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IQ4 Live View Overexpose

eisbaer

Member
Hi,

since the Feature Update 8, I have the problem that the Live view of my IQ4 is much to bright. I am in simulation mode, look at the RAW Histogramm and it looks good (ETTR wise) then I take the picture, but this is 1-2 stops darker. I searched here but found nothing(IQ4 Live View overexpose, underexpose etc). Hope that this thread is not redundant...
If you want to see a sample, I took a small video here to show it.

Or am I doing something wrong. My main problem is that I can't use the RAW Histogramm any more, as it is useless if Live View and taken picture Differ so much.

Frank
 

Greg Haag

Well-known member
Frank, hopefully someone can help with this, I have a similar but opposite problem, my live view is much too dark and my histogram is not accurate. Maybe it is as simple as I have something set wrong?


Shot of live view
5958415C-C8F4-4B10-98E9-212547716FB7_1_105_c.jpg


Actual shot
A7365DB4-E7FE-4AEC-BD20-664F45717B8C_1_105_c.jpg
 

eisbaer

Member
Strange... I reverted to the 7.x Firmware and everything is fine there... I had hoped that others have the same problem, but if you have it the other way round its really strange...
 

vieri

Well-known member
Hey Frank,

sorry to hear about the problem - it seems to me from the video you posted that the RAW histogram and the JPG histogram look totally different, but your RAW histogram looks like it's indeed somewhere around two stops underexposed, which matches what you see in terms of the resulting picture. Have you tried to have the RAW histogram looking perfectly exposed, forgetting the JPG histogram, and see what that does? Just a suggestion of course :)

Best regards,

Vieri
 

eisbaer

Member
Hi Vieri,

thanks for the input. Maybe I said it wrong. I am looking at the RAW Histogramm, but the 1st priority for me is the highlight Clipping. As the RAW Histogramm is difficult to read if you have only small parts in the image which are overexposed. When I take a picture with the 8.x Firmware the clipping shows much to early. I can perfectly recover everything even if the clipping tells me I am way to bright. I reverted, again to Firmware 7.x and there it matches. Not perfectly but quite good. I look at the live view, take the picture and the difference which are there, are because of the applied in camera profile (Contrast, Saturation etc.) But brightness stays the same and I can work.

I wonder as it seems that not many others have the problem. Greg seems to have it other way round, which is not better either.. but all others. No change between live View simulation and taken picture?
 

Paul2660

Well-known member
Live View, exposure simulation for me on the IQ4 has always been an issue of under exposure, not sure if it's 2 stops or 1.5, but I have quit using the "auto" mode which I assume is the exposure simulation, since the image displayed on the back's LCD is always under exposed and tends to be hard to determine accurate manual focus.

But I have noticed that this entire feature has always been much less workable than what was available on the 3100. I don't remember the 3100 have the exposure simulation mode, but the manual slider was much more accurate. What I tend to see with the IQ4 with manual slider is a constantly changing amount of display illumination, where the LCD tends to flash too bright, then too dark a few times, before settling down to where it feels it should be. I use Live View 100 percent for focus, on either tech camera or XF.

I use the slider to push the image on the screen to see the details enough to get focus, then manually attempt to dial it in. Usually takes about 2 attempts.

Note this is with a tech camera, and I have always assumed the auto mode is dysfunctional since the back has no idea what the actual aperture is (same reason the EXIR feature won't work on non XT tech cameras, (but should on the XF)).

I really need to try the XF again and see if auto exposure is any better.

I guess it doesn't bother me that much is I am usually at base ISO or 100 and most often am shooting with dual exposure which has so much shadow relief. I tend to try to allow for a bit of under exposure knowing I can get it back in post easily. But it would be nice to hear from others if they feel the auto exposure mode is working correctly with either a non XT camera (XF or non XT tech camera).

I almost always use the ES on tech camera, never the copal. So for live View I will have the aperture on the shutter manually set to where I plan to shoot. I am not sure how this feature work or is supposed to work not the XF, which should be opening up the aperture all the way to max for focusing, then stopping down to selected aperture during exposure.

Paul C
 

vjbelle

Well-known member
I also have had issues with live view being too bright with the resulting file being about 1.3 stops underexposed. The top RGB histogram while in live view will quickly reach to the edge of the overexposed side while the RAW histogram shows a much less exposed image. It also depends on the scene. I would certainly rather have a slightly underexposed image than overexposed. But it would be helpful if this could be more accurate - like any off the shelf mirrorless camera is.

Victor B
 

Bill Caulfeild-Browne

Well-known member
After reading this thread I decided to take a hard look at my Live View. Using Manual exposure, I adjust the ISO/Aperture/Shutter so the pointer is at the centre of the scale. This results in an excellent RGB histogram but a Raw histogram pushed way over to the left. The actual shot is right on, and when I chimp, the histogram in the preview matches the histogram I saw in LV..
This is true for both the XF and XT. In summary, LV (Sim) looks good and exposes properly. Also, using AV or TV gives the same result The only issue is the Raw histogram which I ignore. If I used it to set exposure everything is blown right out. Needs some work. I'm not sure this is very helpful but it's my 2C worth.

I also played with ETTR which I have already found very useful in snow scenes. It's fun to watch it change the exposure you've set. Unfortunately ETTR it doesn't show up in the EXIF though the changed ex[osure does. However, given that I really like Dual Exposure+, I probably won't use ETTR much except where there's significant movement.
 
Since feature update 8 I also noticed my IQ4’s live view feed to be overexposed in Simulated Exposure Mode compared to the actual exposure settings when I have the IQ4 attached to my reprographic camera on a copy stand for film digitization. For example, when my correct ETTR shutter speed is 1/13 at ISO 50 I get RAW clipping warning in the blue channel. Only at 1/40 or faster shutter speeds the RAW clipping warning disappears. So the live view feed is at least 1.5 stops brighter than the actual exposure settings. As I rely on live view for fine focus tuning, I have currently set it to Auto-Exposure or View Finder Mode which works for me as my light is controlled. However, the auto-exposure flicker when the back switches back and forth between exposure settings is annoying. And yes, Simulated Exposure was working fine for me on the previous firmware. I cannot recall having noticed any recent issues with live view when I had the IQ4 attached to my XF. So the issue could be limited to when the IQ4 is not attached to any Phase One camera.

I will create a support case on this and can only encourage everyone who is experiencing the same issue to do so as well to let Phase One know that this is not a single user problem.

-Dominique
 

alistairsimmons

Well-known member
I haven't noticed anything particular to Firmware 8, but I always put the (in my experience slight, but noticeable) exposure difference in live view vs captured preview down to the fact that the live preview has no curve on it, where the captured preview has an Auto Curve as per Capture One.
 

eisbaer

Member
Hi Dominique,

so it seems you experience the exact behavior as I have, I already open a support Ticket with P1. I will link to the thread and note your Post. Thanks for your comment.

Frank
 

vjbelle

Well-known member
What I find confusing is that there are times when reliance of the RGB histogram is all that is needed. I push that exposure to the right and I get a fairly good exposure with a histogram that comes close to the live view.

Other times with the same scene but more contrasty the RGB histogram will give me an underexposed image but if I rely on the RAW histogram I get a good exposure with histograms from live view and the taken image close to each other. The RAW histogram also very closely matches the exposure meter for correct exposure but the RGB histogram is now pushed way to the right. Maybe it just takes experience......

It would be helpful if Phase One provided documentation explaining how the histograms work but I couldn't find any. What does the RGB histogram measure? What does the RAW histogram measure. What is the exposure meter pegged to?

Victor B
 

bab

Active member
Rawviewer can help, not sure if the raw histogram is per channel that would be lovely.
 
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