diff --git a/crates/pipeline/src/tests_geometry.rs b/crates/pipeline/src/tests_geometry.rs
index 3be2dc1806..12f9ca88ad 100644
--- a/crates/pipeline/src/tests_geometry.rs
+++ b/crates/pipeline/src/tests_geometry.rs
@@ -597,3 +597,19 @@ fn auto_straighten_takes_the_roll_from_converging_verticals() {
     let deg = auto_level(&line_drawing(&lines)).expect("the vanishing point");
     assert!((deg + 3.0).abs() < 0.3, "{deg}");
 }
+
+/// The cached analysis tells lenses apart: the analysis image is corrected for `info.lens`, and
+/// Auto straighten reads the horizon from a fresh image and the lines from the cache, so a hit
+/// for another lens would mix two frames (review of #2809).
+#[test]
+fn the_analysis_cache_tells_lenses_apart() {
+    let src = tilted_scene(2.0, 30.0);
+    let s = DevelopSettings::default();
+    let plain = SourceInfo::default();
+    let vignette = lightcraft_develop::EmbeddedVignette::default();
+    let lens =
+        SourceInfo { lens: Some(lightcraft_develop::EmbeddedLens { vignette: Some(vignette), ..Default::default() }), ..SourceInfo::default() };
+    let key = crate::upright::analysis_key;
+    assert_eq!(key(&src, &plain, &s), key(&src, &plain.clone(), &s), "the same source, settings and lens");
+    assert_ne!(key(&src, &plain, &s), key(&src, &lens, &s), "another lens");
+}
diff --git a/crates/pipeline/src/upright.rs b/crates/pipeline/src/upright.rs
index f90bd2c4ad..e9ce00695b 100644
--- a/crates/pipeline/src/upright.rs
+++ b/crates/pipeline/src/upright.rs
@@ -553,8 +553,7 @@ pub fn analyze_source(src: &Rgb32f, info: &SourceInfo, s: &DevelopSettings) -> A
 /// cache miss instead of building it again.
 fn analyze_cached(src: &Rgb32f, info: &SourceInfo, s: &DevelopSettings, plane: Option<&Plane>) -> Analysis {
     static CACHE: Mutex<Vec<(u64, Analysis)>> = Mutex::new(Vec::new());
-    let key = crate::optics::fingerprint(src)
-        ^ lightcraft_develop::DevelopSettings { optics: s.optics, orientation: s.orientation, ..Default::default() }.hash64().rotate_left(17);
+    let key = analysis_key(src, info, s);
     if let Ok(c) = CACHE.lock()
         && let Some((_, a)) = c.iter().find(|(k, _)| *k == key)
     {
@@ -573,6 +572,17 @@ fn analyze_cached(src: &Rgb32f, info: &SourceInfo, s: &DevelopSettings, plane: O
     a
 }
 
+/// What an analysis depends on: the source's pixels, the optics and orientation settings, and the
+/// lens the frame is corrected for (`info.lens`, which [`analysis_plane`] reads through the frame).
+pub(crate) fn analysis_key(src: &Rgb32f, info: &SourceInfo, s: &DevelopSettings) -> u64 {
+    use std::hash::{Hash, Hasher};
+    let mut lens = std::collections::hash_map::DefaultHasher::new();
+    format!("{:?}", info.lens).hash(&mut lens);
+    crate::optics::fingerprint(src)
+        ^ lightcraft_develop::DevelopSettings { optics: s.optics, orientation: s.orientation, ..Default::default() }.hash64().rotate_left(17)
+        ^ lens.finish().rotate_left(29)
+}
+
 /// The image an analysis reads: the lens-corrected source (optics applied, no perspective or crop)
 /// at [`ANALYSIS_LONG`] px, as perceptual lightness normalized to its bright end.
 pub(crate) fn analysis_plane(src: &Rgb32f, info: &SourceInfo, s: &DevelopSettings) -> Plane {