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#21
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Photographing birds in flight
M-M wrote:
In article , "Roger N. Clark (change username to rnclark)" wrote: There should be no exif data as the jpegs are stripped to reduce size. You remove the EXIF purposely to reduce the size, or reducing the size removes the EXIF? For web images I use photoshop's save for web function. It strips out all the extraneous header info to reduce the byte count of the image. Smaller image size in bytes = faster download times. I have started turning on the ICC profile so ICC data are included in my newer images. That increases file size by only a few tens of bytes. Roger |
#22
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Photographing birds in flight
Dr. Joel M. Hoffman wrote:
Beautiful gallery! According to the EXIF data, these are scans. Yes? Thanks. No, they are all digital, mostly 1D Mark II. There should be no exif data as the jpegs are stripped to reduce size. There's lots of EXIF data, with fields such as "Progressive Scans," "Device Attributes," etc. I don't know much about the EXIF fields; I thought those looked like scanner attributes. BTW, as a reminder: http://exif.posted-online.com will display a web page and add EXIF-data boxes for all the images. -Joel Interesting. I exified this image: http://www.clarkvision.com/galleries...8715b-700.html The info beyond basic image data appears to be entirely due to the embedded sRGB ICC profile and the jpeg compression. The is no exif data about the image and its creation. The "Device Attributes," etc. are ICC profile data. Roger ExifTool Version Number : 6.70 File Type : JPEG MIME Type : image/jpeg JFIF Version : 1.2 Resolution Unit : None X Resolution : 100 Y Resolution : 100 Quality : 70% Profile CMM Type : Lino Profile Version : 2.1.0 Profile Class : Display Device Profile Color Space Data : RGB Profile Connection Space : XYZ Profile Date Time : 1998:02:09 06:49:00 Profile File Signature : acsp Primary Platform : Microsoft Corporation CMM Flags : Not Embedded, Independent Device Manufacturer : IEC Device Model : sRGB Device Attributes : Reflective, Glossy, Positive, Color Rendering Intent : Media-Relative Colorimetric Connection Space Illuminant : 0.9642 1 0.82491 Profile Creator : HP Profile ID : 0 Profile Copyright : Copyright (c) 1998 Hewlett-Packard Company Profile Description : sRGB IEC61966-2.1 Media White Point : 0.95045 1 1.08905 Media Black Point : 0 0 0 Red Matrix Column : 0.43607 0.22249 0.01392 Green Matrix Column : 0.38515 0.71687 0.09708 Blue Matrix Column : 0.14307 0.06061 0.7141 Device Mfg Desc : IEC http://www.iec.ch Device Model Desc : IEC 61966-2.1 Default RGB colour space - sRGB Viewing Cond Desc : Reference Viewing Condition in IEC61966-2.1 Viewing Cond Illuminant : 19.6445 20.3718 16.8089 Viewing Cond Surround : 3.92889 4.07439 3.36179 Viewing Cond Illuminant Type : D50 Luminance : 76.03647 80 87.12462 Measurement Observer : CIE 1931 Measurement Backing : 0 0 0 Measurement Geometry : Unknown (0) Measurement Flare : 0.999 % Measurement Illuminant : D65 Technology : Cathode Ray Tube Display Red Tone Reproduction Curve : (Binary data 2060 bytes, use -b option to extract) Green Tone Reproduction Curve : (Binary data 2060 bytes, use -b option to extract) Blue Tone Reproduction Curve : (Binary data 2060 bytes, use -b option to extract) DCT Encode Version : 100 APP14 Flags 0 : [14], Encoded with Blend=1 downsampling APP14 Flags 1 : (none) Color Transform : YCbCr Image Width : 700 Image Height : 560 Image Size : 700x560 |
#23
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Photographing birds in flight
Dr. Joel M. Hoffman wrote:
2b. I know the 30D can follow soaring birds and keep focus. (Take a look at: Sorry to follow up on my own post. In response to people who have asked, I've posted some close-ups on: http://www.posted-online.com/ArizonaBirds/Page1.html and http://www.posted-online.com/ArizonaBirds/Page2.html and moved the other pages, so the owl- and hawk-series pages are now: http://www.posted-online.com/ArizonaBirds/Page3.html and http://www.posted-online.com/ArizonaBirds/Page4.html BTW, for a good reason NOT to use JPEG, take a look at the bottom picture on http://www.posted-online.com/ArizonaBirds/Page1.html ( http://posted-online.com/ArizonaBirds/pix/14.jpg - 100K ). Notice the blue hues around the green leaves. There was no blue in the original picture. Sigh. Nice shots but I don't know why a jpeg would produce those blues... that doesn't sound right? |
#24
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Photographing birds in flight
Dr. Joel M. Hoffman wrote:
( http://posted-online.com/ArizonaBirds/pix/14.jpg - 100K ). Notice the blue hues around the green leaves. There was no blue in the original picture. Sigh. I've noticed when slightly over-exposing darks on hard white that there are similar artificats. Not sure why "blue" comes out. -- -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. |
#25
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Photographing birds in flight
On Sat, 07 Apr 2007 18:23:11 GMT, Paul Furman wrote:
( http://posted-online.com/ArizonaBirds/pix/14.jpg - 100K ). Notice the blue hues around the green leaves. There was no blue in the original picture. Sigh. Nice shots but I don't know why a jpeg would produce those blues... that doesn't sound right? I don't think it's a jpeg produced artifact. You often get color fringing when objects have an intensely bright background, such as the sky, and better lenses produce less of it. The blue in this shot is probably so easily noticed because it covers a greater area due to being considerably out of focus. I've noticed CA having several different colors, sometimes blue, sometimes purple, yellow or orange. The glossary entry (link below) mentions that CA often increases when a lens is used at its widest, and that the commonly noticed "purple fringing" is probably more due to the sensor's microlenses than a result of the lens's design. http://www.dpreview.com/learn/?/Glos...rration_01.htm |
#26
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Photographing birds in flight
Ed Ruf (REPLY to E-MAIL IN SIG!) wrote:
On Sat, 07 Apr 2007 18:23:11 GMT, in rec.photo.digital Paul Furman wrote: Dr. Joel M. Hoffman wrote: ( http://posted-online.com/ArizonaBirds/pix/14.jpg - 100K ). Notice the blue hues around the green leaves. There was no blue in the original picture. Sigh. Nice shots but I don't know why a jpeg would produce those blues... that doesn't sound right? I've seen something similar , even in raw files from a D70 processed by RSE. Probably a bit of bloomimg/CA? I'll conject it's the blue sky, un-overexposed by diminution of intensity by the palm-frond filter. Similar effect: Overexposed out of the direct sun, greater color saturation under the shade of the pier. http://www.fototime.com/8D5F43553123D59/orig.jpg -- Frank ess |
#27
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Photographing birds in flight
"Ed Ruf (REPLY to E-MAIL IN SIG!)" wrote in message ... : On Sat, 07 Apr 2007 18:23:11 GMT, in rec.photo.digital Paul Furman : wrote: : : Dr. Joel M. Hoffman wrote: : : ( http://posted-online.com/ArizonaBirds/pix/14.jpg - 100K ). Notice : the blue hues around the green leaves. There was no blue in the : original picture. Sigh. : : Nice shots but I don't know why a jpeg would produce those blues... that : doesn't sound right? : : I've seen something similar , even in raw files from a D70 processed by : RSE. Probably a bit of bloomimg/CA? : -- : Ed Ruf ) : http://edwardgruf.com/Digital_Photog...ral/index.html I can get that effect with 5D if I use a cheap, long lens wide open and the foliage is backlit.I always thought it was Chromatic Aberration. Just out of focus like the rest of the area. |
#28
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Photographing birds in flight
: ( http://posted-online.com/ArizonaBirds/pix/14.jpg - 100K ). Notice
: the blue hues around the green leaves. There was no blue in the : original picture. Sigh. I can get that effect with 5D if I use a cheap, long lens wide open and the foliage is backlit.I always thought it was Chromatic Aberration. Just out of focus like the rest of the area. Hmm. It's with the Canon 17-85 IS USM (f/8, 1/640, ISO 500), not a great lens, but not a cheap one, either. A long time ago someone posted a digital way of eliminating or reducing CA, but I've lost the link. My guess is that whatever digital magic does this won't work with out-of-focus CA, but I'd be curious to find out. If someone has access to this anti-CA filter, feel free to play around with the image and post what you learn.... -Joel ---------------------------------------------------------------------------- EXIF data for any image or web page: http://exif.posted-online.com ---------------------------------------------------------------------------- |
#29
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Photographing birds in flight
"Dr. Joel M. Hoffman" wrote in message ... :: ( http://posted-online.com/ArizonaBirds/pix/14.jpg - 100K ). Notice : : the blue hues around the green leaves. There was no blue in the : : original picture. Sigh. : : I can get that effect with 5D if I use a cheap, long lens wide open and the : foliage is backlit.I always thought it was Chromatic Aberration. Just out of : focus like the rest of the area. : : Hmm. It's with the Canon 17-85 IS USM (f/8, 1/640, ISO 500), not a : great lens, but not a cheap one, either. : : A long time ago someone posted a digital way of eliminating or : reducing CA, but I've lost the link. My guess is that whatever : digital magic does this won't work with out-of-focus CA, but I'd be : curious to find out. If someone has access to this anti-CA filter, : feel free to play around with the image and post what you learn.... : : -Joel : : ---------------------------------------------------------------------------- : EXIF data for any image or web page: http://exif.posted-online.com : ---------------------------------------------------------------------------- : Look for "Flo's tools" This Frenchman has produced a really nice set of very useful tools which are camera make independent, they just need a PS compatible program to use as a host. |
#30
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Photographing birds in flight
Dr. Joel M. Hoffman wrote:
You remove the EXIF purposely to reduce the size, or reducing the size removes the EXIF? I just went through this dilemma. When I created a web page for my birds from Arizona, I decided to keep the EXIF data in the thumbnails. This increased the size of each thumbnaim from about 7K to about 22K. That's a really big difference, especially for people using dial-up connections. Yes, I don't keep it in thumbnails. But for the actual image, say 700 pixels on the long side and probably 50k-100k in size, I leave EXIF and IPTC data in. I want the location and date and any people identified to stay with the photos if they're saved and passed around. Of course that's dependent on the type of photography I do; for many other subjects it doesn't seem that useful (beyond the date and geographic location anyway). |
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