Will Nikon sb 26 work on your Nikon d7100?

Yes, the Nikon SB-26 flash will work with the Nikon D7100, but it will be in manual mode only. The D7100 does not support the older Nikon CLS (Creative Lighting System) features that the SB-26 uses for automatic flash exposure. To use the SB-26 effectively, you'll need to manually set the flash power and adjust settings based on your shooting conditions.