Originally posted by fevbusch
These are really nice shots, Hattif. Make two columns one for each lens. List the benefits of each lens .Check off the column has the benefits you find are the best. Like: IQ, Bokeh, low light performance, ease of use, and whatever column gives you the best check the box for that lens. Winner = the lens with the most positive qualities. Freddy P.S. if one lens does something the other lens just can't do, then keep both lenses.
Thank you Freddy!
A very quick comparison looks like this:
IQ, bokeh, sharpness, low light performance: Sigma wins all, although the difference is not as huge as you would expect considering the price difference. The plastic wonder can play with the big boys!
Ease of use: here the Sigma at 665g is no match for the small and featherlight Pentax lens which is really a joy to use. Also, there is "fear-of-dropping" factor that comes into play. I don't have tons of money so I tend to be much more careful with an expensive lens, and because of that sometimes I miss some good shots.
Post processing: advantage goes to DA 35, I haven't been able to find a correction profile for Sigma to use in Lightroom. I could make my own but it will take some hours and work to make it properly and I'm lazy.
Autofocus: The Pentax lens does slightly better, but could be just my impression. Maybe the Sigma needs calibrated or maybe it's more difficult to nail the focus at fast apertures like f/1.4. Considering that I'm using it a lot at fast apertures, it has a higher chance to miss the focus I guess.
FF: Sigma is FF lens, who knows, maybe in the future Pentax will indeed release a FF camera.
Looks: Sometimes size does matter, I know it's stupid but you look more "pro" with the Sigma. My first model knew nothing about photography but she was concerned about the size of K5 + DA35. She got more confident when I started to use the Sigma.
I decided to keep both lenses. I do a lot of hiking and I'm always taking the 15mm Limited with me for landscapes, but during those hikes if I want to take a quick portrait of some friend, the DA35 makes a much better pair with the DA15 as they are both very small. Carrying the Sigma lens with me would hurt my backpack, not to mention chances of damaging it. But I also do a lot of pictures in places with bad low light conditions (pubs, bars etc.) and then I always take the Sigma, although the DA35 does very well wide open too. But Sigma is almost 2 stops faster.
There is the emotional factor also, I love my DA35 so I don't want to sell it