[schnitzer79]

usually a prime means the best quality and relatively light weight but sometimes it can be restricting indoors (i.e. stage photography, concerts etc). There are times when you cant really move with your feet so a zoom would be a good idea. I was in the same situation where I only had my 18-135 and even though my shots were sharp, there were times where I had to use 6400 ISO. So I bought the sigma 24-70 f2.8. it might be a beast (in bulk and weight) but it is tack sharp wide open, and focus is super fast and spot on every single time. the 24-60 is much lighter so thats a very good option in my opinion. if 50mm is the max you need, then id suggest a 17-50 f2.8, either a sigma or tamron.

[TER-OR]

Some diffusers are really useful for indoor bounce flash, too. Using that I found the DA 16-45 is a nice indoor lens.
Another diffuser worth considering is the Fong Puffer for the onboard flash, it's pretty good but you do need to protect it, the way it sits is a bit precarious.

I do have a Sigma 28mm f1.8 which is more useful at f1.8 than I would have expected.

[ChristianRock]

My two cents.

Just get the DA 35 2.4. I have it for that purpose - low light family photos - and it turned out to be our walkaround lens outdoors as well.

Sometimes I use it with flash, sometimes just with natural light. Natural light pictures have more "mood" while bounced flash pictures are more technically perfect. I can also use one of my auto-thyristor flashes at 1/180 when the light is good, just to use it as a fill in flash. My Sunpak flash is perfect for this because its sensor underexposes - so it's actually perfect for just filling in shadows. I think you can buy these for 20 bucks - mine came free with my 12 dollar P30T camera

So the DA 35 2.4 will give you all this flexibility, and it's not expensive at all.

But here's the most important thing. It's not important just to be able to take pictures in low light, but how these pictures come out. The DA 35 2.4 isn't only sharp edge-to-edge wide open. It's also got something very cool going on when the light is dim. I can't really explain it, but this lens, that a lot of people consider a bit "flat" and even "boring" - really comes to life when the natural light is fading. It brings up the colors and contrast in a beautiful way, and a way no other lens that I own can. The images come out beautiful and often I hardly have to do any PP other than just adjust levels.

It excels in low light. I'd get one if I were you. Later you might decide to upgrade it to something like an FA 31 or Sigma 30 1.4 ART, but you'll know you'll be in the law of diminishing returns by then.

[Merts]

An update for anyone who is interested.

I bought a diffuser for the pop-up flash, which produces more natural looking photos than I get using the naked flash. I'm also using my Sun Auto-thyristor, generally bouncing it off the roof.
For photos at family functions etc, either of these works very well with the DA 18-135.

With the money I saved by not buying another lens, I bought another lens. (A Tamron 90mm f2.8 macro). Oh, and a 100 LED ring light/flash, and an auto focus capable Kenko 2x teleconverter......

I think I might still buy the DA 35 2.4 for myself for Christmas. (and/or the Sigma 18-35 1.8).

[ChristianRock]

An update for anyone who is interested.

I bought a diffuser for the pop-up flash, which produces more natural looking photos than I get using the naked flash. I'm also using my Sun Auto-thyristor, generally bouncing it off the roof.
For photos at family functions etc, either of these works very well with the DA 18-135.

With the money I saved by not buying another lens, I bought another lens. (A Tamron 90mm f2.8 macro). Oh, and a 100 LED ring light/flash, and an auto focus capable Kenko 2x teleconverter......

I think I might still buy the DA 35 2.4 for myself for Christmas. (and/or the Sigma 18-35 1.8).

That's the spirit!

[nanhi]

My home in Bangalore is a modest 2-bedroom one with a pretty long living room but just 13 ft at its broadest. Since the window faces the broader 13 ft side and the sofas are kept facing the window against the wall, most family photos are taken on or around the sofa.
With an APS-C Camera the best lenses to use are the 18 to 28 mm wide angles like the Tamron 17-50 f2.8 or the Tamron 28-75 f2.8. The ceiling height is 10 ft and painted bright white. On bright sunny days I do not need flash as the windows are very large. On dull days I use an external flash bounced from the ceiling. Never ever had exposure problems or go below ISO 400 with the K-5 or K-5 IIs.
I have the FA 28 f2.8 AL lens but I prefer the zooms for tighter framing. On just one occasion - a large prayer group - I used the Sigma 10-20 f4-5.6 with excellent results - both stills and video. Have attached a family photo taken recently. The only person missing is my son-in-law.
Regards.
nanhi
camp: San Mateo, CA.