burake
Posts: 282
Location: Antalya, Turkey
Registered: 7 Jun 2012
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nadir (blending?) problem
Posted: 5 Dec 2012 at 11:52 GMT
updated: 5 Dec 2012 at 11:56 GMT
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Hi everyone,
Learning to make panoramic images looks to be a long, very long path  ...In a recent shooting I have a darker area on the ground which first I couldn't understand what exactly is...I thought first it must be the shadow of the tripod but on my nadir image there's no such shadow...I made similar shootings in several rooms with the same "light coloured floor" and had in all similar problems...Then I realized it is the place where my tripod is standing while taking my shots around - after that I move the tripod by side and use the "nadir adapter" for the nadir shot which is a great great help...Equipment; 5dmark2, Canon 8-15 mm at 12 mm (4x around +1 nadir), Manfrotto 055xprob and NN5...I shoot RAW and then use 8-bit tiff images for stitching...I tried also with 16-bit tiff; the darker area doesn't cahnge...Here's a sample with the .swf output file and the images (in jpeg in order to keep the .zip file small)...
ge.tt/1UUhExS?c
(my question is about the large darker coloured area and not the hole which can be avoided by shooting when the tripod is placed properly)
Any idea how to solve this problem?
Any help will be greatly appreciated
Burak
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hindenhaag
Posts: 844
Location: Netherlands
Registered: 7 Mar 2010
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Re: nadir (blending?) problem
Posted: 5 Dec 2012 at 14:03 GMT
updated: 5 Dec 2012 at 14:28 GMT
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Burak,
I stitched your pics only with Nadir 1 shot:
ge.tt/1PVxjxS/v/0
All these pics are taken at the same time and have metadata, AWB.
No shadow on the left side where I used Nadir1. The picture Baülçksçz-1.jpg has no metadata and when I remember well, it was shot earlier on another day? Plus it seems to be an already stitched image.
You should set everything to manual. So the images should have same focus, aperture, shutter speed and white balance and should be taken at the same time.
May be that's why. You should try to stand outside the picture taking your nadir shots 
Have a look at this as well @zoom set to 12mm: www.lenstip.com/311.8-Lens_review-Canon_EF_8-15_m...
So long,
Heinz
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hindenhaag
Posts: 844
Location: Netherlands
Registered: 7 Mar 2010
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Re: nadir (blending?) problem
Posted: 5 Dec 2012 at 14:41 GMT
updated: 5 Dec 2012 at 14:44 GMT
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BTW:
you can download a lens profile for your camera lens combination with adobe lens profile downloader. But just a jpeg version.
But check the info of the profile. Seems to be shot at one focus distance only.
Heinz
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John Houghton
Posts: 3710
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: nadir (blending?) problem
Posted: 5 Dec 2012 at 16:22 GMT
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Burak, The nadir adapter doesn't solve all problems when shooting the nadir. You need to take sufficient shots to capture the whole nadir area without intrusive shadows, using as many shots as necessary. In this example, there are areas where the blender has no choice but to use darker areas in shadow to give the (almost) complete nadir area.
John
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burake
Posts: 282
Location: Antalya, Turkey
Registered: 7 Jun 2012
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Re: nadir (blending?) problem
Posted: 6 Dec 2012 at 12:52 GMT
updated: 6 Dec 2012 at 12:54 GMT
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Heinz thank you very much for your help and the link...I forgot to say that in the zip file there are not only the images of the shooting but also one .jpg file which I have extracted from the flash file in order to show the "darker area" better...That picture is a result of stitching...Everything was on manual and the same settings for all images except for the WB. I shot in AWB and changed temperature and tint later on in the RAW files to have the same values in every shot...The link you've provided about the 8-15 mm lens was very interesting...
John thank you very much for your reply...The shadows must be the problem...I did indoor shooting with this combination before but didn't have this problem...When I go throu those examples I see that the ground was dark coloured or in one example where the ground was light coloured the shooting was made only in daylight...I remember "the quality" of light is important, artificial light sources with low Kelvin values and coming from direct sources cause harsher shadows and that could probably be the issue here...
Best regards
Burak
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DennisS
Posts: 1622
Location: Los Anglels, United States
Registered: 1 Sep 2007
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Re: nadir (blending?) problem
Posted: 6 Dec 2012 at 14:46 GMT
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burake,
In PTGui, if you turn on the seams, you will see how different the brightness is between the pictures. Sometimes I adjust the brightness of individual images prior to stitching. Let's call it "fine tuning".
Shadows can be a real pain to deal with. Go outside on a sunny day with the sun low in the sky and shoot a pano. You will quickly see that more than 1 single Nadir patch shot is required in order to capture enough "shadow free" images. Most times I take 1 final hand held Nadir patch shot offset from the center of camera rotation just so I can have an image without the camera shadow in the way.
It is the same for indoor panoramas. Sometimes you need to take more than 1 Nadir patch shot using one of several techniques available in order to have enough shadow free pictures. In a "4 around" shoot you may have 6 or more pictures to deal with in the final stitch.
Dennis
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hindenhaag
Posts: 844
Location: Netherlands
Registered: 7 Mar 2010
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Re: nadir (blending?) problem
Posted: 6 Dec 2012 at 16:26 GMT
updated: 6 Dec 2012 at 16:38 GMT
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Burake ,
Dealing with nadir problems in PTGui, you can play around with "Blend Priority".
You can change this from 100% >40% for example to get a good stitch without stitching errors, but only for your nadirs shots.
ge.tt/5n4Se2T/v/0
By changing this value, imagine a circle, the info to PTGui will be reduced more and more to the center of the image.
Just play around with your pics by changing blend priority to learn about this problem.
Keep cool, everyone of us is facing new problems every day.
It is a steady workflow of trying to learn to solve new problems.
The basic info for all these new questions and golden key for your work is basic knowledge about camera lens combination:
Test shots at 5.6, 8, 11 aperture settings testing different focal distance to find out the best focal setting for your combination. Hyperfocal distance set up.
Next step is to find out "Turning Point of Noise" for each aperture and ISO.
Consequence: set of pics for every aperture setting raising ISO to check the last ISO setting before getting Noise.
Raising ISO will result in shorter shutter speeds. Taking pics for panos in busy places or using bracketing shots you should try to avoid ghosts of moving people, clouds or waves at the sea etc by raising ISO.
In case you face a busy place, just raise ISO to get shorter shutter speeds.
But Noise will ruin your set.
To cut it short: You only will get the best out of your pics specially for panos, having tested the basics of you camera lens combinations.
This will enable everyone of us to adapt settings to the special shooting place.
The very experienced friends like John are very close to final point of the "journey". Be sure, you have to follow "the walk through a desert".
Conclusion: Do a lot of tests. Once you are convinced about your camera lens combinations settings, go out to shoot.
Burake, I adore the way you improve your work.
Just a personal comment for newbies:
Taking good basic quality Panos is'nt a "Plug and Play" job.
A lot of information to do a good job is required. So this will take time.
So long,
Heinz
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burake
Posts: 282
Location: Antalya, Turkey
Registered: 7 Jun 2012
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Re: nadir (blending?) problem
Posted: 8 Dec 2012 at 19:22 GMT
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Thank you very much for the useful tips guys..
Best regards
Burak
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