Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old May 2, 2005, 8:03 AM   #11
Senior Member
 
Catbells's Avatar
 
Join Date: Nov 2004
Posts: 874
Default

Good advise, but for a camera just 2 weeks old, I'd return it under warranty for replacement.
Catbells is offline   Reply With Quote
Old May 2, 2005, 8:17 AM   #12
Senior Member
 
errno_gmm's Avatar
 
Join Date: Feb 2005
Posts: 518
Default

I agree, doesnt sound good and it should be replaced. However, I had a great though. The custom settings. So I checked them, the very first one: Noise reduction. Set it to off, and take a 30 second exposure, immediately saved, no probs. Here is a picture to demonstrate the difference on a 10s exposure, between complete default settings and custom setting with noise reduction off. I cant notice any difference at all, and if it does become a problem (maybe at even longer shutters) there are plenty of free noise reduction programs out there. Photoshop is fine if you know what you are doing. I even found a free one written in Java (very slow, but it works quite well)

Anyway here is the pic. 100% crop. Saved at (7) Jpeg quality in PS, hopefully it doesnt kill it. Only way to make it the 250k file limit (who thought of such a low limit on a photo board) Anyways.

Attached Images
 
errno_gmm is offline   Reply With Quote
Old May 2, 2005, 8:21 AM   #13
Senior Member
 
errno_gmm's Avatar
 
Join Date: Feb 2005
Posts: 518
Default

Ah, looking just now I see one 3 hotpixels in total, a green one down near the chair leg, and 2 blue ones, one over the left of the image and one at the bottom. Hardly worth the wait of the time of the exposure to remove 3 pixels that would take less than 2 minutes in any image editing program. Ill have to go test it with some lightning that im hoping will happen tonight
errno_gmm is offline   Reply With Quote
Old May 2, 2005, 8:26 AM   #14
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

errno_gmm wrote:
Quote:
I agree, doesnt sound good and it should be replaced. However, I had a great though. The custom settings. So I checked them, the very first one: Noise reduction. Set it to off, and take a 30 second exposure, immediately saved, no probs. Here is a picture to demonstrate the difference on a 10s exposure, between complete default settings and custom setting with noise reduction off.
If you scroll up above the e in the word Reduction (in your "No Noise Reduction" text), you'll see a hot pixel.

Dark Frame Noise Reduction is designed specifically for this type of problem (and you'll probably see even more hot pixels on longer exposures, and/or when CCD temperature increases). Since thesame pixel would have been hot in the dark frame exposure, itknows where to find it in your actual exposure. It then replaces it in the actual exposure by interpolating values from adjacent pixels.

As for Noise Reduction Software, most are not designed to handle hot pixels very well. A Dark Frame based system is usually preferrable for this problem (and some Noise Reduction Software products have the ability to use a dark frame if you supply one).

Edit: I didn't see your response before posting this one. LOL I noticed the one with a quick glance (and I see you found more).

This can be a huge problem with some images (longer exposures, especially when the camera is hot). Fortunately, most modern digital cameras have this type of system to minimize the effect.
JimC is offline   Reply With Quote
Old May 2, 2005, 9:20 AM   #15
Senior Member
 
ennacac's Avatar
 
Join Date: Mar 2005
Posts: 4,198
Default

How fast is the SD card you are using, as I find that when I use a regular Lexar card the write times are much longer than when I use a 60x Lexar card.

Possibly the card you are using is too slow to keep up with all that is going on with the long exposure.

Tom
ennacac is offline   Reply With Quote
Old May 2, 2005, 11:36 AM   #16
Senior Member
 
errno_gmm's Avatar
 
Join Date: Feb 2005
Posts: 518
Default

I am using only a 32x 256mb lexar card. Write time is pretty much instant once i turn off that noise reduction setting
errno_gmm is offline   Reply With Quote
Old May 2, 2005, 7:45 PM   #17
KSV
Senior Member
 
Join Date: Jan 2005
Posts: 248
Default

mgarula wrote:
Quote:
I get an I/O error. The PC responds that the card is not formatted. I'm wondering is after a minute of CCD activity, 30 secs for exposure, 30 secs for Hot Pixel Correction, if the NiMh batteries are writing at a lower voltage. If they are writing 1's at only slighly over VOH, and a similar system would be the 0's may not be discharged to below VOL. If the data is read in the camera using a differential circuit aprouch the data may still be intack when read from the PC, but the data coupling to the PChostis degraded,
Have tried with mine, 20 sec exposure (+ 20 sec noise reduction :-) ), writing time (when SD LED flashing) is negligible and files are readable by my card reader without and problem. Probably you right about voltage (however I am using NiMhas well), or probably there is something about your SD card compatibility with card reader or probably combination.
KSV is offline   Reply With Quote
Old May 3, 2005, 2:09 AM   #18
Senior Member
 
Catbells's Avatar
 
Join Date: Nov 2004
Posts: 874
Default

errno_gmm wrote:
Quote:
I am using only a 32x 256mb lexar card. Write time is pretty much instant once i turn off that noise reduction setting
I've used both 'standard' write (PNY)& x60 (Integral) with no difference in write speed.

Either the PNY was faster than specified, the Integral was slower or the *istDS just writes at 1 speed.
Catbells is offline   Reply With Quote
Old Oct 6, 2005, 6:39 PM   #19
Junior Member
 
Join Date: Oct 2005
Posts: 4
Default

I've seen others report that ist DS writes at around 45X. So 60X or faster cards just up the safety/reliability factor but not actual speed.
oxford_don is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 10:23 AM.