i wouldn't go that far to say that photographer = slacking lah...
digging shell-scrape is not exactly the most heroic kind of soldiering as well... if that was so, u would find lots of gallant soldiers at any construction site.
for sure, being the unit photographer is unappreciated sai kang. but someone has to do it. THAT is what soldiering is all about - you DON'T get to choose the sai kang all the time.
imo, i don't think its entirely slack also... the "risking your own equipment" part is totally valid. dust, mud, sudden downpour, etc etc. u will also have to do a fair bit of running around to get the shots u need. i don't think its that slack at all.
lastly, it may not be so clear cut whether u have to join the training if u're the photographer... the most frustrating scenario, they may ask u to draw everything AND bring your camera... they may pull u out to shoot once in awhile, but other times, u follow the rest. (it can be done and it has been done before)
its really your call whether u're willing to do it if u had a choice, or whether u're being definitively arrowed and u have no choice.
if it was me, and i could choose, i wouldn't want to do it.