People talk about Kodak Portra having a huge latitude. They haven't tried Fuji's Natura!
Kaoshiung, Taiwan - Natura 1600 at 100 ISO
I used to shoot Porta a lot when it was still reasonable to buy in Japan. The price has almost doubled over the past year. I shot Portra 400 from 100 iso - 1600 iso and developed normally. I never liked it at 100 or 200 ISO. It turns yellow and I didn't like the saturation. 1600 is possible but it doesn't look good anymore. I found the usable range to be around 320 - 640 iso. Anything outside that is really not as amazing as they advertise it to be.
Fuji's Natura 1600 on the other hand is a real gem. This film seems to only be available in Japan. I've heard of Superia 1600 being sold in Europe and the U.S. but I am not sure that's exactly the same emulsion. Here in Tokyo it's available at every camera store and even after all the price increases it still sells for 850 yen a roll, which is quite reasonable compared to Portra 400 which sells for 6700 yen a 5-pack.
Natura 1600 is one of my favorite films. It's perfect for any weather, any time of the year or day. I shoot it from 50 ISO to 1600 ISO and the colors just look right no matter how much you stretch it. Some people complain about it being grainy. I've personally never been allergic to grain, but honestly, especially when overexposed, this film has very little grain. It's the perfect film to take with you on vacations. I just took 10 rolls to Taiwan with me. I knew I wanted to shot indoors, during the day and at night. Natura 1600 is the perfect film for that.
Night time at 1600 ISO
In bright daylight at 50 or 100 ISO
Rainy day at night with city lights at 1600 ISO
In bright daylight at 50 ISO - 5 stops over exposed!
City lights at night - again amazing colors at 1600 ISO