (IIM)]
Application Record Version: Version 2
Creator: Ken Jacoby
Copyright Notice: KcJacoby Photography

[JPEG]
Application Segment 1 (Exif): 0x00000006
Application Segment 13 (Photoshop): 0x00000270
Application Segment 2 (ICC*Profile): 0x00002710
Encoder: Adobe Lightroom, Quality: 85% - 92%
and maybe some other software or cameras
Encoder Signature: 42BFE52476BF07F1ED0E6451903CC9EE:111111
Color Mode: RGB color
Subsampling ratio of Y*to*C: YCbCr4:4:4
Encoding Process: Baseline DCT, Huffman coding
Bits per Sample: 8*bps
Image Height: 3104*px
Image Width: 4672*px
Number of image components in frame: 3*comp.

[Image]
Manufacturer: PENTAX
Image input equipment model: PENTAX K-7
Image resolution in width direction: 240*dpi
Image resolution in height direction: 240*dpi
Unit of X and Y resolution: inch
Software: K-7 Ver 1.03
File change date and time: 2010-06-17 07:48:07
Person who created the image: Ken Jacoby
Copyright holder: KcJacoby Photography
Exif IFD Pointer: 0x000000EE

[Camera]
Exposure time: 1/250"
F number: F11
Exposure program: Creative program (biased toward depth of field)
ISO speed rating: 100/21°
Exif version: 2.21
Date and time of original data generation: 2010-05-02 00:50:33
Date and time of digital data generation: 2010-05-02 00:50:33
Shutter speed: 7.97*Tv (1/250")
Aperture: 6.92*Av (F11)
Exposure bias: -5*EV
Metering mode: Pattern
Flash: Flash did not fire, compulsory flash mode
Lens focal length: 110*mm
Sensing method: One-chip color area sensor
Custom image processing: Normal process
Exposure mode: Auto bracket
White balance: Auto
Focal length in 35 mm film: 165*mm
Scene capture type: Standard
Contrast: Hard
Saturation: Normal
Sharpness: Hard
Subject distance range: Distant view

[Photoshop Image Resource Block]
X Resolution: 240*dpi
Displayed Units X: inch
??? (03ED): 1
Y Resolution: 240*dpi
Displayed Units Y: inch
??? (03ED): 1
IPTC Data: 0x00000028
New Windows Thumbnail: 0x00000064
IPTC Digest: 739B39BCD553804C7DD6CFC6D58C0B4F

[ICC Profile]
Profile CMM Type: Adobe CMM
Profile Version: 2.1.0
Profile Class: Display Device Profile
Data Color Space: RGB
Profile Connection Space: XYZ
Profile Date Time: 1999-06-03 00:00:00
Profile File Signature: "acsp"
Primary Platform: Apple Computer Inc.
CMM Flags: Not Embedded, Independent
Device Manufacturer: None
Device Model: Not set
Media Attributes: Reflective, Glossy, Positive Polarity, Color
Device Attributes: Not set
Rendering Intent: Perceptual
Connection Space Illuminant: [0.96420, 1.00000, 0.82491]
Profile Creator: Adobe Systems Incorporated
Profile ID: Not set
Profile Copyright: Copyright 1999 Adobe Systems Incorporated
Profile Description: Adobe RGB (1998)
Media White Point: [0.95045, 1.00000, 1.08905]
Media Black Point: [0.00000, 0.00000, 0.00000]
Red Tone Reproduction Curve: Curve is gamma of 2.2
Green Tone Reproduction Curve: Curve is gamma of 2.2
Blue Tone Reproduction Curve: Curve is gamma of 2.2
Red Matrix Column: [0.60974, 0.31111, 0.01947]
Green Matrix Column: [0.20528, 0.62567, 0.06087]
Blue Matrix Column: [0.14919, 0.06322, 0.74457]

[Kcjacoby]

You know what... I'm starting to believe this is the result of Picasa trying to 'remedy' a dark photo... even though I was shooting in bracketing... maybe I'm just seeint the actual noise for it being that underexposed...

[JohnBee]

You know what... I'm starting to believe this is the result of Picasa trying to 'remedy' a dark photo... even though I was shooting in bracketing... maybe I'm just seeint the actual noise for it being that underexposed...

If you were bracketing(exposure) then that makes plenty of sense

[Cuchulainn]

Umm, the photome shows that you have an exposure compensation of -5EV on that shot. That's the reason right there - you must have been bracketing at the time.

[MrPetkus]

Umm, the photome shows that you have an exposure compensation of -5EV on that shot. That's the reason right there - you must have been bracketing at the time.

The OP said he was bracketing...

[MrPetkus]

As an aside, every attempt at recording my daughter's birthday party last night in movie-mode on the K7 tanked after ~35 seconds due to overheating. Not in the scorching heat of exotic Hawaii or war-torn Afghanistan, but in my living room. I was sorely disappointed. Guess I'll use an HD camcorder next time...

[Kcjacoby]

As an aside, every attempt at recording my daughter's birthday party last night in movie-mode on the K7 tanked after ~35 seconds due to overheating. Not in the scorching heat of exotic Hawaii or war-torn Afghanistan, but in my living room. I was sorely disappointed. Guess I'll use an HD camcorder next time...

This is kinda alarming to me... I've never heard of a heat issue with the K-7... and now I find out about it after I bought it and have put my time and money into the gear.

*shrug*

I can't say I've ever had a problem like this with my K7 and I shoot in some pretty extrema condition and lighting. I does look like the images has been pushed too far by Picasa.

Do you have the original image as a comparison?

[MrPetkus]

This is kinda alarming to me... I've never heard of a heat issue with the K-7... and now I find out about it after I bought it and have put my time and money into the gear.

*shrug*

I knew about overheating - Googling + a quick error message description on page 306 of the K-7 manual. I seldom take video with my camera and wish I had tested the functionality before something important arose.

There is also the possibility that my unit is defective. I'd recorded a 15 minute movie with my past K-x without issue. I will be running my K-7 through a battery of tests later to determine what's going on.

Note that I've only experienced this in movie mode - never while bracketing or shooting in continuous drive.

[philippe]

I can't speak for Picasa, but as I shoot the over exposed one as the last, there is no problem due to compensating for deviating exposure, not in LR3 tough.
In the parts where there are mid-tones, there is noise. As I said, this nose went away by keeping the camera from warming op to much. This is my personal observation, but of course, I was shooting in the sun whole day's long, even at high noon (what I gate to do but…).