• petrochemistpanorama_fish_eye
    208 posts
    a year ago

    With many fisheye lenses the distortion will NOT look normal viewed close up (I'm not sure any do) There are multiple fisheye designs which map the view in different ways (the mapping function section of en.wikipedia.org/wiki/Fisheye_lens shows this well), some of my 'fisheye' converters cram a significant part of their FOV into the very edges of the image. I think the 'Equisolid angle' function is the nearest for these. Fortunately most of my true fisheye lenses are closer to equidistant or stereographic designs & give a much better image. However fisheye lenses are a rather special case, using distortion to fit in more than would normally be possible!

    Changes to the viewing conditions are not the perspective of the print, they relate to a viewing perspective that is not part of the print. There are certainly conditions where the viewing perspective can correct for distortion of perspective in an image. For rectilinear lenses Ansel's claim that perspective of a print is dependant only on camera-subject distance is 100% correct. Not a fallacy as the OP claimed.

  • TomAxfordpanorama_fish_eye
    562 posts
    a year ago

    At last we are getting somewhere!

    You seem now to admit that when the viewer's position changes, the perspective seen by the viewer changes.

    Of course, the print itself doesn't change when it is viewed from a different position. The perspective seen by the viewer is a combination of the perspective captured in the image (which depends on the camera position) and the perspective distortions introduced by the viewer's position (relative to the centre of perspective of the image).

    The passage by Ansel Adams that I quoted in the OP talks about "wide-angle perspective" and "telephoto perspective". He says that they are caused by the camera-to-subject distance, which is wrong. That is where the fallacy is.

  • petrochemistpanorama_fish_eye
    208 posts
    a year ago

    I never denied that and neither did Ansel. perspective that is down to unusual viewing conditions is not perspective of the image.
    The perspective of the image is totally down to distance from subject.

    IIRC Ansel covered changes in apparent perspective due to viewing conditions in his later book in the series on printing. Viewing conditions of the print being quite irrelevant to 'The Camera' where the passage quoted orginally came from.

  • TomAxfordpanorama_fish_eye
    562 posts
    a year ago

    I agree with that, except that viewing conditions do not always need to be "unusual" to cause perspective distortions.

    If you make images and never view them, what is the purpose of the image?

    As soon as you view your images, the viewing conditions need to be taken into account because they can change the perspective that the viewer sees (of course, they do not change the perspective captured in the image).

  • petrochemistpanorama_fish_eye
    208 posts
    a year ago

    Ansel's book series The Camera, The Negative & The Print, cover different parts of the photographic process i.e. shooting, developing & printing. Between them they cover the whole process. The quote in the original post is from the Camera, so would not be expected to go into print viewing.

    If you buy a book on morning coffee, do you expect it to talk about late night teas ?

  • sybersitizenpanorama_fish_eye
    167 posts
    a year ago

    TomAxford is now going through the same thing with you that he went through with me earlier in the thread.

    IMO, the real fallacy here is the fallacy of readers expecting all the facts about perspective to appear in one book without reading the others.

  • a year ago

    Yes: this and similar active threads without entertaining photos, which are in the majority at present here, are getting very boring! 😀

    David

  • bobn2panorama_fish_eye
    a year ago

    Depends what floats particular peoples' boats. We've got room for it all here.

  • a year ago

    But the rest is not happening. There is a serious imbalance of topics.

    David

  • TomAxfordpanorama_fish_eye
    562 posts
    a year ago

    In that case, the topics of wide-angle perspective and telephoto perspective should not have been mentioned. They both depend on the print viewing conditions. Ansel Adams should not have said that "The flatness of space is again caused by camera position (distance) rather than focal length" because it is simply untrue. It is actually caused by the print being viewed from much closer than the centre of perspective.

    It would have been much better if he had simply said "read my third volume 'The Print' for the correct explanation".

    I do not have a copy of 'The Print' and I wonder whether it does give an explanation of perspective distortions such as wide-angle perspective and telephoto perspective. If anyone has access to a copy, can you quote the appropriate paragraphs?

  • NCVpanorama_fish_eye
    2023 posts
    a year ago

    I have the Adams trilogy. In the "Print" he makes no mention of viewing perspective. His only mention of perspective seems to be in the "Camera".

    The "Print" is mostly about the technical issues of printmaking.

  • sybersitizenpanorama_fish_eye
    167 posts
    a year ago

    That's incorrect. Twice in this thread I've posted an image of a page in The Print, and now for the third time:

    The Print - Viewing Perspective.jpg

    I posted it to prove that there is no 'Ansel Adams Fallacy'.

    This is the source: archive.org/details/The_Print/page/n83/mode/2up

  • TomAxfordpanorama_fish_eye
    562 posts
    a year ago

    That discussion is very superficial. He makes no mention of "wide-angle perspective" or "telephoto perspective" and there is no attempt to explain them.

  • sybersitizenpanorama_fish_eye
    167 posts
    a year ago

    Yes, your own 'perspective' on this has been established, and I do not agree with it.

  • TomAxfordpanorama_fish_eye
    562 posts
    a year ago

    So, you do not agree with my statement in bold above. Please quote the paragraphs in which Ansel Adams explains "wide-angle perspective" and "telephoto perspective."

  • sybersitizenpanorama_fish_eye
    167 posts
    a year ago

    I do not agree that his trilogy was intended or expected to address perspective as anything more than the few sentences he chose to write. He knew the principles, but unlike some people, he was clearly not obsessed with that particular subject. I already expressed these things earlier in the thread and am not going to continue playing tug-of-war with you. Go back and read them if you need to. I re-posted the pages from the book to correct NCV's comment, and that's all.

  • TheDavinatorpanorama_fish_eye
    621 posts
    a year ago

    Did JACS leave? Every post of his is deleted.

  • bobn2panorama_fish_eye
    a year ago

    It seems he's deleted them all.

  • TomAxfordpanorama_fish_eye
    562 posts
    a year ago

    Maybe he saw the light?

  • ArvoJlens
    a year ago

    Or found different perspective?

  • JACShelp_outline
    878 posts
    a year ago

    I am here but I decided to stop posting at least for now. My oldest posts are still here, but my most recent ones are deleted, indeed.

    Why - those forums turned into some form of generic "social media" which I dislike. I do not have FB, Instagram, X, etc., accounts. At dpreview in the old times, at least, the off topic discussions were clearly separated from the rest and did not bother me. Not here.