CNN training on Different Datasets
I suggest you to use as much data as possible. If the images are coming from two different cameras, it could be an original way to fight overfitting. I would use both datasets, and operate a train-validation-test split that is transversal to both.

Additionally, since the dataset is small, I strongly enourage you to use lots and lots of data augmentation, which is a very powerful technique to artificially increase the size of your dataset and fight overfitting.