I have heard people say they like to photo and post merchandise staight from the unit before they move it or just leave it there and sell from the unit to save time. I never really understood this because everything I get needs to be inspected, cleaned, & researched before I post it for sale. There are very few things I find in a unit that are "ready to sell" the way they are found.
If I rent a purchased lkr for the first month ($30 deal) it would be because of quantity involved and shortage of space in other places I store items, and I definitely photograph items there after checking them out. Most of the spots I would rent are large lkrs and have electricity for checkig items.
Since I don't have a smartphone or an iPad with a camera, I really can't comment on the quality or capabilities of their cameras, but I know for the kind of photos I place on eBay/Clist that the macro capability is important. As I said before I might post 3 to 20 photos in a listing and they are all done with html within the text, not using the standard approach provided by eBay/Clist.
My best camera can focus as close as 10" on a label on a motor, a box, etc. Having a photo which can show the texture in a canvas bag (as an example) is important to me. Sometimes I have to NOT use a picture because too much detail is shown...no one in real life can see the tiny imperfections that a real close-up shows.
So aside from the "convenience" factor of the phone/iPad shots, I'll stick with what has worked for me.
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On a similar note my daughter who is going to China on a two-year teaching assignment tells me that her iPad with a camera can easily connect with Skype to other iPads through some super-connect program that dials directly to other iPads, where she and I have to have some pre-arranged agreement for a Skype call to my web-cammed laptop. THAT would seem to be a real advantage to a mulit-purpose device.
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I guess I am just old-school when it comes to having dedicated devices for dedicated purposes. On a hike my camera with 10x optical (and much-more digital) zoom can take a quite close-up picture of an animal at some distance; I doubt a cell-phone cam can do that, though for "snap-shots" it can't be beat.