IQ260 processing hot pixel LR vs C1

[yatlee]

Left side is Lightroom 5, Sharpness = 0, Noise reduction = 0, Color Temp = "As Shot" (in short, everything set to 0)

Right side is Capture One, Sharpness = 0, Noise reduction = 0, LCC Profile = "IQ260 Outdoor Daylighe", Curve = "Film Standard" (in short, everything set to 0)

I see something strange here. The hotpixel is clearly an issue which seems taken care of by C1. However, it also alter the look the image.

1. some of the traffic lights are gone as well or random color (red, purple on the window and street lights) are added to the C1 processed image.
2. the building on the right looks worse/soft on the C1.

Has anyone experience this? I do like the look of the LR image except for the hot pixel in the sky.

Screen Shot 2014-07-14 at 5.35.25 pm by By Yat Lee, on Flickr

 

[tcdeveau]

That exposure was only 30 secs, correct? I'm surprised to see that hot pixels are that prevalent. I would like to upgrade to something like an IQ260 in the future but if hot pixels are an issue that's kinda worrisome. I've never used C1, but I just went through a round of hot pixel correction myself, and found that the noise filter at even just 1 pixel with Photoshop softened the buildings in the distance pretty bad

 

[iiiNelson]

Without getting into a C1 v. LR debate, the bigger question is can you process the image in each RAW converter to achieve the look you desire. If the answer is yes, then the simple answer is to go with the RAW convertor you prefer to use. No one will really leave the RAW unprocessed but it wouldn't surprise me if C1 gave the best results with Phase products.

 

[dougpeterson]

Capture One looks at and uses the dark frame information recorded by the digital back into the raw file. LightRoom does not.

I'd need to see a raw file to comment further on exact best raw processing settings. Looks to me like color noise reduction is too low (for my taste) on the C1 image, but without the raw couldn't say for sure. Keep in mind that when you set "0" on noise reduction in different programs the meaning is not necessarily the same. Capture One, with color noise reduction set to 0, is going to give you very honest results about the demosaic'd image's imperfections. Also, the color noise reduction slider in C1 will also effect single-pixel noise when those pixels are of a specific/strong color. So the valid/meaningful comparison is not with both programs set to zero on everything, but with each program tweaked the best you can manage.

Feel free to post a raw file or send it to me by email if you want more informed replies. If you do, please post what exact version of C1 you are using is.

 

[dougpeterson]

That exposure was only 30 secs, correct? I'm surprised to see that hot pixels are that prevalent. I would like to upgrade to something like an IQ260 in the future but if hot pixels are an issue that's kinda worrisome. I've never used C1, but I just went through a round of hot pixel correction myself, and found that the noise filter at even just 1 pixel with Photoshop softened the buildings in the distance pretty bad

When it comes time, just make sure you test it in both C1 and LR so you know what the possibilities are . The fact that LR does not use the dark frame data is a severe handicap it it's handling of long exposure files from these backs.

Also the 260 has both a long-exposure (LE) mode and a none LE mode. Each produces a distinctive look and noise profile. Having it on means slightly higher grain, but far fewer single-pixel noise issues.

 

[Paul2660]

Also the 260 has both a long-exposure (LE) mode and a none LE mode. Each produces a distinctive look and noise profile. Having it off means slightly higher grain, but far fewer single-pixel noise issues.

Doug:

You lost me on this. as with the 260, Phase One recommended the long exposure mode for any exposures longer than 1 or 2 seconds, at least the back continuously prompts you to move to LE mode when taking a 2 or 6 second exposure.

I have always thought that the LE mode would produce less stuck pixels by design, as it's meant for exposures longer than 60 to 90 seconds?

So by design? does using the 260 for a "long" exposure generate stuck pixels that can't be removed? by long exposure lets say 30 minutes. or even 15 minutes. I also thought that the mandatory dark frame was used in part to map out the "stuck pixels". Or should 15 to 1 hour exposures be taken in normal mode?

What is the best practice for a long exposure with a 260? besides staying within the outdoor temp limit of 69 degress F and low humidity?

Back to the OP, LR IMO doesn't do well with stuck pixels on any camera raw file. C1 seems to have a better solution with the "single pixel noise" reduction slider. In my night photography with Canon and Nikon with 2 and 3 minute exposures on warmer nights, both camera will start to generate stuck pixels and since I turn off "long exposure noise reduction" due to the fact it stops the camera from shooting (with stacking night exposures) it's very important to be able to remove as many of them as possible. Canon and Nikon both map out stuck pixels in their dark frames when it's turned on. I have always assumed so did Phase One.

Thanks
Paul

 

[yatlee]

Hi all, the raw file can be downloaded here.

https://docs.google.com/file/d/0B9QoNLxWMTzETjgzWXM3a1VuNkk/edit

 

[ondebanks]

Capture One looks at and uses the dark frame information recorded by the digital back into the raw file. LightRoom does not.

Are you sure about that? The LR version also shows a lot of single black pixels, which to me always indicates that a dark frame has been subtracted ...saturated hot pixels in both the original image and dark frame cancel to zero in intensity.

Or do you mean something different by "uses the dark frame information" - something other than subtraction?

Ray

 

[Morpheus]

Sorry the RAW file in google drive was protected from download. Now I have changed the permission access. Anyone can download it now.

Morpheus

 

[voidshatter]

Are you sure about that? The LR version also shows a lot of single black pixels, which to me always indicates that a dark frame has been subtracted ...saturated hot pixels in both the original image and dark frame cancel to zero in intensity.

Or do you mean something different by "uses the dark frame information" - something other than subtraction?

Ray

In many raw files I have discovered that Lightroom cannot utilize the darkframe data of the Phase One digital backs.

 

[voidshatter]

Doug:

You lost me on this. as with the 260, Phase One recommended the long exposure mode for any exposures longer than 1 or 2 seconds, at least the back continuously prompts you to move to LE mode when taking a 2 or 6 second exposure.

I have always thought that the LE mode would produce less stuck pixels by design, as it's meant for exposures longer than 60 to 90 seconds?

So by design? does using the 260 for a "long" exposure generate stuck pixels that can't be removed? by long exposure lets say 30 minutes. or even 15 minutes. I also thought that the mandatory dark frame was used in part to map out the "stuck pixels". Or should 15 to 1 hour exposures be taken in normal mode?

What is the best practice for a long exposure with a 260? besides staying within the outdoor temp limit of 69 degress F and low humidity?

Back to the OP, LR IMO doesn't do well with stuck pixels on any camera raw file. C1 seems to have a better solution with the "single pixel noise" reduction slider. In my night photography with Canon and Nikon with 2 and 3 minute exposures on warmer nights, both camera will start to generate stuck pixels and since I turn off "long exposure noise reduction" due to the fact it stops the camera from shooting (with stacking night exposures) it's very important to be able to remove as many of them as possible. Canon and Nikon both map out stuck pixels in their dark frames when it's turned on. I have always assumed so did Phase One.

Thanks
Paul

According to my tests, LE mode is definitely better than normal mode for exposures longer than 10 seconds. With LE mode off, aliasing and artifacts start to appear pretty soon.

 

[dougpeterson]

Oops! I said "off" where I should have said "on" in my pose regarding "LE mode". Sorry Paul. I've corrected it.

The difference a word can make!

 

[Paul2660]

Doug

Thanks. I was hoping that was a typo.

Paul

 

[ondebanks]

Are you sure about that? The LR version also shows a lot of single black pixels, which to me always indicates that a dark frame has been subtracted ...saturated hot pixels in both the original image and dark frame cancel to zero in intensity.

Or do you mean something different by "uses the dark frame information" - something other than subtraction?

Ray

Doug, can you please follow up on this?

I was thinking further about this and the underlying question is - what is the format of the IIQ RAW file - what's actually inside it? Is it:
1) the unaltered original RAW image, + the dark frame which followed it?
2) the dark-subtracted RAW image, + the dark frame which was subtracted from it?
3) the unaltered original RAW image, + something else derived the from dark frame (such as a hot pixel mask) but not actually the full dark frame?
4) the dark-subtracted RAW image, + something else derived the from dark frame (such as a hot pixel mask) but not actually the full dark frame?

My original suspicion on seeing the crop of yatlee's image above was that it's number 4): LR sees only the dark-subtracted image but it's imperfect because the sensor temperature keeps rising as it moves on to take the dark frame; while C1 is using some sort of derived warm/hot/saturated pixel mask to zap out and interpolate across remaining problem pixels (both bright and dark) in the the dark-subtracted image.

However, having downloaded and played with his full IIQ raw file in RawTherapee with everything (including demosaicing) off, I'm now of the view that it's probably number 1). There is just way too much dark noise for the image to have been dark subtracted already - a mere ISO 50 at 30 seconds could not possibly look so bad after dark subtraction.

However, that conclusion invokes a new mystery - why are there all those black/dead pixels in the RAW image, if there's been no dark subtraction yet?

Anyway, until we know the authoritative answer about what's really in the IIQ file, we're just guessing in the dark (pun intended!) about what's going on in the different RAW converters. I would really like to know what the official story is.

Thanks,
Ray

 

[Paul2660]

A few more thoughts on the shot.

1. The exposure was taken at 30 seconds, so a mandatory dark frame followed the exposure. All Phase One backs do this, and if you kill the camera before the dark frame finished, the exposure is not recorded. So for this shot, @ iso 50, there is dark frame information.

2. I have never known exactly what is recorded in Phase One dark frame, noise/stuck pixels or just noise. It would be nice to know that and if during the recording of dark frame, is any mapping done, like with a Canon or Nikon camera CMOS. You can visually see a difference especially with stuck pixels when either of these cameras is in long exposure noise reduction mode. I have always found Phase shots seem to hold some more of the stuck pixels, but the single pixel noise slider in C1 always will remove them without a lot of detail loss

3. The OP stated that he opened the images with "no" noise reduction on, and with C1, by default there is some noise reduction loaded with the file. With normal iso 50 shots (not longer exposures like this one) I have always felt that C1 has a bit too much noise reduction in the default settings.

4. What was the outside temp and how long was the back on before this shot, and did you shoot a shot to clear the pixels wells. I been told that if you are shooting a lot of exposures longer than say 2 seconds, that it's a good idea to take one shot a around 1/500 of sec, just to clear out stuck pixels. This is a trashed shot, no need to keep it as it will grossly underexposed.

5. I don't feel LR can use the dark frame info from Phase cameras and for that matter LR 5.4 or 4.3 handle stuck pixels very well on a Canon or Nikon camera shot with LEND (long exposure noise reduction) off. These cameras I believe apply the info to the file inside the camera as you can view the file on the camera LCD and see a significant reduction in stuck pixels. It's a simple test, just take 3 minute exposures 1 with LEND on and 1 without, then compare them.

6. Since the OP was at base iso 50, he was not able to use the LE mode of the 260, and it would have been a good test to clear the pixels, and shoot another 30 second shot at iso140 in LE mode for a comparison. Hopefully the OP can do that at a later date. I plan to do it with my 260 in the next few days just to see what I get.

Paul

 

[Morpheus]

A few more thoughts on the shot.

1. The exposure was taken at 30 seconds, so a mandatory dark frame followed the exposure. All Phase One backs do this, and if you kill the camera before the dark frame finished, the exposure is not recorded. So for this shot, @ iso 50, there is dark frame information.

2. I have never known exactly what is recorded in Phase One dark frame, noise/stuck pixels or just noise. It would be nice to know that and if during the recording of dark frame, is any mapping done, like with a Canon or Nikon camera CMOS. You can visually see a difference especially with stuck pixels when either of these cameras is in long exposure noise reduction mode. I have always found Phase shots seem to hold some more of the stuck pixels, but the single pixel noise slider in C1 always will remove them without a lot of detail loss

3. The OP stated that he opened the images with "no" noise reduction on, and with C1, by default there is some noise reduction loaded with the file. With normal iso 50 shots (not longer exposures like this one) I have always felt that C1 has a bit too much noise reduction in the default settings.

4. What was the outside temp and how long was the back on before this shot, and did you shoot a shot to clear the pixels wells. I been told that if you are shooting a lot of exposures longer than say 2 seconds, that it's a good idea to take one shot a around 1/500 of sec, just to clear out stuck pixels. This is a trashed shot, no need to keep it as it will grossly underexposed.

5. I don't feel LR can use the dark frame info from Phase cameras and for that matter LR 5.4 or 4.3 handle stuck pixels very well on a Canon or Nikon camera shot with LEND (long exposure noise reduction) off. These cameras I believe apply the info to the file inside the camera as you can view the file on the camera LCD and see a significant reduction in stuck pixels. It's a simple test, just take 3 minute exposures 1 with LEND on and 1 without, then compare them.

6. Since the OP was at base iso 50, he was not able to use the LE mode of the 260, and it would have been a good test to clear the pixels, and shoot another 30 second shot at iso140 in LE mode for a comparison. Hopefully the OP can do that at a later date. I plan to do it with my 260 in the next few days just to see what I get.

Paul

I am the original shooter. I can answer some of your questions.

For question 4, outside temp is around 30 degree C (86 degree F), and the back was on for around half an hour. Before this shot, I didn't shoot a shot to clear the pixels wells.

For question 6, I did test iso140 in LE mode (with 2 F stop down) after this shot (but at a different location). The result is that LE mode produces much much cleaner result.

I also did take a shoot a while ago at outside temp around 5 degree C (41 degree F), iso50, LE mode off, 30 seconds. The result was much better than this 30 degree C outside temp shot, although still not cleaner than iso140 LE mode on.

Morpheus

 

[dougpeterson]

I am the original shooter. I can answer some of your questions.

For question 4, outside temp is around 30 degree C (86 degree F), and the back was on for around half an hour. Before this shot, I didn't shoot a shot to clear the pixels wells.

For question 6, I did test iso140 in LE mode (with 2 F stop down) after this shot (but at a different location). The result is that LE mode produces much much cleaner result.

I also did take a shoot a while ago at outside temp around 5 degree C (41 degree F), iso50, LE mode off, 30 seconds. The result was much better than this 30 degree C outside temp shot, although still not cleaner than iso140 LE mode on.

Morpheus

That context is much appreciated!