I started to fancy prime lenses ever since I own the 5D. The older generation (back in 80s and 90s) of EF lenses were designed for 35mm film SLR. There's a series of (non-L) prime lenses in the EF range such as 20/2.8, 24/2.8, 28/1.8, 28/2.8, 35/2, 50/1.4, 50/1.8, 85/1.8 and 100/2. These prime lenses are fast (at least having aperture of F/2.8), light in weight (between 200g and 500g) and cheap (less than RM2000). If you wish to travel light, consider bringing one or two prime lenses. I'm pretty sure the total weight (and price) would still be less than a EF24-70mm F/2.8L USM. Of course you lose the convenience of changing the focal length in just a twist, but people usually believe that using prime lens will drive the photographer to think more, compose more carefully and shoot better.
Apart from the weight/size/price, prime lenses allow me to shoot a photo under low light condition without using a tripod. Of course if you have the luxury to shoot with a tripod, that would be the best. Stop down the aperture to F/8 or even smaller i.e. F/11 to get more DOF and use the lowest ISO setting for best image quality. The trade-off which anyone can think of is the inconvenience, not to mention certain locations disallow the use of tripod.
Generally, on fullframe bodies, 20mm - 24mm are considered ultra wide angle; 35mm is considered wide angle; 50mm is considered standard; 85mm - 100mm are considered medium telephoto. For APS-C bodies, 20mm - 24mm are considered wide angle, 35mm is considered standard; 50mm is considered medium telephoto; 85mm - 100mm are considered telephoto.
For APS-C body starters, I would highly recommend the EF35mm F/2 lens. With an effective focal length of 56mm, it can be used as a walk-around lens. The minimum focusing distance of 0.25m allows close-up yet capturing the blurred background at F/2. Very versatile. The price is just nice, around RM1000. As for half-body portrait, the EF50mm F/1.8 II is a steal at RM300. With an effective focal length of 85mm, you can capture half-body portrait without distortion at a reasonable distance to maintain communication with your model. If you feel the F/1.8 version build quality isn't up to the standard, you may consider its sibling EF50mm F/1.4 USM at a higher cost of around RM1300.
My personal favourite combination of these primes depend on the type of the trip. For landscape and portrait, I migh couple 24/2.8 with 50/1.4. If I just wish to bring only a single lens, 35/2 could be an all rounder. How about coupling 50/1.4 and 85/1.8 for just portrait? Too many combinations! But I will always try to limit to 2 lenses at once. Either of these combinations would easily fit into my DOMKE F-5XB shoulder bag.
If you wish to know more about these prime lenses, please read this article "
Ugly Ducklings: the early EF primes".
Just for price comparison purpose, checkout how many prime lenses you can buy from a single high quality L-series zoom lens:
EF24-105mm F/4L IS USM (RM4500) = EF24mm F/2.8 (RM1500) + EF35mm F/2 (RM1000) + EF50mm F/1.4 USM (RM1300) + RM700 of cash
EF24-70mm F/2.8 USM (RM4800) = EF24mm F/2.8 (RM1500) + EF35mm F/2 (RM1000) + EF50mm F/1.4 USM (RM1300) + RM900 of cash
EF70-200mm F/2.8L IS USM (RM6300) = EF85mm F/1.8 USM (RM1400) + EF135mm F/2L USM (RM3300) + RM1600 of cash
EOS5D, EF24mm F/2.8, F/2.8, 1/40s, ISO800
EOS5D, EF24mm F/2.8, F/2.8, 1/40s, ISO800
