Compared with the D300:
Dedicated Live View button, which I use all the time to set white balance.
how is this better performance when the D300 has its own dedicated WB button
Front FUNC button can call My Menu, which I use all the time for selecting Auto Iso.
same as above, dedicated ISO button
It's lighter.
its made of plastic, drop it and you might need a new one
It's smaller.
thats ok if you've got small hands
It's cheaper.
and it feels it !
It has better detail in high ISO JPGs due to less noise reduction.


It can record video.
yes it can, but if your serious about this you'd be better off buying a camcorder
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The D300S may have addressed some or all of these differences.
Personally, I couldn't justify the extra cash for no improvement in image quality and a reduction in certain features in exchange for increased size and weight. However for those who need slightly more AF performance (sports?), they know who they are. If you have to ask, you probably don't need it.
no improvement in IQ ? the auto focus will give you a better keep rate, unless your subjects are still
As far as weather-sealing... this attribute is difficult to quantify; I don't know how you can positively confirm your camera has good weather sealing apart from leaving it outside in a heavy storm. Certainly I've never heard of a D90 which had problems due to weather. I'd like to see some objective data on this. The panel joins on the D90 are as tight as you like; again I'd like to see some info on exactly what improvements the D300 makes to give its legendary Weather Sealing.
see above post.
If the D300 is made of magnesium rather than plastic, this could account for the higher price in itself. You could make a camera from gold if you wanted: it would be very expensive. It wouldn't make better pictures though.
personally i think the D300 is worth the extra for the auto focus alone.
another thing is unless your a novice you will not need the idiot modes of the d90 ( landscape, portraite, close up etc ) even when i started with my D80 i never used them.
just my humble opinion !