Dose the term "third party lens“ make your skin crawl? When I think of them, images of bad pawn shop bargens pop to mind. I knew a guy that bought a push pull zoom that would always change it's zoom depending on the angle you held the camera. Does that mean all third party lenses are junk? Of course not! Some of the best lenses out there are from third parties.
Most lenses from Zeiss, and the tilt & shift offerings from Schneider will be exceptional choices. Priced around four grand the Zeiss 55MM Otus represents more of a speciality lens, than a simple upgrade from the Canon/Nikon 50. There is an amazing and affordable kit from Zeiss priced around six grand. This kit offers 5 prime lenses cover 21 - 85 MM and apertures of 2.8 or faster! The whole kit comes packaged in a customized Pelican case, Whats the catch? These lenses are manual focus.
Is there an affordable alternative to on brand lenses that rival them? In my humble opinion Sigma is that option. I have been using Sigma lenses exclusively for over 15 years, and not one time has anyone ever looked at my photos and said anything bad about then based on the quality of the lens. Not all Sigma lenses are created equal of course, so you had to look at the specific models. My Sigma 28-70 F2.8 is getting pretty old, and is need of some calibration, but for the past decade it's been my workhorse. I Have been impressed with what this lens is capable of, and it was nearly half the price of the comparable Nikon lens! The other essential lens in my bag is the Sigma 70-200 F2.8. This is my portrait lens, because its sweet creamy bokeh is so easy and predictable. I know it's not the best focal length for portraits, and I have had my frustrations with it. Overall these 2 Sigma lenses represent a good portion of my basic kit.
Not to long ago Sigma changed its philosophy on it's lens line-up, and is noe working on their " New Global Vision " series lenses. These so far come in three flavors Art (8), Contemporary(2), and Sport(1). These lenses like all Sigma units are produced in house in Japan. All you have to do is read any kind of photo related press, and you are likely to read about the new benchmark standards in quality these lenses have been setting. The newer lenses have increased a small amount in price but appears to be well worth it terms of return on investment. The one caveat to be aware of is that these lenses will not sell for as much on the used market, but then again you shouldn't want to be parting with them!
I am personally excited to see this range mature in a full lineup, I already have my eye on a few of them, and will definitely be replacing my 28-70 F2.8 as soon as an suitable Art series is introduced. I am also excited about the usb dock that lets you adjust and calibrate the lenses without needed to send them off for days or weeks. Bottom line is be sure to check out the new Sigma line up if your in the market for new lenses, remember that they will outlast the bodies you use them on! Oh yeah if your into the techie part of lens comparison don't forget to check out what DxOMark has to say about them.