Why do photos get darker at wider apertures on my Nikon D5100?
Asked 9/20/2019
4 views
2 answers
0
On my Nikon D5100 with a 35mm f/1.8 lens, I expected a lower f-number (wider aperture) to make photos brighter. But I was seeing the opposite: shots at larger f-stop numbers looked brighter even though I thought shutter speed and ISO were staying the same. What camera setting could cause this behavior?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
6y ago
2 Answers
3
... my photo with larger f-stop numbers is brighter than the photo with smaller f-stop numbers (the ISO and the shutter speed remain the same).
Since you refer to "f-stop numbers", it appears you know how F-numbers and aperture size are related to each other. You also appear to understand the effect that changing F-numbers should have on the image. When ISO and shutter speed are kept constant, it's normally expected that increasing the F-number reduces exposure, which causes the image to become darker. This is opposite what you describe.
Brighter images taken with smaller aperture sizes could be explained by:
- Changes in scene lighting.
Settings that alter the processing of images, such as Active-D Lighting. The following page has sample images that show how Active-D Lighting affects the brightness of images:
- Nikonites: Active D-Lighting For the D5100
Changes to shutter speed and ISO. However, you state they did not change in your case.
Originally by user75526. Source · Licensed CC BY-SA 4.0
user75526
6y ago
0
Generated from our catalog & community — verify before relying on it.
Normally, with the same shutter speed and ISO, a lower f-number (like f/1.8) lets in more light and should produce a brighter image. A higher f-number (like f/8 or f/16) makes the aperture smaller, so the image should be darker.
If you’re seeing the opposite, the most likely cause is that another setting is changing exposure behind the scenes. On the Nikon D5100, Auto ISO can do this by adjusting ISO and sometimes shutter speed automatically, even when you think exposure is fixed. Other camera processing features can also affect brightness in JPEGs.
In your case, the issue was Auto ISO sensitivity control being enabled. Once that was turned off, the camera behaved normally.
So yes: your understanding of aperture is correct, and the camera itself was likely fine.
Recommended products
UniqueBot
AI6y ago
Your Answer
Related Questions
Why does Live View exposure simulation look too dark at 1:1 with the Canon 100mm f/2.8L Macro?
Why does my Canon 5D Mark II stay at f/1.8 in shutter priority and still give dark photos?
Why does a dark room photograph look too bright, and how can I keep the shadows dark?
Why are my Canon 70D photos suddenly very underexposed in daylight?
Canon AE-1 Program aperture only stops down to f/4 during depth-of-field preview