The formula or the rule of thumb is: 1/(focal length x crop factor) s

For example, 50mm on 350D or on any 1.6 crop factor multiplier sensor:

1/(50 x 1.6) = 1/80 s

Means, the slowest allowable shutter speed is 1/80s. Note the word allowable, means you still can go below that, with a price though. For full frame DSLR like Canon 1D series or newly introduced Nikon D3, You don’t have to calculate as the minimum allowable shutter speed will always be the focal length of the lenses. Hence, the formula will always be 1/(focal length x1). The only catch is that all full-frame DSLR is cost arms and legs. You guy should already know what’s your camera crop factor is.

When shooting in low light condition, without any powerful flashgun, in fact i don’t have any :-(, and no fast lenses as well, I always choose sharpness over brightness. With the help of Photoshop, we still can recover the brightness, as long as the picture is not too dark or burnt out. Boosting the ISO level also help, but most entry level DSLR tend to produce lots of noise in high ISO.

The picture below taken with 70mm f4.0 1/200s, above the minimum allowable shutter speed of 1/200 s. The result, a bit dark image due to low light condition. But with very minimal touch up using photshop software, we can achieve acceptable image.

The following picture adjusted just with: 1- ctrl+j (duplicate layer), 2- change blending option to screen. That’s all. You can adjust more using curve, level, brightness and so on, but this just to demonstrate that how easy it is to do it. You can achieve better result with further adjustment.

The following image: 70mm f4.0 1/25 s, Clearly the shutter speed way is below the allowable shutter speed, which is 1/112 s. And the result, as expected blurry image. This kind of image, not matter how advance CS3 is, will still be blur or produced a very not original looking image.

Footnote, I’m just sharing what I know and the information shared here might not be correct. So, please correct me if I’m wrong okeh… And, I’m considering to get 50mm 1.8 prime lens. Should I? yes no yes no yes no yes no yes no yes no…….. zzzzZZ

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