I've been seeing a lot of "Please help me choose a lens" threads lately, and I can understand it. It takes a lot of time and effort to read all the reviews, learn MTF charts, read more reviews from other sites, read marketing literature and then figure out what to buy in your budget.
What makes me an expert? Probably nothing, but what I have done is owned many of the lenses or it's contemporaries over the last 10 years that I have been in Digital Photography. I have logged hundreds, possibly thousands of hours reading reviews and mtf charts for these lenses, and I have shot 10's of thousands of pics with these lenses. I am not a pro, but I consider myself an advanced amateur. I do not have an unlimited budget, but this is nearly a self financing hobby, so I have justified expenses accordingly.
Below is a summary of what I would buy/have bought/currently use (and would consider worthy of a Pro's kit) and I'm offering it as a starting point for all the questions of "What lens should I buy.." with the caveat that I am a zoom shooter (gasp of horror) because of my style and locations. So if IQ is your first priority, followed by versatility and price here's your choices:
Sigma 10-20 f4-5.6 - Yes it's 5.6 but this is a landscape lens and if you are shooting below f8 you are doing something wrong.
Tamron 17-50 f2.8 - I have owned the sigma 17-70, sigma 17-50, sigma 20-40, pentax fa20-35, da15, da40, fa35 all in this focal length. The Tamron wins for flare control + sharpness + diffraction control + versatility + price. This is really where my zoom bias comes into play. Honorable Mention goes to the Sigma 18-35, but it's an $800 lens and I'm not sure one can get 2-3x as much quality out of it.
Any 50 Macro - Honestly you are literally splitting hairs over the various AF 50 macros out there.
Sigma 50-150 f2.8 - I know it's not fair to include a discontinued lens, but I have owned the DA*50-135 and this lens blows it away in focusing and reliability. IQ is equal. Sorry Pentax but until you put a DC motor in the 50-135, it's not even a contest. Instead of the 50-135 I'd even recommend the next lens on this list.
Tamron 70-200 f2.8 - Only lens in this range available for Pentax shooters since Sigma is discontinued, and I much preferred Sigma, but the Tamron is not bad. It's not in my bag, but would be if I needed it. It beats out the 60-250 because of the extra stop and I just don't trust SDM.
DA*300 f4 - The only choice for Pentax shooters to reach Pro IQ AND stay around 1k. Sorry DA55-300, you can't play in this sandbox. You're a great value but you are slow and slower and your IQ is a step above kit lens, but not in the same league as ANY of the lenses mentioned here in your focal length. I'm not going to include legacy or discontinued glass, because there is no telling what would be available on the market and when. Besides, if you have your heart set on an FA*300 f4.5 then you don't need my recommendations anyway.
For 400mm, buy a Pentax TC and mount it to your DA*300. No other way to get pro IQ with a pentax. the sigma 120-400 is basically equal to the DA55-300 in terms of IQ. Good but not what I would consider awesome. The Bigma 50-500 and Little Bigma 150-500 are better than the 120-400 but still not quite there. For under 2k though, they are really your only options to get to 500mm. Which leads to....
500mm - There are 2 Pro IQ lenses out there- The Sigma 500 f4.5 and Pentax 560 f5.6. Both cost around 5k, both are amazing lenses. I'd be happy with either after I get my inheritance from a long lost rich relative.
There you have it. A 5-6 Lens kit from 10mm to 500mm that will go anywhere and have you covered from landscapes to critters. Let the debate begin...
Last edited by nomadkng; 11-26-2014 at 01:24 PM.