Do I need prime lens for lowlight shooting if I have a tamron 17-50mm f/2.8?

I was thinking of getting the Nikon 50mm 1.8 and the 35mm 1.8 for lowlight shooting to compliment with my tamron lens. But would that be wasting money since my tamron is pretty fast already. Plus I have a Nikon sb-600 speedlight with my Nikon D90.

Only you can answer this question.

Set your Tamron to f/2.8, and see if that gives you the low light performance you need. If not, get one of the faster primes.

When considering the purchase of new equipment, see if your current kit will work. If not, buy equipment which will improve on the problem you currently have with your existing equipment.

Huywee, your Tamron is fast for a zoom but it is slow for a prime. As to if you prefer wider aperture and fully body movement over a more limited aperture and the ability to zoom in and out is completely a personal preference.

Personally, I'm happy to forgo the ability to zoom for an extra stop or two of light. An extra stop or two may not sound like much but it can be the difference between having to bump up my ISO (and get grain/noise) or slow my shutter (and get motion blur.)

I prefer the discipline and different way one has to shoot with a prime lens. It makes me move around with more creativity than when I have a zoom, which encourages me to stand in one place and zoom in and out instead of explore other angles.

Fast lenses not only let more light in the camera but they also can create really compelling bokeh that is simply impossible with a slower lens.

I also don't use a flash at all so for me, it's all about high speed film and high speed lenses.

At the end of the day, what matters is your shooting techniques and preferences. If the comments I've made about why I prefer fast primes interest you in changing/expanding your techniques, then you should certainly try one or a couple of these lenses. If you are content with your Tamron and get great photos out of it, you can stop there and just perfect your current method. Or you can choose to explore more and expand your abilities. There's nothing wrong either way.

I don't think you'd be wasting money even if you decided you didn't like to use fast primes because then you would know and could happily return to your zoom.

As far as the two lenses in question, in particular, both are excellent and will probably produce pretty stunning images (particularly if you have never used a fast prime before.) Shoot the 50/1.8 wide open and close to your subject and it'll take your photography in a whole new direction.

I guess that despite my saying you're fine to buy or not to buy, I'm really encouraging you to buy!

Have fun!

The Nikon AF-S 50mm f1.4G is 2 full stops faster than your f2.8 zoom. Suppose you're shooting indoors with available light at f2.8 and need ISO 1600 to get a shutter speed fast enough to avoid blur caused by subject motion. Change to the 50mm f1.4G and you can use ISO 400 and get the same shutter speed.

Call me old-fashioned but the plastic lens mount on the 50mm f1.8 is a real turn-off to me. It might last for decades but I still prefer good old metal for a lens mount.

If it were my money it would be spent on the 50mm f1.4G lens.