Favourite Lens?

I don't have (and I'm unlikely to get) full frame. However, on APS-C (K-3 and K-70) the lens on the camera for most of the things I shoot is the D-FA 28-105 - amazing quality for the lens type and size - with the 21 Limited in a pocket (or on the other camera), in case a wider view is required.

Philip

It's the D FA 28-105mm for me too, also on aps-c. A very versatile range, which I admit is mostly employed at the longer end for close ups and portraits.

I bought it with a view to a future on Full Frame, as I read it holds IQ right to the FF edges, with the price of a little corner vignetting.

My favourite is usually the last one I bought. Until the next one.

I have a few:

DA*50-135 for general walkabout use

DA*300 with TC for wildlife, flora and fauna

Pentax-M 28mm F3.5 for landscapes where the limited width allows

I am also quite fond of the DA L 55-300 and the 12-24, but these get used a bit less nowadays.

Regards
David

My favourite lens is the one I have with me that allows me to get the shot I want...

Lenses I have a fondness for and tend to carry about a great deal...? the DA* 50-135mm for digital (although I am loving the FA31mm so far). On film, I like my K-series set: 30mm f/2.8, 50mm f/1.2, 85mm f/1.9, 135mm f/2.5 and 200mm f/2.5. Let's not start on rangefinders...

K.

I think my FA*300 F4.5 must be my favourite lens on Pentax. Bought new in the 90's, my most expensive lens up to that point. I added the DA*300 just over a year ago but the FA* is still with me and the DA* is just about to go....
2nd favourite is my, new to me last year, Sigma 180 F3.5 macro. It's a big lens but it's a beauty. No idea why anyone would sell this.
These 2 lenses will probably mean I keep at least one Pentax body in the future, even after moving away from Pentax!

Wide: Pentax SMC K 28mm f2.0 - this lens truly has something special about it.

Standard: Pentax DA* 55mm f1.4 - designed as a short tele lens for APS-C it's superb on Full Frame too!

Portrtait: Pentax A* 85mm f1.4 - this one just about has the edge over the other truly great Pentax portrait lens. Great for portraits but equally great for landscapes.

Telephoto: Pentax F* 300mm f4.5 - always surprises me with how good it is at maximum aperture, in a compact and beautifully made form - this one just edges the superb Pentax DA* 60-250mm f4.0 (which is a more flexible lens).

If I was forced to have just one lens for each format then I would choose....

APS-C : Pentax DA 35mm f2.8 Limited Macro

Full-Frame : Pentax DA* 55mm f1.4

I would say the Sigma 17-70mm f2.8

I really wanted to say the Pentax 18-135mm but unfortunately I can't because unless I'm unlucky I don't think it's a particularly good lens. Move it away from the wide angle end and it's fine. In fact at 135mm it's probably the sharpest lens I have. But at 18mm it's quite poor indeed. Wouldn't be so bad but it's the wide angle end I use the most.

You must be unfortunate dangie. What you are seeing is the reverse of how zoom lenses usually work, with wider angles performing better and some of them completely giving up at the long end. I would try another 18-135mm and see how that fares.