Results 1 to 24 of 24

Thread: Angle of light and fine image detail

  1. #1
    BPN Member Roger Clark's Avatar
    Join Date
    Feb 2008
    Location
    Colorado
    Posts
    3,956
    Threads
    257
    Thank You Posts

    Default Angle of light and fine image detail

    Attached Thumbnails Attached Thumbnails great.blue.heron.phase.study.10-30.context.jpg  

    great.blue.heron.phase.study.eye.jpg  

    great.blue.heron.phase.study.neck.jpg  

    great.blue.heron.phase.study.wing.feathers.jpg  

    After some heated discussion in the avian forum this weekend, I am posting a series of images to illustrate the the effects of phase angle on the detail in a subject.

    Phase angle: the angle between the light source (usually the sun for outdoor photography) and the camera as viewed by the subject. A simple way to determine phase angle is to stand in front of or beside you camera and straighten both arms. Make one arm parallel to the lens axis, and point the other arm toward the sun. What is the angle between your two arms? That angle is the phase angle. When your arms are pointing close to the same direction, the angle between them is small so the phase angle is low. If your arms are 90 degrees apart, and the sun is low in the sky, you have side lighting. If your arms are close to 180 degrees apart, you have back lighting.

    Many here on BPN advocate "point your shadow at the subject" but I say point your shadow close to but not quite at the subject. The closer your shadow is to the subject, the lower the phase angle and at phase angles less than about 15 degrees on birds (as well as other subjects) loses fine textural detail in the feathers, and loses color! I'll illustrate this effect with examples. The reason is when the sun is directly behind the photographer, shadows are minimized, and that includes the tiny shadows cast by fine details like grains of sand in a soil, or the structure in feathers, and from overlapping feathers, or an animal's fur. As we will see the results are quite striking!

    When in the field I have used opportunities to create a series of images at different phase angles to show phase angle effects. The series here uses a great blue heron photographed at the south end of the pond at the Venice rookery. The circular nature of the pond and a nesting GBH enabled me to move position, keeping distance pretty constant but varying the phase angle, and all in a short time (5 minutes) so sun angle stayed essentially the same. Also, the bird stayed in almost the same position for this session.

    Attached is the image showing the GBH at two phase angles: 10 and 30 degrees. The 10 degree angle had the sun behind me but overhead (I pointed my shadow at the bird). Two things to notice about this image. The 10 degree phase angle image appears flat. No shadows are there in the image to give form to the subject, Compare that to the 30 degrees phase angle image. The 30 degree phase angle image shows shading around the left side of the body giving form and adds to the dimensionality of the image. Next look at the green vegetation. The vegetation appears greener in the 30 degree phase angle image. This is because at low phase angles, first surface reflections contribute more to the observed brightness and less from light that has penetrated into the subject (e.g. the leaves). Same with the bird: the colors at 30 degrees phase are more intense (this will be more apparent in the full size image crops discussed next),

    Next look at the series showing eye detail. In all images shown here, processing was the same. At 10 degrees, there are no small shadows around the eye. But as we increase to 20, 30 and higher phase angles, shadows are cast by the tiny detail, adding form and texture to that detail. The added contrast makes the impression of a sharper image. The detail in the 10 degree phase image is only due to color variations, and not shading.

    Next look at the image series showing the feather detail in the neck. At 10 degrees, there is only a small hint of shadows and the image lacks perceived detail, even though the image is just as sharp as the other images. Moving to the 20 degree phase angle image, shadows now show between the tiny feathers, and subtle shading is showing on the left edge. Note the colors are more intense and there is a huge increase in fine textural detail.

    Now look at the final image showing wing feather detail. The 10 degree phase angle image again shows low contrast and an apparent lack of detail, and is overall flat. Yet examining the image closely shows fine low contrast detail equal in size to the detail in the higher phase images. Now examine the 20 and 30 degree phase angle images. These images show the tiny shadows case between the feathers, and within the feathers. Color and contrast are higher. Now we see that the feathers are not laying flat on top of each other as they appear in the 10 degree phase image, but the have significant 3-dimensional structure. Moving to 60 degrees phase angle adds more structural detail.

    Of course as one moves to higher phase angles, large scale 3-dimensional structure can make deep shadows. This is apparent with the bird's body at 60 degrees and is beginning to become apparent in the 30 degree phase image above. So there is a peak in optimum phase angle: avoid low phase angles, usually below 15 degrees so that you have some shading. If the light is directional, avoid higher phase angles (depends on how contrasty the shadows are), but above about 45 to 60 degrees shadows can become too deep.

    The optimum phase angle is often in the 20 to 30 degree range, where there is enough shading to give form, fine texture, and better color than at lower or higher phase angles. What this means is don't point your shadow towards the subject if the sun is low in the sky. However, as Art Morris has said, if the sun is high in the sky, then pointing one's shadow toward the subject minimizes harsh shadows and is the way to go. But in that case the phase angle is higher anyway so you are already working above the low phase angle region.

    Keep above 15 or so degrees phase angle to add form, texture, and better color to your images.

    Roger

  2. Thanks Neil Jeffrey, kim wormald thanked for this post
  3. #2
    Avian Moderator arash_hazeghi's Avatar
    Join Date
    Oct 2008
    Location
    San Francisco, California, United States
    Posts
    11,788
    Threads
    751
    Thank You Posts

    Default

    Attached Thumbnails Attached Thumbnails crop-BBP.jpg  

    AH__9512.jpg  

    IMG_5500.jpg  

    I am not sure about this test, it seems the critical focus was on the head and as the head was rotated towards the viewer in the first frame the body was outside DOF, it looks OOF to me. Looks like the GBH was moving both his head and body in between the shots which makes "angle" measurements dubious. I don't see any difference in the head crops were the critical focus was so overall I am not sure if this proves anything...The crops are also heavily compressed and over-sharpened which makes it difficult to compare.



    Here is my idea of a sharp crop. I don't measure angles but I put the sun behind me.

    Attachment 103256

    Attachment 103257

    Attachment 103258
    New! Canon EOS AF Guide for avian in flight photography
    ------------------------------------------------
    Visit my avian galleries
    http://www.ari1982.smugmug.com

  4. #3
    BPN Member Roger Clark's Avatar
    Join Date
    Feb 2008
    Location
    Colorado
    Posts
    3,956
    Threads
    257
    Thank You Posts

    Default

    Quote Originally Posted by arash_hazeghi View Post
    I am not sure about this test, it seems the critical focus was on the head and as the head was rotated towards the viewer in the first frame the body was outside DOF, it looks OOF to me. Looks like the GBH was moving both his head and body in between the shots which makes "angle" measurements dubious. I don't see any difference in the head crops were the critical focus was so overall I am not sure if this proves anything...The crops are also heavily compressed and over-sharpened which makes it difficult to compare.

    Here is my idea of a sharp crop. I don't measure angles but I put the sun behind me.
    Arash,

    A simple look at the catchlight in the eye of the 10 degree phase image and you will see 1) it is tiny, 2) round, and 3) much smaller than the catchlights in the images you posted. The image was done at 1/1600 second at 500 mm, f/5.6, ISO 400 on a tripod. Look at the second image you posted: the catchlight is oblong from the upper left to lower right indicating camera or subject movement during exposure, thus not critically sharp. My images are more than sharp enough to illustrate the effects.

    Your low phase angle images show just the results I have been discussing: lack of fine textural detail due to lack of tiny shadows.

    This phase angle effect is not just something I invented. It is a well known and well documented effect known for many decades. See for example, Hapke, B.,1993, Introduction to the Theory of reflectance and Emittance Spectroscopy, Cambridge University Press, New York (and many references therein). A little research on your part (as someone attending grad school should be familiar with) would easily verify these effects.

    Roger



  5. #4
    Avian Moderator arash_hazeghi's Avatar
    Join Date
    Oct 2008
    Location
    San Francisco, California, United States
    Posts
    11,788
    Threads
    751
    Thank You Posts

    Default

    Quote Originally Posted by Roger Clark View Post
    Arash,

    A simple look at the catchlight in the eye of the 10 degree phase image and you will see 1) it is tiny, 2) round, and 3) much smaller than the catchlights in the images you posted. The image was done at 1/1600 second at 500 mm, f/5.6, ISO 400 on a tripod. Look at the second image you posted: the catchlight is oblong from the upper left to lower right indicating camera or subject movement during exposure, thus not critically sharp. My images are more than sharp enough to illustrate the effects.

    Your low phase angle images show just the results I have been discussing: lack of fine textural detail due to lack of tiny shadows.

    This phase angle effect is not just something I invented. It is a well known and well documented effect known for many decades. See for example, Hapke, B.,1993, Introduction to the Theory of reflectance and Emittance Spectroscopy, Cambridge University Press, New York (and many references therein). A little research on your part (as someone attending grad school should be familiar with) would easily verify these effects.

    Roger


    Roger,

    I think your test is invalid, the heron has obviously moved and parts of the bird was outside the focus plain, not to mention the poor IQ crops-they don't prove anything IMHO. It blows my mind that you consider this a "controlled" test and extract an angle from these images.

    I also think you have trouble seeing/identifying sharpness. I find it astonishing that you think there was motion blur in the crops I posted...just beyond me

    Anyways the images speak for themselves, let people see and decide what is critically sharp and what is not.

    Also I am not attending school, and I find your reference quite irrelevant to photography, you seem to confuse phases of moon, astronomy, spectroscopy and other things with avian photography-I hope you can figure out, best of luck :)
    New! Canon EOS AF Guide for avian in flight photography
    ------------------------------------------------
    Visit my avian galleries
    http://www.ari1982.smugmug.com

  6. #5
    Forum Participant
    Join Date
    Mar 2010
    Location
    San Jose, CA
    Posts
    116
    Threads
    3
    Thank You Posts

    Default

    Those crops look great Arash! VERY sharp...motion blur you gotta be kidding me

    Roger I think you sharpened your crops way too much that's why the edges show so much halo and grains. Maybe you shot in JPEG mode? Perhaps do the test with something that doesn't move so you don't have to worry about focus, looks like the distance to the heron changed as well, closer in the right one? As Arash pointed angle measurements are not very reliable.

    I am not sure about the conclusion either, to me the left image is better than the right image, the right image has harsh shadows in the plumage.

    Just my 2 cents.

  7. #6
    Forum Participant
    Join Date
    Jan 2011
    Posts
    364
    Threads
    18
    Thank You Posts

    Default

    I think notwithstanding what people think about image sharpness I can see the effect of shading on rendering of feather definition. It is interesting to see the impact of phase angle on rendering. Even in cartoon images, the addition of shadows does add dimension and impact, I think this is good exercise in image perception and the degree to which direction of light impacts our perception of the image.

  8. #7
    BPN Member Humberto Ramos's Avatar
    Join Date
    Apr 2010
    Location
    Portalegre, Portugal
    Posts
    547
    Threads
    59
    Thank You Posts

    Default

    I don't know if the test valid or invalid, if the images are in focus or out of focus, but one think I do know, a small amount of shadows in my photos are always welcome. Once with a cloudy day, decided to mounted 3 flashes for fotographing little birds, one in front of the camera, and the other two 45º each side. The images where very sharp (subject distance was 4m), but at the same time, they where completely flat and without "live". After this I tried one single flash at 30 to 45ª and the images where amazing...
    Humberto Ramos

    www.humbertophoto.com


    "If your pictures aren't good enough, you're not close enough" - Robert Capa

  9. #8
    Lifetime Member Jay Gould's Avatar
    Join Date
    Mar 2009
    Location
    In the whole wide world!
    Posts
    2,732
    Threads
    313
    Thank You Posts

    Default

    I am trying to understand what everyone is arguing about?

    There is no question, now that I as a nonscientific lay person, is going to get serious, that if the light is directly on the subject with absolute no angle then there by definition cannot be any shadow whatsoever; the direct light is illuminating the cracks, crevasses, feather edges, etc.

    Arash, do you disagree with that statement?

    John Shaw, one of the most famous landscape photographers, writes in his Nature Photography Field Guide:

    Light is what makes photography possible. In fact, the very word "photography" means "painting with light." Notice that the subject of the photograph is not mentioned in this definition; photography is the process of capturing light on film, not of capturing a subject on film. ...

    Light has a direction, a character, and a color. The ability to recognize these distinctions and the ways in which they can be used graphically, both singly and in combination, is one of the things that sets the professional photographer apart from the amateur. ...

    As the name implies, frontlighting is light falling on the side of the subject facing the camera. The sun is directly behind the photographer, coming right over his or her shoulder. It is the old standard lighting situation that many of us learned to misuse with our first box camera. How many family pictures have you seen of a row of people squinting into the sun shining directly in their faces? Direct frontlighting wipes out any shadows. It is probably the worst lighting possible for landscape photographs, because it makes the scene appear flat and one dimensional. On the other hand, it is the perfect lighting for most tight bird and mammal portraits, because all parts of the
    subject are illuminated equally. It's extremely disconcerting to see an animal photo where one side of the creature is totally lost in deep black shadows; we want to see the entire animal, not just part of it. ...

    Sidelighting emphasizes the shape and texture of a subject, since it creates shadows. In turn, the shadows caused by sidelighting add to the three-dimensional feeling of a photograph. For these reasons, landscape photography is often done in the sidelight of early morning and late afternoon. ...
    I would suggest that all Roger is saying, applying these obvious principles, is you have to give a little to get a lot. With a 0% phase angle you will get a a subject where "all parts of the subject are illuminated equally" and it will also be "flat and one dimensional"

    Give a little, have the sun behind you but not exactly directly behind you, some angle away from behind you, a phase angle greater than 0%, and you will get some change in the lighting that "emphasizes the shape and texture" of the bird "since it creates shadows"; and "in turn, the shadows caused by ... [a phase angle greater than 0% and perhaps closer to 30%, i.e.,] side lightiing add[s] to the three-dimensional feeling of a photograph."


    And, so that we do not limit this post to landscape photographers, Moose Peterson in his book "Captured " writes in describing a photo of a Musk Ox:

    What makes that photograph work is the play of the white against the brown and all the small shades in between that are naturally found in their fur. Introduce direct light to that and you start losing those subtle shades and the minute detail in the browns.
    Makes sense to me!
    Cheers, Jay

    My Digital Art - "Nature Interpreted" - can now be view at http://www.luvntravlnphotography.com

    "Nature Interpreted" - Photography begins with your mind and eyes, and ends with an image representing your vision and your reality of the captured scene; photography exceeds the camera sensor's limitations. Capturing and Processing landscapes and seascapes allows me to express my vision and reality of Nature.

  10. #9
    Random Pixel Generator Michael Lloyd's Avatar
    Join Date
    Jan 2008
    Location
    Weimar, TX
    Posts
    934
    Threads
    274
    Thank You Posts

    Default

    I am trying to understand what everyone is arguing about?
    "Everyone" isn't... Seems like this happens all the time and it's getting kind of old.

    I'm glad that you put the quotes from John Shaw and Moose Peterson up Jay. They seem to know a little about photography...

  11. #10
    BPN Member Dennis Bishop's Avatar
    Join Date
    Mar 2008
    Location
    southeast Michigan
    Posts
    1,665
    Threads
    108
    Thank You Posts

    Default

    Roger, I think you make a great point and you documented it very well. Thanks for all the detail. (Pun intended.)
    “ . . . The executional characteristics of the image should not be the first thing you notice when you look at the photograph: you can overdo it. They should support the compositions, but not detract or outweigh it. This is one of the things I don’t like about overdone HDR, Instagram and other photo apps – the processing is so overdone to the point that fundamental compositional structure is overshadowed, and any flaws hidden. You only see the processing, and not the subject.” -- Ming Thien, in What makes an outstanding image? (part 1) on his blog, http://blog.mingthein.com, October 6, 2012

  12. #11
    BPN Member Roger Clark's Avatar
    Join Date
    Feb 2008
    Location
    Colorado
    Posts
    3,956
    Threads
    257
    Thank You Posts

    Default

    Attached Thumbnails Attached Thumbnails clark-arash-compare.jpg  

    Quote Originally Posted by Dan Avelon View Post
    Those crops look great Arash! VERY sharp...motion blur you gotta be kidding me
    Here is a comparison of of the catchlights in the eyes of the images being discussed. Regarding sharpness, my images show much smaller and rounder catchlights. The Arash #2 image, in particular shows an oblong catchlight (other reflections on the bill also show similar blur), thus it appears there was camera movement during exposure. Arash 3 is shows the best catchlight of Arash's posted images, but the catchlight is still larger than that in my GBH image. The catchlight proves my image is sharply focused and that there was no motion blur or subject movement.

    I did sharpen my GBH images more than I normally would because I was trying to bring out at least some fine detail in the 10 degree phase image. But remember, all images I posted had the same sharpening applied. So regardless of any sharpening artifacts, my images can be compared relative to each other to show the effects of phase angle. This charade of attacking sharpness is irrelevant to the large effects shown as a function of phase angle.

    Low phase angle images can have several perceptual and one practical effects: 1) flat appearing subject, 2) lack of fine textural detail, 3) with #2 a perceived lack of sharpness even with a perfectly focused and sharp image, 4) lower contrast, and the practical side effect: the lower contrast can mean more errors in the AF accuracy.

    Roger

  13. #12
    BPN Member mikeojohnson's Avatar
    Join Date
    Jan 2008
    Location
    Estero, Florida
    Posts
    97
    Threads
    13
    Thank You Posts

    Default

    Remember what Chas always says: "Light illuminates, shadows define"....

    Mike

  14. #13
    Avian Moderator arash_hazeghi's Avatar
    Join Date
    Oct 2008
    Location
    San Francisco, California, United States
    Posts
    11,788
    Threads
    751
    Thank You Posts

    Default

    The size of the catchlight depends on the particular bird's pupil characteristics. GBHs and egrets catchlights are smaller than shorebird catchlights, terns have even larger catchlights. The heron's head was way smaller in the frame, even the heavily enlarged pupil doesn't show a well defined catchlight.

    I think It is naive to equate a larger catch light with motion blur-as the sharp fine details tell a different story-experienced photographers know this very well. I am not sure if a single competent photographer who has spent time looking at RAW files will agree there was motion blur in these crops and that just tells about one's experience in seeing and perceiving sharpness IMHO.


    @ Jay, off axis light does create local shadows, and it does change perception of the image, Does it make it better or worse? IMO there is no single answer or a single angle that produces the best results all the time. Depth perception is subjective. I personally don't like shadows as they make the plumage appear harsh but my style of photography is different. I have no problem with creative use of shadows though.
    At the end of the day, you have to create a pleasing photograph, and that's all that matters IMO. How you arrive at that is your own personal choice. you can use side light, back light, front light....as long as your photo is on the money you're good whether the light was at 0 degrees or 10 degrees or 10.12456 degrees. If you get down to measuring angles but produce a poor photograph at the end of the day it is a failure.

    Good luck with your photography and expeditions.
    New! Canon EOS AF Guide for avian in flight photography
    ------------------------------------------------
    Visit my avian galleries
    http://www.ari1982.smugmug.com

  15. #14
    Forum Participant Bob Decker's Avatar
    Join Date
    Nov 2009
    Location
    North Carolina's Crystal Coast
    Posts
    382
    Threads
    84
    Thank You Posts

    Default

    It's portrait photography 101: frontal light results in flat, images. As the light moves more to one side of the other, up to 90 degrees, more modeling and texture will be present in the image. When I first attended a workshop on off-camera flash for location portraits we did a similar series of image. Leaving the model and light in one positon we move about in a semi-circle taking shots at different positions to see how light direction affects the resulting image. It's also still-life photography 101: Try the same exercise using an orange. Light it from camera position then work the light or camera around the subject to create a variety of lighing positions around the orange. Watch how texture and color is affected.

    Roger's examples seem fine to me. I suspect Arash is simply looking for an arguement. For what reason I don't know. I do agree with Arash, however, that it's up to the photographer's personal tastes. It's not so much a matter of one style of light being better than another, but understanding of how lighing conditions effect images so one can make good choices. Frontal lighting, side lighting, back lighting... hard light, soft light... it all effects the final image and how one approaches making an image.

  16. #15
    Random Pixel Generator Michael Lloyd's Avatar
    Join Date
    Jan 2008
    Location
    Weimar, TX
    Posts
    934
    Threads
    274
    Thank You Posts

    Default

    @Bob- well said

    @Roger- maybe it would sell better if you used another term? Phase angle may be too complex a term lol


    ---
    I am here: http://maps.google.com/maps?ll=28.880380,-95.572314

  17. #16
    Avian Moderator arash_hazeghi's Avatar
    Join Date
    Oct 2008
    Location
    San Francisco, California, United States
    Posts
    11,788
    Threads
    751
    Thank You Posts

    Default

    Quote Originally Posted by Bob Decker View Post
    It's portrait photography 101: frontal light results in flat, images. As the light moves more to one side of the other, up to 90 degrees, more modeling and texture will be present in the image. When I first attended a workshop on off-camera flash for location portraits we did a similar series of image. Leaving the model and light in one positon we move about in a semi-circle taking shots at different positions to see how light direction affects the resulting image. It's also still-life photography 101: Try the same exercise using an orange. Light it from camera position then work the light or camera around the subject to create a variety of lighing positions around the orange. Watch how texture and color is affected.

    Roger's examples seem fine to me. I suspect Arash is simply looking for an arguement. .
    Bob, thanks for your comments. We were not talking about studio portrait or still life photography here. Things sure become quite tangled quickly. It was claimed above that you need a certain angle 10 degrees, -5 degrees, 16.023 degrees whatever to make an appealing and detailed avian image in all conditions. I disagree, very simple. I said that there is no one angle and it depends on various field parameters. If you disagree and would prefer using a ruler to shoot at a certain angle all the time that’s fine, go for it-I am not arguing.

    My goal was not to initiate an argument. My goal was to share my perspective in making avian images.

    Thank you very much for your comments and good luck.
    New! Canon EOS AF Guide for avian in flight photography
    ------------------------------------------------
    Visit my avian galleries
    http://www.ari1982.smugmug.com

  18. #17
    Forum Participant Todd Frost's Avatar
    Join Date
    Jan 2008
    Location
    Washington
    Posts
    2,080
    Threads
    225
    Thank You Posts

    Default

    Arash, while you have some fantastic images one can always take away something from anothers perspective. I'm not sure anyone has stated that the only way to achieve a good image is with a 10 degree or whatever angle but that it opens up other posibilities.

    Todd

  19. #18
    Forum Participant Bob Decker's Avatar
    Join Date
    Nov 2009
    Location
    North Carolina's Crystal Coast
    Posts
    382
    Threads
    84
    Thank You Posts

    Default

    We were not talking about studio portrait or still life photography here.
    Physics is physics. Doesn't matter what kind of photogrpahy you're talking about the effect of lighting angles on subjects applies.

    It was claimed above that you need a certain angle 10 degrees, -5 degrees, 16.023 degrees whatever to make an appealing and detailed avian image in all conditions.
    but perhaps you should read things twice before making a judgment.
    You might want to take your own advice. If you didn't notice I said that: "I do agree with Arash, however, that it's up to the photographer's personal tastes. It's not so much a matter of one style of light being better than another, but understanding of how lighing conditions effect images so one can make good choices."

  20. #19
    BPN Member Roger Clark's Avatar
    Join Date
    Feb 2008
    Location
    Colorado
    Posts
    3,956
    Threads
    257
    Thank You Posts

    Default

    Quote Originally Posted by arash_hazeghi View Post
    The size of the catchlight depends on the particular bird's pupil characteristics. GBHs and egrets catchlights are smaller than shorebird catchlights, terns have even larger catchlights. The heron's head was way smaller in the frame, even the heavily enlarged pupil doesn't show a well defined catchlight.
    Arash,
    The optics of catchlight in an eye is the same as that for an "artificial star" that is used in optical testing. The equations are published, e.g. see Star Testing Astronomical Telescopes by H. R. Suiter, 1994, Willmann-Bell, Richmond, Appendix F.

    With the sun as the source for the catchlight, the reflection spot diameter is approximately the eye diameter / 300. For a bird with a 2 cm diameter eye, the spot is ~ 20000/300 = ~66 microns. A 1 cm diameter eye would produce a spot about 33 microns diameter. It is simple geometry to work out the apparent size: it will be at the camera. At a distance of 10 meters, even a 2 cm diameter eye will produce a 1.4 arc-second diameter catchlight. Some more simple geometry shows that a 500 mm lens on a 1D IV has pixels subtending 2.3 arc-seconds, so even a large eye is sub-pixel; i.e. effectively a pinpoint star. It then matters not if the eye and catchlight is even smaller.

    Stars by the way are the very tough tests of an optical system. The fact that the catchlight in my image is small and round attests to the high image quality. The fact that the catchlight in your #2 image is not round is a definite reduction in image quality, in this case due to either subject or camera movement.

    Quote Originally Posted by arash_hazeghi View Post
    It was claimed above that you need a certain angle 10 degrees, -5 degrees, 16.023 degrees whatever to make an appealing and detailed avian image in all conditions. I disagree, very simple. I said that there is no one angle and it depends on various field parameters. If you disagree and would prefer using a ruler to shoot at a certain angle all the time that’s fine, go for it-I am not arguing.
    Arash, please go back and read again. No one said certain angles were needed "to make an appealing and detailed avian image in all conditions."

    For example, I summarized my post "Keep above 15 or so degrees phase angle to add form, texture, and better color to your images." This is a fact that not only many photographers say and write about, but is also based in science. That does not mean one must only do a certain thing, nor that appealing images can't be made at low phase angles. Your RTH image is certainly appealing (I also said it was sharp). That does not mean people can't have opinions on improving it. But you objected when such opinions were given.

    Quote Originally Posted by arash_hazeghi View Post
    My goal was not to initiate an argument.
    You may certainly choose to make all your images at low phase angles, but if someone comments in a critique forum giving a critique about your image, it is their opinion. One can certainly disagree, but you must respect other people's opinion.

  21. #20
    Forum Participant
    Join Date
    Mar 2010
    Location
    San Jose, CA
    Posts
    116
    Threads
    3
    Thank You Posts

    Default

    Quote Originally Posted by Roger Clark View Post
    Here is a comparison of of the catchlights in the eyes of the images being discussed. Regarding sharpness, my images show much smaller and rounder catchlights. The Arash #2 image, in particular shows an oblong catchlight (other reflections on the bill also show similar blur), thus it appears there was camera movement during exposure. Arash 3 is shows the best catchlight of Arash's posted images, but the catchlight is still larger than that in my GBH image. The catchlight proves my image is sharply focused and that there was no motion blur or subject movement.

    I did sharpen my GBH images more than I normally would because I was trying to bring out at least some fine detail in the 10 degree phase image. But remember, all images I posted had the same sharpening applied. So regardless of any sharpening artifacts, my images can be compared relative to each other to show the effects of phase angle. This charade of attacking sharpness is irrelevant to the large effects shown as a function of phase angle.

    Low phase angle images can have several perceptual and one practical effects: 1) flat appearing subject, 2) lack of fine textural detail, 3) with #2 a perceived lack of sharpness even with a perfectly focused and sharp image, 4) lower contrast, and the practical side effect: the lower contrast can mean more errors in the AF accuracy.

    Roger
    Roger I don't want to take sides here I appreciate your efforts but I don't think there is motion blur in any of those crops. I have photographed some of these birds myself and these crops are as sharp as it gets IMO, I am sure there are many great shorebird shooters here who will chime in as well. I think sometimes you don't agree with the obvious facts.

    Thank you for discussion I do see the point about shadows creating depth and volume but the details are still great in Arash's crops too. So I think we should all be receptive to alternative opinions and not close our minds with a single approach. At the end of the day we all want to get the best image.


    Dan

  22. #21
    Lifetime Member Jay Gould's Avatar
    Join Date
    Mar 2009
    Location
    In the whole wide world!
    Posts
    2,732
    Threads
    313
    Thank You Posts

    Default

    the catchlight is oblong from the upper left to lower right indicating camera or subject movement during exposure, thus not critically sharp. My images are more than sharp enough to illustrate the effects.

    Did I miss something? I am not taking sides; I am trying to be objective about what the (?) "friendly combatants" have said.

    Roger did not say that Arash's images were not sharp; he did say that scientifically - I am not a scientist - because the catchlight is oblong and not round, the fact of being oblong means that there was movement at the moment of capture.

    This is not a discussion of whether Arash's images are sharp! Bloody **** as we say Down Under; Arash's images are as sharp as any EVER posted on BPN.

    This was/is a discussion about how the angle of the sun falling on the subject creates or eliminates shadows and depth depending upon the angle.

    Unfortunately, it also became a discussion about catchlights - NOT IMAGES - and how you might discern if there was movement - any movement - at the time of capture.

    Arash, to my understanding, only HHs his cameras.

    Was the bird moving at the time of capture; was the camera moving at the time of capture; was the shutter speed insufficient to eliminate this small change in the catchlight while being fast enough to create what everyone would consider a sharp image?

    These are appropriate questions.

    Personality comments; ability comments; knowledge comments that become personalized are inappropriate comments.
    Cheers, Jay

    My Digital Art - "Nature Interpreted" - can now be view at http://www.luvntravlnphotography.com

    "Nature Interpreted" - Photography begins with your mind and eyes, and ends with an image representing your vision and your reality of the captured scene; photography exceeds the camera sensor's limitations. Capturing and Processing landscapes and seascapes allows me to express my vision and reality of Nature.

  23. #22
    Forum Participant
    Join Date
    Mar 2010
    Location
    San Jose, CA
    Posts
    116
    Threads
    3
    Thank You Posts

    Default

    Quote Originally Posted by Jay Gould View Post
    Did I miss something? I am not taking sides; I am trying to be objective about what the (?) "friendly combatants" have said.

    Roger did not say that Arash's images were not sharp; he did say that scientifically - I am not a scientist - because the catchlight is oblong and not round, the fact of being oblong means that there was movement at the moment of capture.

    This is not a discussion of whether Arash's images are sharp! Bloody **** as we say Down Under; Arash's images are as sharp as any EVER posted on BPN.

    This was/is a discussion about how the angle of the sun falling on the subject creates or eliminates shadows and depth depending upon the angle.

    Unfortunately, it also became a discussion about catchlights - NOT IMAGES - and how you might discern if there was movement - any movement - at the time of capture.

    Arash, to my understanding, only HHs his cameras.

    Was the bird moving at the time of capture; was the camera moving at the time of capture; was the shutter speed insufficient to eliminate this small change in the catchlight while being fast enough to create what everyone would consider a sharp image?

    These are appropriate questions.

    Personality comments; ability comments; knowledge comments that become personalized are inappropriate comments.
    I have some files myself where the catch light is not round but the photo is plenty sharp. sometimes there are multiple reflections from the pupil itself that are rendered as a few hot pixels that are very close to each other and look like a big catchlight. sometimes if the sun is too low the catchlight from the sun and sun's reflection in the water merge and create a tall catchlight. Based on the feather details I can't see how there was motion blur, if something had moved the feathers would be blurry too, not the case here.

  24. #23
    Super Moderator Daniel Cadieux's Avatar
    Join Date
    Jan 2008
    Location
    Ottawa, Canada
    Posts
    16,574
    Threads
    1,974
    Thank You Posts

    Default

    Hey all, healthy debate is good and encouraged, but please keep it civil and polite. We can all learn from this thread, but lets make it a pleasant learning experience

  25. #24
    BPN Member
    Join Date
    Sep 2012
    Location
    London
    Posts
    211
    Threads
    39
    Thank You Posts

    Default

    Thanks Roger.

    I have to agree with you as I have noticed this many many times with my pictures.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Web Analytics