Many photographers that are shooting for the micros often are concerned with relation to situations where there is low light and a high ISO is required. I've heard artists ask if they should just skip the image altogether and are frustrated with relation to low light situations. Here are the options that I've used to help me get around the situation:
1) Use a tripod and a lower shutter speed at 100 ISO.
2) Shoot at a high ISO and bracket up (over-expose) by about 2 stops, then bring the exposure down when processing the image. You will get less noise this way.
3) Shoot at high ISO, then process in Neat Image. You'll be surprised sometimes what you can save. If that doesn't work, reduce the size of the image to hide the noise (a big option at the micros).
4) Process for noise using the following actions in Photoshop:
a) Open Image
b) Image> Mode> LAB Colour
c) Channels palette-select channel “a”
d) Filter> noise> Median 3 pxls-
e) Select channel “b”
f) Filter> noise> Median 3 pxls
g) Select channel “lightness”
h) Filter> Noise> Despeckle
i) Image> Mode> RGB Colour
then, sharpen the image using the following actions:
In PS go to Image>mode>Lab mode and convert your RGB image to lab mode. Then in your channels palette click the lightness channel and the image will become black and white. You can then apply a small amount of USM (unsharp mask) to the image.
The guidelines that a popular RM site allow for this are: Amount 0-100%, Radius 1-2 pixels, Threshold 0-4 levels.
Don't ever try to sharpen a soft image taken in low light by using unsharp mask or other conventional sharpening techniques straight on the image. It won't work - trust me and believe me. The results will be bringing the attention to noise and distorted pixelsI have a couple of images in my portfolio here that were shot hand held at 3200 ISO. An example is this image
Shot at 3200 ISO with a 50mm f/1.8 handheld at f/4. This was taken at a telecommunication network switch - flash was not allowed in the room (it disrupts telecommunication traffic) and bright lighting was not allowed. There wasn't enough room between the network racks to set up a tripod and I didn't own a monopod at the time.
It is possible and it is worth refining your low light techniques especially if the image is unique! Take a chance!