I think that is what 99.999% of members here would suggest too, but you asked specifically about a walkabout prime. Perhaps you're not sure what the term prime lens means? It's a lens having a fixed focal length (28, 35, 50, 100mm), as distinct from a zoom lens which has a variable focal length (18-250mm).

You already have (or had) a DA16-45mm lens which is an exceptionally good walkabout lens.

Perhaps the heat was too much for you that you felt it necessary to end with this.

What information do you hope to gain from your poll?

The 'standard' 50mm on 35mm was considered to be a walk around prime. An APS-C DSLR would need a 33.3333mm lens to have an equivalent field of view.

Since nobody makes a 33.3333mm lens, the 31mm Ltd or any 35mm lenses are closest.

One main difference between the two lenses is that the DA 55-300mm is optimised for the APS-C sized sensor, the FA 80-320mm is for 35mm sensors.

I've not used the DA lens, but I had the FA one and found images quite soft at the long end where I used it most. Up to about 280mm it was fine.

This might look good on your front lawn.

I think many users of Pentax wireless flash technology are possibly ignoring the makers specification. Wireless flash of the technology employed by Pentax flashes is recommended for use at a maximum range of up to 4 metres.

Above that distance, a cable/radio/IR trigger mechanism is required for reliable operation.

These Cactus V5 units seem to be the business and I may switch from my recently bought Seculine Twinlink system, but only if I think I might need long distance shutter control.

I've found Lumiquest's products to be very good. I've not used their gels though.

The AF540FGZ is bound to be of a similar size to any other makers flash having a similar power.

The above links work.

Leather, fungus, eventually?

This is the current datasheet for the AF160FC ringlight. It shows that now, only 3 adapters are included, 49, 52, & 58mm.

That said, if you look at the second page of the same datasheet, it mentions second curtain synch, wireless flash, zoom & swivel reflector, catchlight panel, and a few other capabilities that are not included in this flash.

So I wouldn't believe a word of it if I were you.

It is a very good flash though. I wouldn't be without mine.