Nautilus is a black-and-white photograph taken by Edward Weston in 1927 of a single nautilus shell standing on its end against a dark background. It has been called "one of the most famous photographs ever made" and "a benchmark of modernism in the history of photography."
In February, 1927, Weston visited the studio of local Carmel artist Henrietta Shore and noticed several paintings she had made of sea shells. Only one of these paintings is known to still exist (as of January, 2011), and it shows a stark and solitary nautilus on a dark field, not unlike Weston's resulting photographs. He made it clear in his writings that the paintings had a profound effect on him:
- "I was awakened to shells by the painting of Henry [Henrietta Shore]. I never saw a Chambered Nautilus before. If I had, my response would have been immediate. If I merely copy Henry's expression, my work will not live. If I am stimulated and work with real ecstasy it will live." 
Within a month he began photographing several different large chambered nautiluses, either whole or cut in half to reveal their inner structure. He used his Ansco 8 × 10 Commercial view camera with a Rapid Rectilinear lens stopped down to US256 (equivalent to f/64) . Notations he made about his exposures during this period indicate that the film he used would be rated approximately equivalent to 16 on today's ISO scale.
Due to the technical limitations of the film and the camera he used, he was forced to make extremely long exposures that were easily ruined by vibrations. Weston's grandson Kim Weston said his grandfather propped up the shell on the end of an oil drum (the arc of the drum can barely be seen in the background of the image), and the thin metal oil drum head was sensitive to the slightest movement. Weston expressed his frustrations in his 'Daybooks:
- Wednesday, June 15: "Yesterday I tried again: result, movement! The exposure was 4 1⁄2 hours, so to repeat was no joy, with all the preoccupation of keeping quiet children and cat, ‒ but I went ahead and await development."
- The next day: "The shells again moved! It must be the heavy trucks that pass jar the building ever so slightly. Anyway, I have quit trying: I can afford no more film." 
He recorded that over the next several months he made fourteen negatives of shells. It's not known exactly when he took this particular image, but it had to have been made between April 1 and June 8, 1927, when he recorded in his journal "Last evening I had printed, and am ready to show all shell negatives…".
Nautilus is now recognized as one of Weston's greatest photographs, but all of his images of shells have a greater-than-life quality to them. Weston biographer Ben Maddow has said that what is so remarkable about them "is not in the closeness nor in the monumentality of the forms; or at least, not in these alone. It is instead in the particular light, almost an inward luminescence, that he saw implicit in them before he put them before the lens. Glowing with an interior life . .. one is seeing more than form."
One historian wrote "The nautilus shells proved a turning point in Weston’s career and marked a critical phase in his development as one of the greatest photographers of the 20th century, a pioneering modernist whose stunning simplicity and technical mastery are often imitated but never quite equaled." "
Much has been said about Weston's intentions in photographing shells. He recorded that some of the first people to see them had intensely erotic reactions:
- Tina Modotti: Edward ‒ nothing in art has affected like these photographs. I cannot look at them very long without feeling exceedingly perturbed, they disturb me not only mentally but physically. There is something so pure and at the same time so perverse about them…, They are mystical and erotic."
- Diego Rivera (as described by Tina Modotti): "These photographs are biological, beside the aesthetic emotion they disturb me physically, ‒ see my forehead is sweating. Then ‒ 'Is W. very sensual?'"
- Rene d'Harnoncourt (as described by Tina Modotti): "Without my saying a word he used 'erotic' also. Like me, he expressed the disturbance these prints caused in him. He felt 'weak at the knees'."
At the same time, Weston strongly denied in his writings that he had any thought, much less intention, of recording erotic symbolism:
- "No! I had no physical thoughts, ‒ never have. I worked with clearer decision of sheer aesthetic form. I knew I was recording from within, my feeling for life as I never has before. Or better, when the negatives were actually developed, I realized what I felt, ‒ for when I worked, I was never more unconscious of what I was doing.
- No! The Shells are too much a sublimation of all of my works and life to be pigeon-holed. Others must get from them what they bring to them: evidently they do!"
Yet, in another entry about one of his nude images he said "I saw the repeated curves of thigh and calf, ‒ the shin bone, knee and thigh lines forming shapes not unlike great sea shells…"
Weston wrote that he made twenty-eights prints of this image on at least four different types of paper, including a matte Kodak Azo and a semi-gloss Agfa Convira. In a few early versions he extended the bottom margin of the image down to the notches on the film negative. Most prints measure approximately 9 1⁄2 by 7 1⁄2 in. (24 by 19 cm.)
On April 13, 2010, a print of this image made by Weston in year it was taken sold for $1,082,500 at an auction in New York. As of January, 2013, it was the fourteenth most expensive photograph ever sold. Weston originally sold it for $10.
- "Sotheby's: Edward Weston - Nautilus". Retrieved 2011-01-05.
- Aikin, Roger (Winter 1992). "Henrietta Shore and Edward Weston". American Art. 6 (1): 42–61. doi:10.1086/424140.
- Weston, Edward (1961). Nancy Newhall, ed. The Daybooks of Edward Weston, Volume II. NY: Horizon Press. p. 21.
- Newhall, Beaumont (1984). " Edward Weston's Technique", in Edward Weston Omibus. Layton, UT: Gibbs Smith. pp. 109–111. ISBN 0-87905-131-0.
- Pawlowski, Brian. "Notes on Photographing a - Nautilus". Retrieved 2011-01-05.
- Daybooks, II, p28
- Daybooks, II, 26
- Maddow, Den (1973). Edward Weston: Fifty Years. NY: Aperture. p. 69.
- Hornblow, Deborah. "Debunking the Myth of Edward Weston". Retrieved 2011-01-05.
- Daybooks, II, p31
- Daybooks, II, p32
- Daybooks, II, p10
- Conger, Amy (1992). Edward Weston: Photographs from the Center for Creative Photography. Tucson: Center for Creative Photography. pp. Fig. 544.
- Conger, Fig. 544