Karim D. Ghantous
Well-known member
Back in July I did a personal experiment on an overcast day. Finally, I got around to posting it. ;-) I wanted to see the difference between the dark clouds and the ground. I took some photos and screenshots with my phone (iPhone 5S).
1. I metered the green grass on the ground.
2. I metered the darkest cloud I could see.
The difference is 4 1/3 stops (roughly).
3. I took a photo of the grass with the camera app, locking exposure.
4. I pointed the camera up at the sky and took a photo, leaving the camera in HDR mode. This is the original exposure:
5. This is the HDR exposure:
6. I noticed that part of the sky was open. So I metered it. The light meter app says that it has the same value as dark clouds:
7. I once again locked exposure on the grass at my feet, then pointed the camera at the sky. Original:
8. HDR version:
The iPhone is not known for its ability to handle highlights. The point of the exercise was to see the difference between sky and ground in overcast conditions. It's more than I thought. Modern negative film can handle at least five stops over, and the Dragon (and by extension, the Helium) can as well (even more when rating at higher ISOs, obviously).
I hope this is as interesting to you as it is to me.
I did another test just yesterday, comparing a clear evening sky to the ground, after sundown. I'll post that tomorrow.
1. I metered the green grass on the ground.
2. I metered the darkest cloud I could see.
The difference is 4 1/3 stops (roughly).
3. I took a photo of the grass with the camera app, locking exposure.
4. I pointed the camera up at the sky and took a photo, leaving the camera in HDR mode. This is the original exposure:
5. This is the HDR exposure:
6. I noticed that part of the sky was open. So I metered it. The light meter app says that it has the same value as dark clouds:
7. I once again locked exposure on the grass at my feet, then pointed the camera at the sky. Original:
8. HDR version:
The iPhone is not known for its ability to handle highlights. The point of the exercise was to see the difference between sky and ground in overcast conditions. It's more than I thought. Modern negative film can handle at least five stops over, and the Dragon (and by extension, the Helium) can as well (even more when rating at higher ISOs, obviously).
I hope this is as interesting to you as it is to me.
I did another test just yesterday, comparing a clear evening sky to the ground, after sundown. I'll post that tomorrow.