[Guest]

Here are a few ideas.

First look through your pics and see if really you need all this f/2.8 glass on a trekking tour. lowlight landscape shots should require small apertures anyway, while for campfire shots you could take the 50 1.8.Thus, I would guess you dont need f/2.8 when trekking.

So here are my suggestions:

1. get a Canon 550D or 600D. Much lighter than the 7d and same IQ(500g vs. 800g, you save 300g)

2. get a canon 10-22 instead of Tokina 11-16, essentialy same IQ, but of course slower.(385g vs. 560g, you save 175g)

3. dont carry the sigma 17-50 OS, take canon 18-55 IS which offers comparable sharpness. Everything else can easily be fixed in post as you shoot raw anyway.(200g vs. 565g, you save 365g)

4. since there is no equal alternative to 70-200 f/4 IS I'd keep it if you use it enough times on your treks.(55-250 IS is actually not too bad, I'd consider it if I didnt shoot at the tele end too much)

5. if you need speed, add a 50/1.8 (130g)



In total you save 710g of weight, which is quite a lot. If you replace 70-200 with 55-250 you save an additional 400g. Remember, if you go 4/3 route, you loose about 1 stop in noise performance. You might then as well by slower and lighter glass and compensate by increasing the iso.

Dont worry too much about IQ, since you shoot raw. All of the lenses mentioned are for most practical purposes as sharp as your current gear. CA and vignetting etc can all be ironed out later. Finally, if you dont print big eg. 20x30inch or 50x75 cm, you dont really need the best glass anyway.