[leonardotmnt]

I have a K-3 with a 50mm 1.8, 18-135, and 55-300 WR right now. This covers most of the focal ranges I need but I'd like to start getting higher quality lenses. I was thinking of the Sigma 17-50 2.8 to use for landscapes and portraits but lately I've also though about the 50-135 2.8 for portraits. The reason I thought of the 50-135 was that it seems some people like that range better for portraits. I know they're completely different lenses with different uses but eventually I'd like to cover both spectrums with quality lenses. I've thought about eventually starting a side gig and possibly doing some family portraits and the landscapes would be for my own personal photos. Which one would probably be more useful for the time being given what I have already? Thanks!

[hcc]

You have two zoom and one prime lenses. Pentax is renown for its very high quality prime lenses with focal lengths below 100mm. Consider very seriously to invest in a few very good primes.

I have a K-3 and I would recommend very strongly the FA77mm f1.6 Ltd for portrait. It was awarded PF best lens last year, for a good reason. And it was called the vest AF prime lens that you can buy across all brands (incl. CZ, VL, Leica.....): http://www.luminous-landscape.com/columns/sm-02-05-02.shtml. For landscape, a 17-50mm zoom would be good option, or you can choose some high quality primes: DA15mm Ltd, FA31mm f1.8 Ltd, DA 21mm Ltd. I have the DA15 and FA31 and they work superbly on the K-3.

Food for thought, coming from someone who love his prime lenses.....

[lsimpkins]

I own the Sigma 17-50 2.8 and use it more than any of my other lenses. That being said, its IQ seems weakest around 50mm where you would want to be using it for portraits. And 50mm may be OK for full body portraits, but I think longer would be better for head and shoulder shots. I like wide angle for landscapes. While 17mm usually gets the job done, I also really love the images out of my Pentax 12-24.

[C_Jones]

I have a Pentax 16-85 that I use with my K-3II. It does really well.

[eminker]

FWIW, I own the Sigma 17-50mm F2.8 as well as Pentax 50-135mm F2.8. Sigma IQ is OK but nothing mind blowing. At the 50mm end, it hunts for focus even in decent light. The Pentax 50-135mm is a superb lens (definitely a favorite) but IQ is sharper and this one is definitely better for portraits. But since you already have a few zooms, you may want to consider going Prime . Pentax FA 77 mm is a great portrait lens choice and for architecture/landscapes, I go with Sigma 10-20mm F3.5 but you have a nice choice of prime Pentax UWs (15, 21 mm) available as well. You can't go wrong with the FA 77m or the FA 31mm.

[RoccoStiglitz]

I know they are big and heavy and FF and expensive but the DFA zooms are spectacular lenses. Mine never cease to amaze when it comes to clarity and how they handle (worth it for the snappy accurate AF alone in some cases). IMO they are a step up from any of the older lenses. And who knows maybe someday you'll get an itch for a FF body. Maybe rent a 24-70? Seems like a good focal range for portraits on APS-C.

I also don't think you could go wrong with any of the primes from 43mm and up.

[aslyfox]

I know they are big and heavy and FF and expensive but the DFA zooms are spectacular lenses. . . . Maybe rent a 24-70? Seems like a good focal range for portraits on APS-C.

I also don't think you could go wrong with any of the primes from 43mm and up.

I second the idea of renting some lenses both primes and zoom, and doing your own evaluation.

I have had good luck with LensRental.com but they are not the only ones around

if you rent be sure to get the best protection program they offer in case of trouble.

take a look and give the lenses a try.

be aware lensrental.com may offer to sell you the lens you rent and take the rental fee off the purchase price.

[Scorpio71GR]

So I have or had all the lenses you mentioned. The Sigma 17-50 is a very good option and very affordable right now. Sigma colors tend to be a bit cooler than Pentax with a little less contrast, but that is all preference. The DA*50-135 is one my sharpest lenses. It is compact enough to shoot hand held all day without tiring. However the SDM autofocus is slow, there is no denying that. It tends to hunt quite a bit too. Since getting a Tamron 70-200 I have essentially switched to that, plus it works on my K-1. The Tamron is about the best FF 70-200 you can get for the money. Some have mentioned the FA77 which is an outstanding lens, but very pricey. You can get a DA70 for a lot cheaper. Actually you could get a DA40 and a DA70 for less than the FA77. Another option is the DA*55 1.4. I thought the DA*55 was good on my K3, but it is simply amazing on the K-1. My advice would be too look into either the DA*50-135 or if you can find one a Sigma 50-150.The Tamron is great, but most likely you will find the 70mm end on your K3 to be too narrow at times. Keep in mind of the SDM issues with a DA*50-135. If you buy a used one, and there are enough them out there, be careful. Also be prepared and accept the fact that you may have to convert it to screwdrive at some point if it has not already been done. Other than the autofocus issues, it truly is a gem of a lens. After that look into a lanscape lens with money made from portraits. I feel a 17-50 would be too limiting for being your only portrait lens. For the time being use your 18-135 for anything wider. Just keep people out of the borders on the 18-135, that is were it is the weakest. In the center it does a pretty good job.

[twilhelm]

You've gotten some great advice so far. I started with a set up very similar to yours, I had the K10 + 18-55 kit, M 50 f/1.7 and 55-300 (original version).
Since I had contracted to do paid portrait work, I wanted a great portrait lens and bought the FA 77. I shot a lot of portraits, in studio and out with that lens and it never disappointed me. The next lenses I purchased were Sigma, 28-105 and 24-135 (I think it was 135 as I've sold it since). They were good lenses and very sharp, but lacked the contrast and colors I was getting from my Pentax lenses. I then purchased the DA 17-70 which became my go-to for events. Many have complained about the SDM hunting with the lens, and at 70mm it will from time to time on me. But I worked with it and found a work around. I used that lens for several years for many paid events.
I now have the DA 20-40 and DA 50-135. A little pricey, but I feel they were well worth the extra money, especially if I'm getting paid for my work. I have a good SDM copy of the 50-135, but as already stated, it has been known to have issues. I feel the lens is so good, I would pay to have the SDM repaired or would likely convert to a screw drive myself.

The 55-300 is a great lens. But I also feel you should rent a lens or two, especially if you don't have money to throw around at a bunch of lenses. I have MANY prime lenses which are all stellar and render in their own unique way. The 35 f/2.4 is another good prime to have. I didn't think I would like it as much as I have and I use it frequently as a walk around lens.

Good luck, and I'm sure there will be a lot more great advice to follow.

[skierd]

The 50-135 is amazing for portraits and head shots, of course it was built for it. If my sdm dies I'm definitely going to have it repaired.

Then again, some of my favorite photos of my daughter were taken by my 20-40 limited.

Those are my go-to kit.

[clackers]

Great combo, the Sigma 17-50 and the Pentax DA*50-135. The pictures are fantastic.

[grispie]

I was thinking of the Sigma 17-50 2.8 to use for landscapes

Personally i wouldn't overlap too much with your 18-135. For landscape i'd think more in terms of da15 or da12-24 or similar 3rd party. Quite different from 18mm..

For portraits i'm pretty happy with my da70. I always wondered about the da50 135 though. From reading the various posts here, seems it has an x factor.

As far as primes go, the fa31 is pretty much glued to my K3..
choices ;-)

[Angel Perez]

I think you are eventually going to by both. I have a Tamron 70-200 and a Sigma 17-50. I really like both lenses and I hope to by a 50-135 as a back up. If your budget allows rent them and then make a choice. My financial strategy would be to by the 50-135 since that is the lens you will be using most right now for your paid side gigs. Use the profits of this to pay for your landscape passion. Actually, I use the Sigma as my go to lens for events. In a tight space it will save you. I also use it for 3/4 or full length shots so that I am not shooting the model from sniper range.

Good luck

[Elar]

I had Sigma 17-50 f2.8 but it was probably very bad copy. It was sharp only at 50mm f4 and above. At f2.8 was almost unusable. I also tried to finetune autofocus but if I got more sharper results at 50mm then 24-35mm range it went even worse. 17mm was very soft all the time, so it cannot be used for landscapes. So if you go for Sigma, you'll have to test the lens first if it is a good copy or not.
Pentax 50...135 is better option.

[aslyfox]

If I recall correctly

way back when [ in the 35 mm slr film days ] I thought I read that lenses were classified by focal length ( by whom I have no idea ) as:

shorter than 50 mm was " wide angle " and the shorter it was the more extreme 50 vs 35 vs 20 vs 10 etc

50 mm was the " normal " lens ( it mimics the viewing angle of the human eye if I recall correctly )

longer than 50 was " telephoto " and the longer it was the more extreme 50 vs. 100 vs 300 vs 500 etc

and a " short " telephoto ( up to 100 mm or so ) was chosen for portraits

I believe that was all based on the " viewing angles "

and now with digital ( except for FF of course since such cameras have a sensor mimicking the size of the 35 mm film negative ) you have to figure the crop factor

so with our Pentax non FF cameras, a 50 mm lens becomes a " short telephoto " under such a classification system