Bjolester Sir, please do not confuse the speed of a lens (f1.2, 1.4, 1.7) with sharpness, bokeh, CA, distortion, ... or other other picture qualities. This kind of photography is best done on a tripod, so any UWA Lens as slow as F4 is good enough. The cheapest UWA is the Sigma 10-20. It also happens to be the most praised for every known lens test. The Sigma is much much better than the Samyang or for that matter any SWA lens at its price point, size and weight. Please see the Pentax Forum USA - search for this lens as there is a a specific thread for this lens. You will be amazed and blown over.

Hello Spacus, you have some great advise above from the beautiful Pentaxians on this Forum. I am responding as I have the Sigma 70-300 APO and a K20D bought in early 2009 from B&H New York.
a) the K20D remains one of the most popular DSLRs yet. There is some truth in the saying "you are buying someones reject on e(vil)Bay), if you have bought yours "pre-ownwed". Do it could be defective. It is far superior to the K10D and totally a different machine though looking exactly similar - very deceptive. As someone said above RESET the camera for all Menu options. Check the sensor for dust and dead pixels - read the online Manual.
b) JPEG Setting for the Sigma 70-300 APO: not a very sharp lens, so set it to Bright, Sharpness +3 Fine, Contrast to +2, Hue and Saturation 0 - use Fn button. Set ISO to Auto but between 100 to 800 ISO. WB Auto. Metering Mode Matrix. Auto Focus Point Center. lens Auto Focus System AF-S. Shake Reduction ON. Please use Av or Tv mode to start with so that you do not have too much variable to adjust as in M mode - please follow this to begin with. Set the JPEG Resolution and Quality to the Highest - Recording Mode menu. Link AF Point & AE, AE-L with AF Locked. Slow Shutter Speed NR to Default. High ISO Noise Reduction to OFF.
c) Do not use Live View for photo taking - crude on the K20D.
Take some photos at the 70 to 100 mm end on your Sigma 70-300 APO, both hand held and on a tripod - suggest use a large multi colored toy on your terrace for good sunshine.Post the photos here. Good Luck.

I think two very important points have been left out: a) the Sigma 70-300 is a Full Frame lens while the DA 55-300 is NOT. So you have an obsolescence proof lens once Pentax / Ricoh comes out with a full frame camera. The reason why I have avoided all DA lenses. b) The APO version of the Sigma 70-300 is better.

Pentaxians and Friends, never buy refurbished electronics. The defects for which it was sent back to the factory WILL RETURN at some point. Random failure with electronic equipment especially HANG UPS is often due to motherboard or component or software fault no matter what the manufacturer tells you. Hard to diagnose. Worst still the problem will not show up when you bring in your camera for repairs - leaves you frustrated.
Now the good stuff is that some of these problems are well documented on the net - just google. Looks pretty silly if you analyse some of the causes - battery grips, bad battery or an SD card, condensation, dirty contacts on the lens or body, buggy firmware, and many times owners themselves. Try a full reset of all the menus. Finally send it back if under warranty. Next time think twice if you buy stuff made in Thailand, Indonesia, Vietnam, Philipines, ... and Timbuktu.

Hello Pentaxians, technicalities apart, those of us coming from the romantic and beautiful era of 35mm film, have a hidden and burning desire to own a full frame DSLR. Here is my own experience. Circa 1978, holed up at the Edinburgh Railway Station due to a raging blizzard, I starting moving around with my Pentax K1000 SE. A guy with a Hasselblad walks up to me smiling. Points his camera to the beautiful stained glass dome and asks me to have a look at the ground glass. I was stunned at the beauty of that view his camera showed. I vowed to buy one. Alas never had that much money. My esteemed friends, a full frame DSLR has a magic of its own - nothing to do with snob value. And technically it [b]is[/b] superior too in every way - don't fool yourselves. Reason why I have set my mind on the medium format Pentax DSLR. Good souls, please help me with a donation!

Dodge69 Sir, I am surprised at a lot of comments on a "CHEAP" Tripod. And why should name brands - Velbon, Manfroto, Benro, blah blah be good only. Here is my US $ 22 Cherry - Made in Japan Tripod. Fits into my camera Backpack and pretty light. Takes the weight of my K20D with a 400 mm birding lens.
Oh ho, cant attach a photo here - please see my album as nanhi on the pentax forum (USA) or send me a mail at "nanhi at hotmail dot com" for the photo. Regards.

I am a "straight from the camera" person and believe a costly DSLR should output atleast a 90% match to the real life scene - IF camera settings were set wisely for RAW or RAW + JPEG. I would have shot ETTR, AWB Cloudy, ISO 400, invoked DR for the ominous clouds, and used exposure bracketing.
To get the best out of the JPEG, I would set Fn menu to Bright and boosted Saturation, Hue, Contrast and Sharpness - to mimic the velvia look. And then tried PP as a last resort.
Sometimes I believe my stand-by Panasonic P&S performs better and faster with its Scene mode!?

Many Pentaxian Users post photos in this esteemed Forum so that they can get constructive criticism, feedback on improvements and above all encouragement to improve their photography.
But comments like "LOVELY, GREAT, BEAUTIFUL, STUNNING ... blah, blah, etc"
do no good.
Pentaxian PROS, pseudo PROS and those of us with flashy DSLR's who think they have become PROS, make no contribution towards enhancing photography skills or techniques with such comments.

I've lived in Oman for (1 years and have currently settled in Bangalore, India. I have traveled all over the world and find India very safe. In fact I had my backpack stolen in Rome with my passport and K20D.
Revenue from sales of DSLRs in India = sales from all P&S cameras put together.
Just walk into Bangalore's Lalbagh, and you can see DSLRs galore, and 20% of them with 300 to 500 zooms.
I think one needs to take obvious precautions any where in the world - and an unobtrusive camera with a compact lens is a great idea.
Attached are some photos from the Pentaxian's Meet on 12 June 2011 at Lalbagh Bangalore (please copy & paste into your browser):-
http://www.pentaxforums.com/forums/members/nanhi-albums-pentaxian-meet-lalbagh-b...

Dear Smeggypants Sir (Smellypants Sir - friendly pun only w/o malice), appreciate your expertise as an electronics Engineer. My humble apologies, as I have used WD-40 on squeaky volume controls and other electronics for the last 18 years with good results. It is also inert to most consumer grade plastics. In fact I have observed on multimeter rotary switches that it acts as a surfactant and gunk remover. I am a Master Mechanic, a DIY Electronics buff (university topper in Electronics but chose Mech Engg) and retired last year as Advisor Nissan ME, North Africa and the CIS. I have helped a lot of people with repair of electronic gadgets, cameras, binoculars and lenses absolutely free.
Foam Cleaners are a good idea if it will not short circuit electronics.
Give it a try Alig Sir, if your camera is out of warranty.