Here is a spec comparison
Compare the Nikon D300 vs the Pentax K-50
Pentax do weather sealed lenses think they are badged WR. They do the stock 18-55 but also an 18-135 which may be more versatile.
Pentax K-50 with DA 18-135mm WR Lens - low shutter count - extras!| eBay
This also looks like a nice package.
Nikon D300 Digital SLR Camera 18-70mm Lens Kit Many Extras| eBay
Those are the 2 I'm actually looking at on eBay mate! It's going to boil down to D300 with a load of extras (cards etc) vs K50 with waterproof body and lense and better sensor, especially in low light, but no extras.
I'm leaning toward the K50. Would you do the same for only £100 more as well?
Difficult one, there is a lot smaller market for Pentax dslr’s in the uk which is dominated by canon and Nikon so there tends to be fewer about on the sh market. So you get more for your money with the Pentax but may be more difficult to sell on if you decide to do so later.
Review of the 18-135 lens
SMC Pentax-DA 18-135mm f/3.5-5.6 ED AL DC WR Lens Review
And the k50
Pentax K-50 Digital SLR Review
LCE Have a k50 with the shorter 18-55 wr in if you want to buy from a shop with a 6 month guarantee.
Used Pentax K-50 DA 18-55mm f/3.5-5.6 AL WR| London Camera Exchange -Worcester
Aah cool ok. I may well keep the camera after my trip, so will make an offer on the K50. I'll let you know which one I'll end up with! Thanks a lot for everyone's help!
The Pentax is a great camera, I'm not sure autofocus is up to the D300 standard though. Sensor wise it's better, but if you want to get things on a budget/better value then you may struggle with Pentax as there's not as much used gear around such as lenses.
For backpacking I wouldn't want the bulk of a crop sensor DSLR I'd choose a Micro 4/3rds system as it has a slightly smaller sensor but (generally) a smaller, lighter body and lens.
For example
Used Olympus OMD E5 Compact System Camera - mpb.com
and
Used Olympus 14-42mm f/3.5-5.6 II lens - mpb.com
I’d have suggested that too but the OP is keen to have good high ISO performance.
Sure I read the sunset/low light requirement too but I've been pretty happy with my Olympus cameras compared with what my old Pentax K100D could do.
Having a really high ISO available isn't (IME) that useful if you don't like the results.
I'm a big fan of the stablisation in my Olympus cameras as you don't need to push the ISO into the thousands.
I objected to lugging my DSLR around on day trips so the idea of carrying it along with everything else I needed for a trip in a backpack would be horrifying.
I also find my little Olympus is a lot easier to tuck under my jacket when walking past crack smokers in Porto or pimps arguing with Johns in San Francisco - real life examples of taking a wrong turn as a tourist data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
I was having similar thoughts particularly when high iso and DR are the priority, you're right to clarify that DXOmark scores can exaggerate differences but even then APS-C sensors have definitely improved quite a bit since the D300.If AF performance was a priority then I'd say the D300 was a better choice at the cost of IQ but that's not the case.
I've very limited experience with Nikon weather sealing but I've not been impressed with it, I have the D700 which is mostly the D300 body with a bigger sensor and it had problems in the first year which Nikon put down to water ingress.The camera had never been near water as I didn't want to risk it but Nikon wouldn't back down and charged me for the repair which I was also annoyed about.I'll admit that's just one case so it makes me a bit biased against Nikon for weather sealing, I used my Olympus DSLRs in heavy rain and poor conditions but neither camera skipped a beat as I'd expect from weather sealed cameras.
John
Nikon weather sealing in the high end bodies is actually very good, I can't help but feel Nikon fobbed you off tbh, especially if your camera had never been near water data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
I agree about Olympus though, they're excellent, mine have been out in heavy rain and never batted an eyelid.