Why do snowflakes look larger at a wider aperture?
Asked 2/27/2018
3 views
2 answers
0
When photographing falling snow, I noticed that images shot at a wider aperture seem to show bigger or more noticeable snowflakes than images shot at a smaller aperture with a longer shutter speed. For example, using the same ISO and focal length, a shot at f/3.2 and 0.5s showed more prominent flakes, while a shot at f/14 and 4s made them look thinner or less visible. Why does this happen?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
8y ago
2 Answers
16
The use of a large diameter, f/3.2 aperture allowed you to set the shutter at ½ second. You captured snow as it tumbled down. The shutter speed is insufficient to freeze the falling snow. The flakes you captured were moving, thus the camera recorded them as streaks. More importantly, the f/3.2 aperture yields a shallow depth-of-field. If you look closely, the snowflakes as well as the car grill are out-of-focus. The blurred snowflakes appear larger and indistinct because they are out of focus.
The shot at f/14 has expanded depth-of-field. The snowflakes are rendered sharp. However, the shutter was open for 4 seconds. The snowflakes being in motion imaged as an elongated but in-focus streak. The fact that the streak is in-focus reduces the width of the band.
Originally by user44949. Source · Licensed CC BY-SA 4.0
user44949
8y ago
0
Generated from our catalog & community — verify before relying on it.
It’s mostly not the aperture itself making snowflakes bigger. The main cause is the shutter speed change that comes with different apertures.
At the wider aperture, you used a much shorter exposure. Falling snow had less time to move, so each flake made a shorter blur trail and looked brighter, thicker, and more obvious.
At the smaller aperture, the longer exposure let each flake travel much farther during the shot. That spreads the same light over a longer streak, making each flake appear thinner and sometimes less noticeable.
Depth of field also contributes: at f/3.2, the shallower depth of field means many flakes are out of focus, and out-of-focus flakes can look larger and softer. At f/14, more of the scene is in focus, so the streaks look narrower and more defined.
So the effect comes from a combination of:
- shorter vs. longer exposure time
- motion blur length
- shallow vs. deep depth of field
If you want snowflakes to look distinct and “big,” use a faster shutter speed; if you want longer snow streaks, use a slower shutter speed.
Recommended products
UniqueBot
AI8y ago
Your Answer
Related Questions
Does aperture change facial features in portraits, or is it focal length and distance?
What lens and settings create shallow-depth night street portraits in snow?
Why do exposures vary in Aperture Priority when I change aperture?
How can I make falling water droplets look sharper?
Why do my photos look softer at f/22 than at f/14 on a tripod?