Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: ZOG on February 20, 2008, 07:47:59 pm
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Hello everyone. I just did some test for a nightime shot I will have to do my new P45+ on Mamiya 645 AFDII.
I'm getting strange artifacts at 100% mag. of a night shot. I don't think this is normal. I have seen much cleaner files from you guys.
Picture taken at 100ASA. 3 sec. F:8
Color temp corrected in C1 at 2450K with a +20M color correction.
No other corrections were applied. (normal exposure)
Unsharp setting: Amount 80 Threshold 3
Noise suppression at low
Banding suppression at off.
I really don't like the "painterly" effect I'm getting.
The image is cropped at 100% and saved as a jpeg 10.
Oh yes by the way: C1 3.7.8 DB
Thanks!
Andre[attachment=5206:attachment][attachment=5207:attachment]
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I'm wondering about the purple color of the middle floors of the office building. Or is it just my monitor?
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I really don't like the "painterly" effect I'm getting.
[a href=\"index.php?act=findpost&pid=176300\"][{POST_SNAPBACK}][/a]
Can you be more specific about the artifacts you're seeing? I'm not seeing much in the first photo because it's so dark.
The 2nd photo has some strange looking "flare" across the building to be sure. My night time long exposures have been of different subjects, but none have given me this look, either.
-Brad
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The 2nd shot looks like some type of sensor blooming. Likewise, I can't figure out what I'm suppose to look for in the first crop.
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Is it Quebec city?
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The second shot appears to have a blue hotspot which I typically get in some situations with some optics. The hotspot is only seen on dark things.
I have experienced this with, Zeiss ZF 50/2.0macro,HC35/3.5 & Nikkor 85PC sofar but I doubt these are the only ones that show this. I have samples of this phenomena with dark clothing, shoes & other accessories as well as indoor shots of stuff like showrooms. It happens on certain distances, especially close distance.
In my case most of this occurred with shots on white backgrounds. I opened a case with Zeiss, they acknowledged the problem eventually and told me it was due to the optically design of the that specific lens.
I opened a case for the Nikkor 85PC as well, I tried various samples and all of them exhibited the same kind of optical phenomena.
You might experience the same type of thing. Try shooting a dark object on white also on f8 and see if you get the same thing.
Color of the hotspots seemed to vary with either lenscoating or IR filter color of the back in use, not sure about that.
This is the reply I got from Zeiss on my questions about this:
"we did several tests to evaluate the problem. The Makro Planar T* 2/50 ZF seems to be susceptible for the occurence of such a bluish reflection at close distances under such lighting conditions because of its optical design. The blue spot is only visible on dark subjects - on white subjects the difference in hue and saturation is too small to get visible.
The only way to avoid this problem is to take image with less of the bright white background or to use another lens. The Macro Planar T* 2/100 ZF does not produce any blue spot under the same lighting conditions. "
I got similar replies from Nikon but that was longer ago so I can't find these that quickly (and they are probably in Dutch anyway).
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Please forget about the colors on the large building. It's special lighting. It's the texture I'm concerned about. BTW, yes David, it's Quebec city....
Thanks!
Andre
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Difficult to judge from an image downsized this far. Could you post 100% crops of areas that are of specific concern?
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A few things...
A> Which lens did you use for this shot, it appears the lens may not have the resolving power you need.
B> Same shot at ISO 50 will give you better quality (has to do with the algorithms)
C> Be sure to do this type of shot with the file type IIQ RAW L .... you mention "new" be sure your software is NOT set to "Raw - compatible with 3.0" that is a incorrect default setting in 3.77 & 3.78
D> What color space are you shooting it in? Which are you processing to?
E> When processing... are you processing it out to a 8 bit TIF then converting later to JPEG or are you processing straight to JPEG?
F> If you wish, I would be glad to take a look at your RAW file, contact me direct for FTP instructions.
Tim
Tim Palmer
Tech Support
Capture Integration
tim@captureintegration.com
404-522-7662
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You are right, a P45 file should not have 'painterly' effect at a relatively short exposure time of 3 sec. You should be able to take it to 20 secs plus. At 3 sec you should have a super clean file.
I think you should do the another test to confirm these results. Preferably with two different lenses. Make sure the mirror is locked up. I think you have two separate issues: Flare and 'Painterly'
I had similar flare on a H3D39 that was green with multiple lenses. I was told the flare was caused by the IR filter and has been solved in the H3Dii. My point is that by testing multiple lenses (different focal lengths) that you can determine if it's the back or the lens for the flare.
The painterly effect maybe the settings in the software. Maybe someone else could chime in on C1. I'm more of the king of finding flare in all the wrong places :-)
Peace,
Weldon
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Thanks everyone. I'll be going back tonight. I'll keep you posted.
(It will be -21˚C.......)
Andre
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Please forget about the colors on the large building. It's special lighting. It's the texture I'm concerned about. BTW, yes David, it's Quebec city....
Thanks!
Andre
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I asked if it was Quebec city because I thought it could have been a special lighting on the building...
It was on purpose. 400th anniversary of the City.
d
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I do a lot of really long exposures with the p45+. http://www.p45plus.typepad.com (http://www.p45plus.typepad.com)
It looks out of focus.
My Tips -
You need a sharp lens, 120 macro
Use mirror up
Use cable release.
You may be doing all three of these, but I just wanted to make sure.
JP
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HI,
I shoot a lot of night, long exposure work and that texture in the image looks very much like the artifacts left behind when noise removal has been applied to a noisy image.
When I was shooting DSLR, I used noise ninja to 'clean up' the images. If the combination of smoothness, strength of the filter and contrast (noise ninja's main controls) were applied in a certain way to a noisy image, that 'painterly effect' you describe as exactly what resulted.
Cheers
Murray
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HI,
I shoot a lot of night, long exposure work and that texture in the image looks very much like the artifacts left behind when noise removal has been applied to a noisy image.
When I was shooting DSLR, I used noise ninja to 'clean up' the images. If the combination of smoothness, strength of the filter and contrast (noise ninja's main controls) were applied in a certain way to a noisy image, that 'painterly effect' you describe as exactly what resulted.
Cheers
Murray
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I don't believe that this is the issue here. What you are talking about, I have notice and d70 and d2x files - the painterly effect, but never see it on p45+ files. They basically look as sharp as day. Even up to 20 minute exposure.
Regards,
JP
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It looks over exposed to me, given the dynamic range in the scene.
John