Question about F stops

[TCav]

Originally Posted by Outhouse

Well, I have Sony and I am pondering how much better their 1.4 is vs. their 1.8. I suspect enough to warrant the price difference

Sony's 50mm f/1.4 is a 'Full Frame' lens, while its 50mm f/1.8 is a 'DT' (APS-C only) lens, so you can't make a real comparison between them that way.

If you're shopping for a 'Full Frame' lens, the 50/1.4 is all there is, but if you're looking for a 50mm lens on an APS-C body, the 50/1.8 is better.

That is, except for that whole 2/3 f-stop thing, for which there is no substitute.

[SIMON40]

Here's a link reviewing the f/1.8 Sony lens- with a direct comparison to the f/1.4 further down the page..
http://kurtmunger.com/sony_dt_50mm_f_1_8_samid147.html