The differences are a little bit obscure in color pictures,
so see the pictures in black and white.

Now, do you see the differences?
Since we generally light subject from the side when we take flash photography with a TLR camera, it will give you different impression when lighting from the front.
As you can see in the pictures above, contrast is emphasized in the right picture as is mild in the left.

These lighting were made possible by the accessory shoe name MJ Accessory Shoe that was designed exclusively for RolleiFlex TLRs.

As shown in the right figure, the pictures were taken with the accessory shoe with the flash set on the view lens, which enables for the best camera for portrait photography to use the compact flash, and also it is very useful for fill-in flash.
Some of the famous photographer use same technic. They say it will help creating natural descriptions of subject in daylight, and use the adapter to set the compact flash on their Hasselblad.
The accessory shoe used in this page is MJ Accessory shoe manufactured by Mediajoy.

Item's datails are Here.