A. Hitler and propaganda minister Joseph Goebbels during a walk at Hitler’s mountain retreat on April 12, 1943

Fresh mountain air...

Bit like the start of "Lohengrin" ?  No, not really ... JR.

"Too big for both of us ... "

The Fuhrer plays the throw-the-ball game with Blondi.  Hitler does not look the best, which suggests that this was from Summer, 1944.  The snapper may have been Eva Braun, who had worked in photography in earlier days, and remained an enthusiastic and quite skilled amateur photographer during her years with the Fuhrer.

Eva herself did not like Alsatian/German Shepherd dogs, of which Hitler had several.  She owned a pair of Scots Terriers herself.  Best regards, JR.