Code Editor for app.py

import streamlit as st

st.title("Sunny 16 Rule Calculator")
st.write("""
The Sunny 16 Rule is a method to estimate correct exposure for photography without using a light meter. 
The basic rule states: On a sunny day, set aperture to f/16 and shutter speed to the reciprocal of the ISO speed.
""")

# Input for ISO
iso = st.selectbox("Select ISO", [100, 200, 400, 800, 1600, 3200, 6400])

# Input for lighting conditions
lighting_conditions = st.selectbox(
    "Select Lighting Conditions",
    [
        "Sunny (f/16)",
        "Slightly Overcast (f/11)",
        "Overcast (f/8)",
        "Heavy Overcast (f/5.6)",
        "Sunset (f/4)",
        "Deep Shade/Dusk (f/2.8)"
    ]
)

# Get the f-number from the selected lighting condition
f_number = float(lighting_conditions.split("(f/")[1].strip(")"))

# Calculate the base shutter speed (reciprocal of ISO)
base_shutter = 1/iso

st.subheader("Calculated Exposure Settings:")
st.write(f"📷 Aperture: f/{f_number}")
st.write(f"⚡ Base Shutter Speed: 1/{int(1/base_shutter)} second")

# Show equivalent exposures
st.subheader("Equivalent Exposures:")
st.write("Here are some equivalent exposures that will give you the same exposure value:")

exposures = []
current_f = f_number
current_shutter = base_shutter

# Generate 3 wider apertures and 3 narrower apertures
for i in range(-3, 4):
    new_f = current_f * (2 ** (i/2))
    new_shutter = current_shutter * (2 ** i)
    if new_f >= 1.4 and new_shutter <= 1:  # Only show realistic values
        exposures.append({
            "Aperture": f"f/{new_f:.1f}",
            "Shutter Speed": f"1/{int(1/new_shutter) if new_shutter < 1 else new_shutter} sec"
        })

st.table(exposures)

st.info("""
Remember:
- Opening up the aperture by one stop (smaller f-number) requires doubling the shutter speed
- Closing down the aperture by one stop (larger f-number) requires halving the shutter speed
""")