Depends on your technique mostly. I find 1/30th just fine on a 35mm range finder, but on my 6x6 range finder, I get shaky images. Obviously try to keep speeds as high as you can, 1/60 or faster. Also, try steadying techniques like pushing camera against your face a bit for steadiness, squeeze the shutter button, rather than push/jab. Also try even regulating your breathing.