i went to RAF Duxford a few weeks ago for an airshow so i took my camera as you do 
anyway the biggest lens i had was a 70-300mm so i wasn't expecting much and as i expected when it came to the show i was at the end of the lens most of the time so now i have been looking for a little extra in focal length but without the cost of a big lens so i was thinking of a 1.4x Teleconverter but I'm not to sure if i would be wasting my money or not so i just wanted to ask you guys for your opinion
my gear is a Nikon D90 and a 70-300mm 4.5-5.6 VR and some of the pictures i took are here http://www.flickr.com/photos/thobbs95/sets/72157622330770428/ most of the planes in the air were all cropped and as you can see there not the best and most where done in lightroom as it was a very grey and overcast day.
anyway the biggest lens i had was a 70-300mm so i wasn't expecting much and as i expected when it came to the show i was at the end of the lens most of the time so now i have been looking for a little extra in focal length but without the cost of a big lens so i was thinking of a 1.4x Teleconverter but I'm not to sure if i would be wasting my money or not so i just wanted to ask you guys for your opinion
my gear is a Nikon D90 and a 70-300mm 4.5-5.6 VR and some of the pictures i took are here http://www.flickr.com/photos/thobbs95/sets/72157622330770428/ most of the planes in the air were all cropped and as you can see there not the best and most where done in lightroom as it was a very grey and overcast day.