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IQ3 100MP long exposure issue - shadow filled with red color cast

I did not test for what happens if you take a short exposure and try to use that dark frame for a long exposure. I don't see why someone would do that. Presumably a photographer knows when she/he is going to do long exposures, so in preparation, with the knowledge that the first dark frame in Aerial mode will be used for all subsequent shots, the photographer would take a "typical" long exposure frame as the first frame so a roughly relevant dark frame would be used. This is one of the things I learned (thanks Doug!). If I ever go out shooting long exposures, and don't want to wait for a dark frame, then my first image in Aerial mode will be a long exposure. I could do that while driving to the site!

Dave
I can't agree with this ;)

Having the flexibility to choose different exposure times ranging between 2~16 minutes is an essential function for a CMOS back. Cloud can move at different speeds, and light condition changes over time during sunrise/sunset, not to mention the battery and heat restrictions. If the IQ3 100MP doesn't support this while the IQ250 and the other smaller sensors can then it's gonna be a huge draw back for me. I have never shot preliminary darkframes with the IQ250/D810A/D800E before.

Now that's just darn funny.
:LOL:
If you have time please test the underexposed lightframes and help me fill in the table! :cool: But I'll test that with another demo unit in about a week anyway.
 
I can't agree with this ;)

Having the flexibility to choose different exposure times ranging between 2~16 minutes is an essential function for a CMOS back. Cloud can move at different speeds, and light condition changes over time during sunrise/sunset, not to mention the battery and heat restrictions. If the IQ3 100MP doesn't support this while the IQ250 and the other smaller sensors can then it's gonna be a huge draw back for me. I have never shot preliminary darkframes with the IQ250/D810A/D800E before.

If you have time please test the underexposed lightframes and help me fill in the table! :cool: But I'll test that with another demo unit in about a week anyway.
Could you please show us a real life image? It would be interesting to see the photography series or project you are working on. Just to be clear, it involves extreme under exposure, shooting in aerial mode and lifting the shadows 100% in capture one?

Thank you,
Jeffery
 

dchew

Well-known member
Quick note... what you are doing is not technically "disabling" the dark frame. You are forcing the back to reuse the dark frame made in the first capture executed after enabling the aerial mode.
One note on this. What actually happens with my back (4.01.2) is: Turn on the back, go to Aerial / zero latency mode. First frame takes a dark frame, subsequent frames do not. But if instead I turn on the back in "normal" mode, shoot a frame, switch to Aerial / zero latency mode without cycling power, then shoot a frame, there will be no dark frame in that first Aerial-mode capture. If I turn the back off with it in Aerial mode then turn it back on, the first frame taken after cycling power will take another dark frame.

This was giving me fits yesterday because it would sometimes take a dark frame when I had not switched back and forth from Aerial mode. It was because I had cycled power when removing the CF card.

So switching to Aerial mode is not what triggers that first dark frame. It is instead cycling power on the back. If you have the back turned on and shoot a frame in normal mode, then switch to Aerial mode and take another frame without cycling power, there will be no dark frame on that first "Aerial" capture.

A better way to describe how this works: When in Aerial mode / zero latency, the back will not shoot a dark frame unless it is the first capture executed after cycling power.

Dave
 
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Could you please show us a real life image? It would be interesting to see the photography series or project you are working on. Just to be clear, it involves extreme under exposure, shooting in aerial mode and lifting the shadows 100% in capture one?

Thank you,
Jeffery
I have posted many, again and again. For example, this was a picture I made for a photography magazine cover:

71-2.jpg

Why under exposure and lifting the shadows 100%: It is required to protect the highlight details.

Why aerial mode: the flexibility to shoot a series of long exposure images without any breaks is essential to maximize success chance throughout a limited time window e.g. sunset/sunrise (and doubles success chance compared against those requiring darkframe NR countdown).

Backlight long exposure is my favorite because it stresses sensor most and is not easy for ordinary sensors and hence not easy to shoot. You could follow my pictures at https://500px.com/voidshatter
 

dchew

Well-known member
But Yunli, that's not a 20 min exposure.

Dave
I should explain myself... I see the need to push shadows dramatically in a high DR image like you post. I also understand the need to take 20 min exposures, both for cloud movement and for astro. But I struggle with the need for both together.
 
But Yunli, that's not a 20 min exposure.

Dave
8 minutes: https://500px.com/photo/152480667/

7 minutes: https://500px.com/photo/103108753/ (but no need to push shadow in this one)

8 minutes of stacking: https://500px.com/photo/92579427/ (so it was not possible to allow darkframe NR countdowns)

10 minutes: https://500px.com/photo/79511091/ (dynamic range of CCD is not so good when compared against D800E etc)

2 hours of suntrail: https://500px.com/photo/67886275/ (published in another photography magazine)

2.5 hours of suntrail: https://masterv.tuchong.com/6920849/ (taken by one of my friends)
 
I should explain myself... I see the need to push shadows dramatically in a high DR image like you post. I also understand the need to take 20 min exposures, both for cloud movement and for astro. But I struggle with the need for both together.
I have received another update from my friend - even if he properly expose his shots he still gets the red cast. This means

a) Your red darkframe and the demo unit's red darkframe do not necessarily mean these two copies of IQ3 100MP would get caught by red cast for real-world images;

b) It is unknown whether these two copies of IQ3 100MP would get caught by red cast for underexposed images but for now I don't think they will;

c) It is highly likely that the red darkframe is not associated with my friend's red cast images, and that his back alone is caught by the red cast images.

I'll find this out next week when I have access to another demo unit :)
 
I have posted many, again and again. For example, this was a picture I made for a photography magazine cover:
Thank you Void. Good luck with your project. I'm not sure if and when I will utilize your way of shooting, but it's always nice to have an extra tool in the visual kit.

Jeffery
 

dchew

Well-known member
This picture IS LOOK very sharp :lecture:

I can steal by cropping out the pictures inside this picture (the forest covered by snow in the frame in the top left corner) to make money :LOL:

(I'm just kidding)
That's my brother's back yard in Alaska.
:thumbup:
 

Pradeep

Member
8 minutes: https://500px.com/photo/152480667/

7 minutes: https://500px.com/photo/103108753/ (but no need to push shadow in this one)

8 minutes of stacking: https://500px.com/photo/92579427/ (so it was not possible to allow darkframe NR countdowns)

10 minutes: https://500px.com/photo/79511091/ (dynamic range of CCD is not so good when compared against D800E etc)

2 hours of suntrail: https://500px.com/photo/67886275/ (published in another photography magazine)

2.5 hours of suntrail: https://masterv.tuchong.com/6920849/ (taken by one of my friends)
Yunli, Thanks for posting these links, the pictures are indeed very nice.

I am intrigued by the method you describe in the second image (60 shots in rapid succession). How do you adjust for the movement of the sun in this time period? Even at 8 second duration, it takes almost 8 minutes to complete the shoot during which the sun would move significantly. Do you mask it out and only stack the shadows? If you do that, as the sun moves, the shadows too would move, as would the reflections on the water.

Thanks in advance.
 

dougpeterson

Workshop Member
I have received another update from my friend - even if he properly expose his shots he still gets the red cast. This means

a) Your red darkframe and the demo unit's red darkframe do not necessarily mean these two copies of IQ3 100MP would get caught by red cast for real-world images;

b) It is unknown whether these two copies of IQ3 100MP would get caught by red cast for underexposed images but for now I don't think they will;

c) It is highly likely that the red darkframe is not associated with my friend's red cast images, and that his back alone is caught by the red cast images.

I'll find this out next week when I have access to another demo unit :)
Definitely sounds like it's time for your friend to submit Raws to a support case through their dealer. They can help you/him troubleshoot to find the variable responsible.
 

Christopher

Active member
Yes and before doing that I still would like to see a XF/DF image from that back. As my guess is still rech camera problem.
 
How do you adjust for the movement of the sun in this time period? Even at 8 second duration, it takes almost 8 minutes to complete the shoot during which the sun would move significantly. Do you mask it out and only stack the shadows? If you do that, as the sun moves, the shadows too would move, as would the reflections on the water.
Hi, I did not specifically process the sun. 8 minutes are not long enough to leave an obvious sun trail. With the basic stacking the overexposed regions may get averaged down by other frames in which the same region was not overexposed.

Indeed if this stacking method is used to shoot a sun trail then luminosity masks are required for each frame to make sure the sun trail does not get averaged down. Apperantly a camera with compulsory darkframe NR will not be suitable for this kind of job.

Definitely sounds like it's time for your friend to submit Raws to a support case through their dealer. They can help you/him troubleshoot to find the variable responsible.
Not yet Doug. I have just received more feedback from my friend, as well as from Dave. It may be more complicated than we thought. Further tests may swing this and it's probably gonna be Phase One's responsibility to fix it for perhaps more than one IQ3 100MPs. :loco: I'm still in the process of collecting as much data as possible and trying to get some consistent results for Phase One to reproduce this problem reliably, and hence results from multiple users can be very helpful to me.

Yes and before doing that I still would like to see a XF/DF image from that back. As my guess is still rech camera problem.
Yes I have requested an XF+ body for demo as well. I'm still waiting for response from my dealer. Just be patient please :thumbs:
 

kdphotography

Well-known member
I still only see "one" MFDB that needs attention from the selling dealer and/or the mothership in Denmark.

While I appreciate your tenacity and persistence, I see this exercise more as a solution looking for a problem rather than the other way around. There simply are far too many open and unaddressed variables to make blanket assertions or "hasty generalizations" that Phase One will need to make a broad based IQ3 100MP effort to address the issue, if there is one at all.

Rather than depend on a rather unreliable chain of files with unknown variables, it seems pretty evident that if there is an issue, it is incumbent upon your friend to contact a dealer and/or send his MFDB back to Denmark to investigate, replicate the problem, and make the necessary repairs----rather than rely on the sporadic though well-intentioned experiences of a relatively small community of IQ3 100MP owners/users in the GetDPI family.

Ken
 
Update:

This is another demo unit I have just received today (SN: IG01112?) with firmware 4.03.2, and it is not the same demo unit I tested 6 months ago (SN: IG01109? which used to produce the red darkframe).

It's so easy to reproduce the red cast issue:

a) Power on and couple with 23mm HR with center filter without shift;
b) Set camera mode to aerial and zero latency;
c) Shoot an image at 1/60s;
d) Shoot LCC;
e) Shoot an image at 1/8s without ND filter;
f) Shoot an image at 2min with Singh-Ray 10-stop Mor-Slo (95mm thin ring);
g) Shoot an image at 30min with Singh-Ray 15-stop Mor-Slo (95mm thin ring). Bang!

Conclusion: This is not a problem with a specific unit. It could be a problem with a batch of units.

My friend almost sent his unit back to Phase One since no one at this forum admits this problem. Now he knows he's not alone and he no longer needs to send his unit back :)

I'll update with more test results later (e.g. other lenses, with XF+ body etc).

2.JPG
 
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