I have short listed Nikon CoolPix S9100 and Sony DSC-HX7V. I am really confused out of these two which one should I buy. I am not a professional photographer who understands the terminologies of photography, but yes, I am the type who loves clicking and making movies. I also travel a lot. Please do suggest in case you feel that I should consider some other model of some other brand. As of now, I am using Olympus (which I purchased 6 years back) which is just a 6mp camera. Photos taken at night are really bad. This is the main reason I am looking for other options.
I own the Canon Powershot S95, and it has a fast f/2.0 lens when used at its widest setting. I have some amazing quality photos taken at night or in low indoor light with it.
That said, the Auto Focus can be slow and hunt in the low light. So if you are in a situation with low contrast it can be frustrating to use as it's focussing. However when it finds it, it's great. Also the built in flash (for close ups, party photos etc) helps a lot.
It also has full DSLR-style P/A/S/M modes so you can tripod mount it in the dark and have full control over exposure. ISO noise is well controlled.
In summary, it gives really sharp nice pics, in low light (AF issues aside).
It has been replaced now by the Powershot S100, perhaps that is better with the AF?
You need to let more light in. Quick answer: look for lower f-stop (smaller number), slower shutter speed and higher iso capability. However photos at night with a compact camera may tend to disappoint regardless.
If your camera can do long exposures (1/2 second or longer) try using a compact tripod or Gorillapod type support. Much cheaper than a new camera, will force you to plan shots (at the cost of spontaneity) and if it doesn't meet your needs you have a tripod for the next camera.
You should also consider one of the new Nikon 1 camera series. The J1 is pretty close in size and weight to the S9100. Going with a Nikon 1 camera would be more expensive but it will address your desire to have improved low light performance. The sensor size in the J1 is a lot bigger than in a compact and that tends to provide better low light performance.
I don't own one of these guys but the reading I have done seems to indicate that it will out perform any compact camera. I would echo what epo said above about needing support for long exposures you simply cannot hand hold even small cameras for 1/2 a second. Heck most people will probably not be happy with the images from hand holding with shutters speeds a lot faster than that.
An important question to answer is how much better low light capability you want. A small sensor camera, such as you have and are considering will always have worse quality than a larger-sensor camera.
I'm sure either of the cameras you're considering would offer a notable improvement over a 6-year-old camera.
If you want something even better, you really need to step up to a camera with a larger sensor, such as the Nikon J1 or V1 or a micro 4/3 camera such as something from Panasonic or Olympus. The image quality difference between these cameras and the smaller compacts is very significant.
what about Nikon Coolpix P300? It has very good 24-100mm (equivalent) f/1.8-4.9 lens with optical stabilization and 12 megapixel BSI (back side illuminated) CMOS sensor. Both features are very good in low light conditions. Recommend to go here and compare the picture outputs for possible candidates for various ISO settings and picture details.
P300 has both automatic mode and advanced controls and priority modes and it can also shoot HD video.
PS: I have this camera as second one (first is a DSLR) and it is really good.
You should look at these offerings:
Canon S100 Fujifilm X10, or if budget is not a problem, Fujifilm X100
The above provide lenses that are able to absorb light at f/2.0 when you zoom out for landscape at night (but please don't zoom in at night for the canon as its sensitivity to light drops when you do so).
I tend toward the Fujifilm X10 is because its ISO performance is much better. In other words, the quality you will see when shooting at night will be better, the picture tends to be sharper with more colour and contrast. In addition, it has picture styles from vivid to portrait to standard that are some of the best now on the market.
Here's a review that compares the Nikon 9100 with the Sony HX9V:
If you truly want the current king of compact low light, look at the Fuji X100. I have one, and I'm happy with the quality of photos I get at ISO 3200. The Fuji X100 beats all other compacts and many large dSLRs for image quality at high ISO.