Questions tagged “f number”

Ask the Unique Photo creator community — gear, technique, post-processing and more.

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128

Why can’t a variable-aperture zoom like 18-140mm open wider at the short end?

nikon lenses aperture f-number zoom-lens

Saurav Majumder

1y ago

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114

Why are standard f-number values like f/5.6 and f/22 not mathematically rounded consistently?

aperture f-number standards photography-basics exposure

Photography Stack Exchange contributor

3y ago

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133

How do I choose an f-number when designing a camera system?

lens-design aperture f-number camera-design optics

Photography Stack Exchange contributor

3y ago

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262

How does f-number affect exposure, and why does the simple rule break down at close focus?

macro aperture f-number optics exposure

Photography Stack Exchange contributor

4y ago

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166

Does a front-mounted teleconverter change the f-number of a lens?

lenses aperture f-number optics teleconverter

Photography Stack Exchange contributor

5y ago

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118

Why doesn’t a zoom lens’s physical aperture opening get larger as focal length increases?

lens-design aperture f-number zoom-lens manual-lenses

Photography Stack Exchange contributor

5y ago

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149

Does a larger sensor collect more total light at the same field of view and f-number?

depth-of-field field-of-view f-number sensor-size exposure

Photography Stack Exchange contributor

5y ago

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185

What is Aperture Value in EXIF, and how does it relate to the f-number?

metadata aperture f-number exif exposure

Photography Stack Exchange contributor

6y ago

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221

Why are apertures labeled with f-numbers instead of stop values like Av 0, 1, 2... ?

depth-of-field aperture f-number optics exposure

Photography Stack Exchange contributor

6y ago

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218

Why does a smaller f-number mean more light, even if the aperture diameter stays the same?

lenses aperture f-number optics exposure

Photography Stack Exchange contributor

7y ago

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114

Why can a 400mm f/4 lens have a smaller-looking aperture than 100mm?

lenses aperture f-number optics entrance-pupil

Photography Stack Exchange contributor

7y ago

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113

Why doesn’t a larger lens diameter change exposure if the focal length and f-number stay the same?

lenses aperture f-number optics exposure

Photography Stack Exchange contributor

7y ago

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197

How do you calculate light loss in stops from a teleconverter’s magnification?

math aperture f-number teleconverter exposure

Photography Stack Exchange contributor

8y ago

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105

Can a full-frame lens be made effectively faster on a smaller sensor by shrinking its image circle?

focal-reducer lenses crop-sensor f-number exposure

Photography Stack Exchange contributor

9y ago

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149

What is the smallest aperture (highest f-number) found on production lenses?

lenses diffraction aperture f-number medium-format

Photography Stack Exchange contributor

9y ago

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144

What does 1:4–5.6 mean on a lens?

lens aperture f-number basics zoom-lens

Photography Stack Exchange contributor

9y ago

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344

How do the f-number formulas f/D and 1/(2NA) relate, and why does NA suggest a limit near f/0.5?

lens-theory aperture f-number optics numerical-aperture

Photography Stack Exchange contributor

10y ago

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137

Why does the same f-number give the same exposure at different focal lengths?

aperture f-number optics focal-length exposure

Photography Stack Exchange contributor

10y ago

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151

Is an f-stop lower than f/1 physically possible?

lenses aperture low-light f-number optics

Photography Stack Exchange contributor

10y ago

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118

Why do larger sensors often have better low-light performance if f-number already accounts for light gathering?

lenses aperture low-light f-number sensor-size

Photography Stack Exchange contributor

10y ago

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