Quote:
Originally Posted by KJ Smith As a general rule, overexposure will cause more grain. |
I've found that overexposure can cause a lack of detail. It's
underexposure that causes grain to be more apparent when corrected for, either in the digital or chemical darkroom.
If you use the meter from a dSLR for any scene that requires more than a second of exposure, the film will likely be underexposed significantly when using the same settings. That's what reciprocity failure is. The longer the light takes to affect change on the film, the less effective it is. Imagine pouring a cup of water into another cup. With film water, if it took an entire second for the transfer to complete, only half the water would reach the second cup due to reciprocity failure. If pouring the water took just a 100th of a second, almost no water would be lost, therefore no correction would be required. If it took 10 seconds to transfer the water, only 1/3rd of the water would make it. ect..
The amount of correction depends entirely on the film used and the exposure length. There are charts online for quite a number of films that allow you to quickly calculate how much more light you'll need in order to get a correct exposure. There are even apps for smartphones that help with this.
So, it's most likely that the grain we're seeing here is due to grossly underexposed images that had to be corrected for. Bringing up the exposure of underexposed images is the #1 cause of grainy images.