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Stu_F
30th March 2008, 09:10 PM
This is the first picture I have posted up here, so please be gentle. I took this photo last night. The picture has come straight from the camera with no processing

http://i65.photobucket.com/albums/h214/Stu_Fraser/P3291573.jpg
E-510, 14-142mm kit lens at 14mm, F22.0, ISO 100, 50 second exposure

Really pleased with how it has turned out apart from one thing. In the Hi-Res version you can see spots all over the image, these vary in colour from red, blue and white as can be sen in the enlarged section below

http://i65.photobucket.com/albums/h214/Stu_Fraser/Untitled1.jpg

Just wanted to know what is the cause of this? By the way the same spots are visible in the previous images taken on the camera in exactly the same positions :(

j.baker
30th March 2008, 09:17 PM
It appears that you have hot pixels.

Have you run pixel mapping? Its in your camera menu. Run this and see if your images improve.

Also, did you turn off noise reduction? If so, when you take long, +2 seconds, exposures you will normally see more hot pixels. When you enable the noise reduction the camera takes another shot of the same duration, but with the shutter closed. It then subtracts the blank image from the one it just took. This can reduce the image noise.

Ian
30th March 2008, 09:24 PM
This is the first picture I have posted up here, so please be gentle. I took this photo last night. The picture has come straight from the camera with no processing

http://i65.photobucket.com/albums/h214/Stu_Fraser/P3291573.jpg
E-510, 14-142mm kit lens at 14mm, F22.0, ISO 100, 50 second exposure

Really pleased with how it has turned out apart from one thing. In the Hi-Res version you can see spots all over the image, these vary in colour from red, blue and white as can be sen in the enlarged section below

http://i65.photobucket.com/albums/h214/Stu_Fraser/Untitled1.jpg

Just wanted to know what is the cause of this? By the way the same spots are visible in the previous images taken on the camera in exactly the same positions :(

As John says, that's a case of hot pixels and is probably normal. How long was the exposure? If it was several seconds, using Noise Reduction mode for long exposures will also help, but Pixel Mapping is the probably the best solution.

Ian

Nick Temple-Fry
30th March 2008, 09:26 PM
It appears that you have hot pixels.

Have you run pixel mapping? Its in your camera menu. Run this and see if your images improve.

Also, did you turn off noise reduction? If so, when you take long, +2 seconds, exposures you will normally see more hot pixels. When you enable the noise reduction the camera takes another shot of the same duration, but with the shutter closed. It then subtracts the blank image from the one it just took. This can reduce the image noise.


I agree with John, hot pixels and quite a lot of them, reducing image size almost always smoothes them over. Or you can clone them out in post processing - but it takes time. NR is great at eliminating most of them, at the cost of doubling the time it takes to create a shot.

Nice image though and a clever idea.

Nick

Stu_F
30th March 2008, 10:03 PM
Thanks for the quick reply folks. The image was taken with noise reduction off and I have not run pixel mapping yet. I will try running it and take some more pics with noise reduction on to see if that eliminates the hot pixels.

Ian, the exposure was 50 secs ;)

Thanks again

Stu

Ian
31st March 2008, 12:46 AM
Thanks for the quick reply folks. The image was taken with noise reduction off and I have not run pixel mapping yet. I will try running it and take some more pics with noise reduction on to see if that eliminates the hot pixels.

Ian, the exposure was 50 secs ;)

Thanks again

Stu

Oh yes :) You really do need pixel mapping (do it every six months) and NR on for exposures that long!

Ian

PeterD
31st March 2008, 01:18 AM
Nice shots Stu. How did you plan the exposure for this one?

You already have been given the advice on the 'spots'.

PeterD

Stu_F
31st March 2008, 12:28 PM
Nice shots Stu. How did you plan the exposure for this one?

You already have been given the advice on the 'spots'.

PeterD

Thanks Peter, not sure what you mean by planning the exposure, Im new to all this. I was just using the camera in shutter prority mode to see what effect different exposures had on the image ;)

PeterD
31st March 2008, 12:58 PM
Thanks Peter, not sure what you mean by planning the exposure, Im new to all this. I was just using the camera in shutter prority mode to see what effect different exposures had on the image ;)

Sorry to confuse Stu

I take it then that you took a number of exposures at different shutter speeds and this was the best of the bunch.

PeterD

Stu_F
31st March 2008, 01:20 PM
Sorry to confuse Stu

I take it then that you took a number of exposures at different shutter speeds and this was the best of the bunch.

PeterD

lol, no problem, yup, thats exactly what I did :cool:

E-P1 fan
31st March 2008, 02:24 PM
Sorry to temp hijack the thread - allied point -

Has any E-1 user successfully used the pixel mapping fuction on their camera?

Scapula Memory
31st March 2008, 03:29 PM
Sorry to temp hijack the thread - allied point -

Has any E-1 user successfully used the pixel mapping fuction on their camera?

Never seen the issue on any of my own long exposure pics though have used the PM feature. If you tap in the sequence of buttons to get the info screens I think it tells you how many pixels have been "sorted"

E-P1 fan
31st March 2008, 03:42 PM
John how long did it take to do the mapping?

Scapula Memory
31st March 2008, 04:06 PM
Not very long at all, a matter of seconds from what I remember. The manual suggests to do it annually.

E-P1 fan
31st March 2008, 04:48 PM
you sure it wasn't manually :)

the reason I asked - someone told me they tried it and it took forever - so I've never done mine:o

Invicta
31st March 2008, 05:12 PM
Handy tip on the pixel mapping, I have erred away from it in the past as I did not full understand it.

Just run pixel mapping on my E-3 and it took only a few seconds.

E-P1 fan
31st March 2008, 09:47 PM
Aha - a case of my over-caution I think :) OK will give it a go and repoirt back here so anyone else in the future can be re-assured :)

AdrianD
1st April 2008, 12:21 PM
I have had the same problem with a shot of 1 min, full of red and blue points and someone tell me to use Mediachance HotPixel its e free program that "erase" this hots pixels, may be you need 3 or four pass but does the job

E-P1 fan
1st April 2008, 01:33 PM
Aha - a case of my over-caution I think :) OK will give it a go and repoirt back here so anyone else in the future can be re-assured :)

Huh well that took all of 5 secs :)

Scapula Memory
1st April 2008, 01:37 PM
Huh well that took all of 5 secs :)

Now it will probably be 12 months before you go on that roller coaster ride again :D

E-P1 fan
1st April 2008, 01:51 PM
Oh a few more years than that John. Only so much stress I can take *chr