I don't know the lit. translation of the title from Jpn. To me the Eng. meaning refers to Takaba's job. He is looking at Asami through the lens of the viewfinder of his camera and he is the prize he wants to catch. Asami being the loveprize. I hope that helps. Others may see it differently.
That's just slankwords by ayano sensei for Asami , he's fall in love with akihito in first sigh through his viewfinder ... http://2.bp.blogspot.com/-EH7dxjg_Xwo/V-8xb23cZQI/AAAAAAAUAEg/082R-aFPotE/w1600/1.jpg read at the last page when asami leaving while looking at him over his shoulder ... there wroted “ YOU ARE MY LOVE PRIZE IN VIEW FINDER ”...
Hope this can help you , sorry for my poor english
Just to be clear: Neither Asami nor Akihito actually says these words "You are my love prize in viewfinder" at any stage. The only reason it is printed at the end of that page is simply to let readers know that's the title and that this is the end of the chapter/the volume. Because if you look closer, it says "You are my love prize in viewfinder END", so this is merely to indicate that this is the end of that section, nothing more.
You are welcome.
English is not my native language but I can speak and understand it but I can't understand the name of this manga like loveprize in viewfinder what does it mean ╥﹏╥
I'll be very grateful if someone told me the meaning of it