Rick Raines
Posts: 3
Location:
Registered: 5 Jan 2006
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Ceiling Problems
Posted: 5 Jan 2006 at 20:57 GMT
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I've been shooting for a few weeks. Sometimes, every now and then, the ceiling shot ends up with a round circle that is either lighter or darker than the rest of the area. I've tried various exposure settings but nothing is consistent in eliminating the problem. Does anyone have either an exposer or processing solution to the problem.
I use a Canon 20d with Sigma 8mm. I also use Panoweaver. Usually I "Blend" the exposure meter readings and then set it close to what is needed for the shadowed areas of the room.
Any suggestions would be greatly appreciated.
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John Houghton
Posts: 2269
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Ceiling Problems
Posted: 5 Jan 2006 at 22:37 GMT
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Are you correcting the images for light fall-off at the edges? I think the best way of doing this is during the processing of RAW images in CS2.
John
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Rick Raines
Posts: 3
Location:
Registered: 5 Jan 2006
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Re: Ceiling Problems
Posted: 7 Jan 2006 at 21:08 GMT
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Thnaks John:
No I have not. This is more than an edge problem. The entire ceiling shot will be 1-2 f stops darker or lighter in color even though nothing was changed in the shooting parameters and the shots were taken within a few seconds of the rest of the pano.
If I were to do as you suggest, how would I go about that?
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John Houghton
Posts: 2269
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Ceiling Problems
Posted: 7 Jan 2006 at 22:37 GMT
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If the ceiling shot can be either lighter or darker than the rest of the shots, then the cause cannot be simply light falloff due to the lens. That would be corrected with the vignetting option in the RAW converter. If you are shooting RAW images, then you must apply exactly the same white balance and conversion settings to all images. (You must not use any of the auto settings in the conversion). Then, if the images were taken with identical exposure settings, that should give you matching images unless there is a camera fault.
John
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Rick Raines
Posts: 3
Location:
Registered: 5 Jan 2006
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Re: Ceiling Problems
Posted: 8 Jan 2006 at 2:51 GMT
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Thanks for the idea. We haven't used RAW images. I'll try it, and let you know.
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rickdrew
Posts: 216
Location: Oak Lawn, United States
Registered: 18 Aug 2004
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Re: Ceiling Problems
Posted: 9 Jan 2006 at 8:57 GMT
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Have you tried cloning and the healing brush? I kow it's often not practical to re-shoot, and CS can usually do a nice fix-up job.
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andrew wilson
Posts: 100
Location:
Registered: 4 May 2006
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Re: Ceiling Problems
Posted: 19 Feb 2007 at 16:50 GMT
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I have encountered this problem and was wondering if anyone has any advise.
Multi-row with large windows. Each image has exactly the same exposure settings in raw. It seems that when the pano is stitched the lighter part of the celing near the windows is very apparent, almost like a large stripe. I have blended with smartblend because there is a person moving in the pano and SB seems to take care of that but because SB doesnt color correct (correct me if I am wrong) the ceiling color changes look very distinctive. Vignete control is taken care of pre stitch so that isnt the problem. I have tried cloning but didn't look good. Was wondering if there was a way of perhaps blending again in ptgui but not with smartblend.
Andrew
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Hans Nyberg
Posts: 824
Location: Denmark
Registered: 28 Aug 2005
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Re: Ceiling Problems
Posted: 19 Feb 2007 at 18:24 GMT
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You say you shoot multirow. I assume you have something like an 18-20mm on a 1.5 sensor.
That means you probably shoot at 45 degrees and 1 at 90 degrees.
If your zenith is just a large flat area with no controlpoints it is very easy that the top shot is rotated wrong.
Did you use autorotation in the camera?
This is something which can rotate the image 180 degrees.
It would explain the problem.
You should be able to see this in the editor. (PTGui)
Hans
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andrew wilson
Posts: 100
Location:
Registered: 4 May 2006
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Re: Ceiling Problems
Posted: 19 Feb 2007 at 22:57 GMT
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Thanks for the reply.
Not full spherical, 1 up 1 down at + - 30.
No autorotation, sometimes it almost looks like the exposure changed but have checked and they are all the same.
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Peter Patricelli
Posts: 114
Location: Eugene, OR, United States
Registered: 20 Dec 2006
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Re: Ceiling Problems
Posted: 20 Feb 2007 at 6:12 GMT
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Andrew,
It STILL sounds as though something is not turned off, such as auto WB?? Auto focus? Or something still on auto in the raw converter? If you are using an 8mm lens and it is not filling the full frame are you cropping out all the dark, non-image areas. If I did NOT crop when using an 8mm or 10.5mm on my full frame camera I got stitching just fine but dark bands that were blended in from the "shaded" areas around the round central image.
But I would still bet something is still active that shouldn't be. In the camera or in the raw converter. That would be virtually the only way your exposures could be off
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maxxnas
Posts: 22
Location: Bethlehem / Pennsylvania, United States
Registered: 10 May 2006
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Re: Ceiling Problems
Posted: 20 Feb 2007 at 6:20 GMT
updated: 20 Feb 2007 at 6:23 GMT
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Rick,
I ran into the exact same problems using a Canon EOS 5D and the Canon EF 15mm f.28 Fisheye lens. Although I love this combination, I noticed during many of my shoots that the ceiling was almost always 1-2 f stops lighter.
I've also heard from many other user having the same problem. A problem with camera design perhaps? Who knows. Anyway, here's how I fixed the problem.
I shoot my images in RAW mode and use the supplied Canon Digital Photo Professional Software.
1) I apply the same white balance settings to all images.
2) Then I take the ceiling shot and adjust the Brightness adjustment down 1 or 2 steps (the software uses a slider)
3) I then stitch the images in Panoweaver and they come out perfect.
This simple proceedure worked rather quickly for me. In panoweaver, you can replace any individual image in series (without reloading all the images) and continue stitching so if you need to make an additional tweek in the RAW editor, the turnover time is fast.
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Hans Nyberg
Posts: 824
Location: Denmark
Registered: 28 Aug 2005
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Re: Ceiling Problems
Posted: 20 Feb 2007 at 11:54 GMT
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maxxnas said: Rick,
I ran into the exact same problems using a Canon EOS 5D and the Canon EF 15mm f.28 Fisheye lens. Although I love this combination, I noticed during many of my shoots that the ceiling was almost always 1-2 f stops lighter.
.
I have the same setup and I never had these problems.
However I use Adobe CameraRaw for my conversions as I can do vignetting and CA in one conversion.
I have not used Canon DPP for years but I took a look at it.
I assume you are adjusting 1 image and than copy the receipe and paste it to all.
As far as I can see it is the only way to get the same conversion to all.
I also see that you use Panoweaver just like Rick.
Perhaps you should take a look at PTGui instead.
Hans
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andrew wilson
Posts: 100
Location:
Registered: 4 May 2006
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Re: Ceiling Problems
Posted: 20 Feb 2007 at 11:55 GMT
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Hello and thanks for the reply,
Peter, shots are raw so WB shouldnt matter? Maxxnas, I use capture nx for conversion and have tried your method, although it worked ok the lighter areas were still visible.
Thanks again for the suggestions
Andrew
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Hans Nyberg
Posts: 824
Location: Denmark
Registered: 28 Aug 2005
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Re: Ceiling Problems
Posted: 20 Feb 2007 at 12:46 GMT
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andrew wilson said: Peter, shots are raw so WB shouldnt matter? Maxxnas, I use capture nx for conversion and have tried your method, although it worked ok the lighter areas were still visible.
Andrew
WB matters very much if your converter is set to default. This means that it will convert the WB with the same settings as you shot it.
So if you shot with auto you get auto in the conversion.
Unless you change the WB settings in the converter to a manual.
I guess this is the same for Nicon Capture also.
I also guess that Nikon Capture has an auto setting for exposure which you have to change like you have in Adobe Photoshop CS2 Raw.
You should post a small JPG of you image for us to see and it will be much easier to diagnose.
Hans
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Peter Patricelli
Posts: 114
Location: Eugene, OR, United States
Registered: 20 Dec 2006
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Re: Ceiling Problems
Posted: 20 Feb 2007 at 18:26 GMT
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Andrew,
As Hans points out, WB matters very much even in Raw shots when you are trying to match shots. If on Auto in the camera it can change from shot to shot as the camera tries to guess what your light source it and how you might like to see it. When you open in your Raw converter (IN ACS anyway), the converter FURTHER tries to guess what the temp should be. If you turn the converter AUTO OFF, it then reverts to the camera established temp setting, which may be different than the other shots. Even if you are positive you have set the WB temp setting in the converter to the same value as the other shots, you are only hoping that the camera's idea of 5300 degrees is exactly the same as the converters ideas about 5300 degrees (temp as an example).
The test is simple, set the camera (and be sure ISO is set, not "auto iso", on MANUAL exposure mode) to a single set temp and shoot all shots. Then open in converter and be sure all AUTO's are OFF. If your ceiling shot is still 2 stops off then you HAVE A MALICIOUS GREMLIN in your camera and I suggest you get a Nikon!
Peter Patricelli
www.flyfishingfotography.com
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