RSync exclusion

[Jos Chrispijn]

I have a local folder called /files/
In my daily backup event I create as per day a backkup folder that 
contains this /files folder including all its sub folders

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rsync -avrz -e ssh /files/ backupr at x.x.x.x:/vol1/FreeBSD/$DATE/

In this /files folder, amongst others, I have another folder called 
photos: /files/photos

What I now would like to do is sync the /files folder with an exclusion 
on the /files/photos folder
Reason for that is that this /photos subfolder contains 12 gb on photos, 
which I don't want to have in a daily archive (takes too much disk space 
on a monthly basis).
I will syn them on a daily basis to a fixed remote folder (where only 
the updates will be appended).

Can someone tell me how I can do that on one command line?

thanks in advance,
Jos Chrispijn