As the light levels drop and you have need of fast colour film they are, as we shall see, like hens teeth - a pretty rare thing - with very few choices available.
First of all we are talking of films of 800 ISO or faster. Second, perforce, we are are talking of colour negative films as there are no fast colour reversal films out there. Third we are talking of native fast films i.e. ones which have a fast box speed not slower speed films which have been exposed at a higher speed and then push processed.
So first up is Kodak Professional Portra 800. This is king of the high speed emulsions in every way with finer grain, higher sharpness, and saturated colour reproduction. Based on Kodak's Vision 2 movie film technology, it delivers superior underexposure latitude for less-than-perfect conditions, with the ability to push to 1600 when you need extra speed.
Lomo CN 800 film is comparable to Portra 800 but with more noticeable grain, exaggerated reds and greens, paler blues and less deep blacks. It is not intended to be pushed to higher speeds, 800 is its limit in my experience. It does have one big competitive advantage, price. But more of this later. It has one issue associated with it which is continuation of supply. It regularly goes out of stock on the Lomo shop website for several weeks at a time. Not good.
Then there is CineStill Xpro 800T which is a tungsten balanced 800 film made by stripping the Remjet anti-halation layer from Kodak's Vision 3 500T Motion Picture film so that it can be processed in standard C-41 chemistry and loading it into 35mm cassettes or indeed creating 120 rolls.
The result is a film that can be exposed anywhere from 200-1600 notwithstanding the nominal 800 ISO without losing highlight or shadow detail and can be pushed up to 3200. So what's the catch?
The catch is it is balanced for orange light at a temperature of 3200K so to use it in daylight you need to expose it at 500 ISO and use an 85B filter orange filter otherwise your pictures will have a blue tint.
The other catch is that "it exhibits a unique halation effect" i.e. a blurring or spreading of light around bright areas on a photographic image. In some images this is quite pleasant and in others it is pronounced and highly unpleasant.
For me, this makes 800T a film that can't be relied upon for general purpose use. Now Kodak used a lot of this Vision 3 technology when creating Portra 400 which may go a long way to explain its huge popularity, but I digress.
Thus we have a choice of exactly three fast colour negative films and that's it. So in terms of cost then in 35mm format, a roll of CineStill 800T sells for about £13, a roll of Lomo CN800 about £8.63 and roll of Portra 800 runs at about £12.50 (with a 10%+ price hike due in early 2021).
Whilst I was researching the latest film prices, I tripped over the above which is a Japanese import. This appears to to be good old Fuji Superia 800 X-tra without the X-tra if you know what I mean? Fuji 800 has been long discontinued here in the UK and round the world; it was last sold in Japan under the Venus brand and a remaining few of these have found their way to UK shores for the princely sum of, wait for it, £19.50 each - ouch! It is no longer listed by Fujifilm in Japan.
So where does this leave us? Well here is my take on all of this, but be aware this is, as always, a personal view so make up your own minds.
My own choice for the best quality, all rounder, do anything, use any time, go anywhere, always available, pushable to 1600 film is Kodak Porta 800. Everything else has a compromise of some sort associated with it.
At £19.50 a roll forget Fuji Superia Venus 800, it's the end the road for the old Superia 800 X-tra which was no where near the quality of Portra 800, so unless you want to try one out of curiosity whilst you still can, then save yourself the money.
CineStill 800T is great night-time film, with outstanding exposure flexibility. It can be used in daylight with 85B filters on your lenses but this is a big faff. Plus the film exhibits halation which is a love hate thing - personally in night-time pictures I think this is OK but in daytime shots absolutely not. - I still prefer Portra 800 for both day and night.
This brings us to Lomo CN800. This is a nice film especially for night-time pictures where its over saturated reds and greens add to the mood. For the price, it is remarkably good, though the cost has been creeping up regularly as it is restocked after the long gaps when it is missing from the shelves. I still much prefer Portra 800 but the price differential makes CN800 very tempting for use when snapping away just for fun.
Thus for now Kodak Portra 800 remains my first choice for high speed film though after the 10-20% price rise announced by Alaris for next year comes into force I might change my mind, but I doubt it, it's just so good.