what is the preferred format to take photos? i understand 4:3 will result some cropping when printing in 4R format etc while 3:2 will fit nicely without so is there any standards or consideration when deciding which format to choose?
the best aspect ratio for you, is depends which final output you usually want it, if you need to print 4R, stick to 2:3, you need to do cropping for each images is not in 2:3 ratio paper size.
if you choose to have 3:4 format, you need to print a size similar to 4R, you need to print it in DSC4R or jumbo 4R or super 4R as whatever the labs call it, unless you crop it into 2:3 ratio for a 4"x6" print.