What kind of magnification will the 28mm be reversed, also quite a lot right?
Might be a good solution instead of stacking.

Oh wow thank you, will put them surely on my list they look great.

I already have ordered Cowboy Kate, Strip Sessions & Guy Bourdin, will surely look at the rest on a later date, need to be careful money wise these months

Yeah might need to make that a sticky and put lenses in it as well, was also planning to link all of them to the right wikipedia site but didn't had the time to do that.

maybe will do that tomorrow... maybe, we will see

vignetting might be a problem and you need tons of light so a flash would be handy.

I would reverse mount the Sirus 28mm on top of the pentax A 35-80
You will get a 2.85 magnification then. For more you could resverse mount it 28-200, it might work but dont expect much quality, the 35-80 combination would be better.

Try to get prime lenses instead of zooms, 200mm f/4 are quite comon and are reasonable priced so keep an eye out for them

This is a beginning link

For lens variation this a site link

CPPAA - Common Pentax Photography Abbreviations and Acronyms link

Was that helpful enough?

And here comes one of the problem with modern sensors, most of them have en UV coating on the sensor screen so they block Infrared light so you need to replace/remove that as well.

I've a IF filter for the K10D but it isn't adapted so need to take photos of 30 seconds at f/5.6 during a sunny day...

Uv filter will do that and always has but since many lens coatings and even the sensor screens have coatings the difference they make becomes smaller.

Like Womble I also use a polariser as much as I can, even indoors if light allows it.
Polariser really cuts down the have and reflections makeing colours more vibrant and brilliant. You need to get some good pols though, cheap ones aren't always colour neutral so really get the best you can get get.

Altight I want some info about which 50mm lens is the best, good luck searching it's a long list.

Also with wiki for example with a lens, you can put the facts and numbers down and then you as user can write under it your comments on the lens. That part will be personal but anyone can write there own review of the lens so it's fair and you more sides. It shouldn't be a place to discuss.

You also have the space to upload photos so that would also be very handy

It might seem a bit cold but I can see that my answers are getting shorter and shorter every time I write them down, i find that colder to be honest. It's a personal problem but I believe I'm not the only one.

What we do with most questions is write down our own experience about some photo equipment so why not write down your own review about it and use the wiki to display it, just like Pentaxforums have for their lenses.
It works quite well and I always look there for some feedback on a lens.
This can of course also be applied on flashes, cameras, tripods and maybe even filters.
Simply what you like about it and what not.
Someone can draw their own conclusions on that and would be able to ask specific questions.

https://www.pentaxuser.com/forum/topic/Pentax-1770--versus-the-Sigma-1770--Quick-user-experience-required-12757

You did looked there right before you placed your question?
I'm really not mad it's just that I think you will find what you need there or do you want a 16-45 vs 17-70 thing?

they are both equal in image quality, believed that the 17-70 is a bit less sharp but you have far less aberations then with the 16-45.
The 17-70 has a far more usefull range also, it's a no brainer to behonest if the price wasn't that much higher then the 16-45.
For the price you would surely love the 16-45.