First gen Dp2 sensor problem?

So it was just one picture and the battery (and card) had bee in the camera unused for quite some time? Have you recharged the battery? If you have and it is not reoccurring, I would not worry about it. Those batteries drain whether in or out of the camera.

R

It could be a combination of the battery being low, or even perhaps the sensor not having been used for a while and all the electronics needing a little warm-up. I wouldn't worry about it unless it starts happening more regularily.

after taking that picture, I put on a new battery and had the camera on standby (liveview). i noticed blurred magenta patch on the bottom side of the screen. I hand held the camera and pointed it to the window where the light was coming in from and it disappeared. I pointed it on my laptop and on my desk and the half of the screen is in magenta. I pointed it back on the window, disappears and again on the laptop it appeared.

After that, I took the camera outside and started shooting, so far the magenta patch or cast did not appear. i'll investigate further since based on that crude "Testing" it appears to occur in low light scenarios ( i am not sure). Hopefully its nothing because if it is, then my trip is done T_T considering that the idea of the trip is a photo trip starring dp1s and dp2 T_T

Don't underexpose ISO 50

jozhua said:

after taking that picture, I put on a new battery and had the camera on standby (liveview). i noticed blurred magenta patch on the bottom side of the screen. I hand held the camera and pointed it to the window where the light was coming in from and it disappeared. I pointed it on my laptop and on my desk and the half of the screen is in magenta. I pointed it back on the window, disappears and again on the laptop it appeared.

After that, I took the camera outside and started shooting, so far the magenta patch or cast did not appear. i'll investigate further since based on that crude "Testing" it appears to occur in low light scenarios ( i am not sure). Hopefully its nothing because if it is, then my trip is done T_T considering that the idea of the trip is a photo trip starring dp1s and dp2 T_T

Click to expand...

Er, what is "T_T"?

Your camera LCD liveview is a fast sRGB conversion from the sensor signals and has to be fast so you can wave the camera around in real time. Fast means that the conversion is not of the finest multi-algorithm process, unlike SPP for example. Furthermore, it may even use simple multipliers for the liveview WB. All of which means that, at low light levels, there could be color artifacts in the live view that don't look good, especially if the WB is incorrect or the AWB performs poorly for the viewed scene.

So, how does the raw image preview look in SPP? Just as bad?

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Cheers,
Ted

xpatUSA said:

Er, what is "T_T"?

Click to expand...

Tears running down face supposedly.

I am happy to report that after using the camera for quite some time, the magenta lines and cast have gone away. I did however find the same on a picture prior to this post which means that it happened before. I could only see one photo though so i guess it is nothing to be worried about.

with regards to the raw file, yeah its bad, the lines can be seen. here's the previous picture



Its not a good shot i know but just to show the lines and that they are present.

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Jozhuaamahitphotography.blogspot.com - My world through the lens of a Sigma camera.

jozhua said:

I am happy to report that after using the camera for quite some time, the magenta lines and cast have gone away. I did however find the same on a picture prior to this post which means that it happened before. I could only see one photo though so i guess it is nothing to be worried about.

with regards to the raw file, yeah its bad, the lines can be seen.

Click to expand...

I did notice in the doggie pic that the settings were 50 ISO and -1/3EV. Your camera is pre-AFE (analog front end) which means that the raw data does not change with ISO setting. In turn, that means your image headroom is reduced because SPP that applies a factor based on the selected ISO. (the selected ISO is passed to SPP, or the in-camera JPEG engine, as a number; the raw data is not altered).

That may be hard to follow, so here is a theoretical example:

Let's say the sensor records a gray scene such that the average raw value is 1024. At 100 ISO, the theoretical RGB values will be 64 (1024/4096x256). At 200 ISO the values will be 128. At 400 ISO they would be 256 which will get clipped to 255.

Next, by selecting or shooting at -1/3EV your actual sensor exposure will be reduced by a factor of 1.26 - thus, what would have been a raw value of 1024 becomes 812.

At 50 ISO, the RGB value would halved by SPP. i.e. 1024 gives 32 and your actual exposure-compensated or under-exposed 812 gives RGB = 25 which is quite dark for a scene that started out only -2EV (approx) ends up as -3-1/3EV in your image.

Sorry, probably too much information.

A suggestion would be to shoot the dog ;-) at 0.00 EV comp and 50, 100, 200 ISO.

Compare shots and look for lines. Either 50 ISO will be worse than 200 - or vice-versa.

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Cheers,
Ted