Some great advice here and for now, I think you have managed to pause the start of my LBA journey..
As a noob, I too find the wealth of old glass out there intimidating and confusing, and there is a whole load of knowledge behind those lenses that reviews just dont show..
Because I had so may questions and there was so much I didn't understand, I decided to hold off for now, just use the kit lens and see how I go..
From a noob point of view some of the questions I had were
With an 18-55 lens, why buy anything in that range as I have it covered..
Is the picture IQ equal at 18 and then at 55, or is it only sharp at say the middle (35)?
It seems that the only cheapish lenses are manual ones A or M, as soon as you look at FA series the price rockets..
The DA lenses were designed for digital camera's, does this mean that anything less than a DA is a compromise on quality?
When a lens lists Appertures say for instance F3.5 - 5.6 - is that the range of the lens? I get that if one apperture is listed, than that is probably the widest it will go, but when more than one is listed?
I was so close to buying the Lester A. Dine 105mm f2.8 Macro (alias Kiron) as I saw everyone raving about this Lens, and I do want to do ALOT of macro work as it fascinates me and I sort of figured that these don't come up that often, so it might be worth it as the first keeper for my collection. The thing that stopped me is that for a little bit more - I could get a DA macro from Pentax..
How does old quality glass compare to the newer stuff?
OK, I get fungus isn't good in anything, but why does oil in a lens cause problems, as I have seen a few mentions suggesting that a lens might need lubricating?
The lens naming scheme - when searching for lenses in ebay, there seems so many ways to name lenses in any order that I have just started to search for focal length and leave the rest so I dont miss any..
Why isn't there a list or top ten pre DA lenses as a sticky or guide as to what are good lenses? There is so much to go through to try and find out whether a lens is good. Read the review, it's ok, then see a post about another lens, and the whole process starts again.
A list of well regarded lens for beginners would be a great idea. People buy into Pentax for the old glass as a cheaper way to build up a lens kit while they learn, and as they get better they can upgrade. It would be a great idea to have a sticky listing some old but good lenses, so people can go off and search straight away and know that while it won't be great, they will get a half decent lens to learn on while they work out what to do..
For now, Im holding off, sorry for the barrage of questions, but these are all things rattling around in my head, I know in IT when I see the Grads coming in now, I have to try and remember where they are starting from and just how much they don't know that experience gives you, and it's the same in this I think!
Having said that, this forum and the pentaxuser one were a big decision in why I went Pentax as I liked the feel of them and the tone of the comments.
I think I have a classic case of 'noob elephant in china shop' syndrome, so Im taking a deep breath, stepping back and promising myself to just use the kit lens for 3 months, then exposure plot and see what I need before i buy
Unless another kiron macro comes up