Shutter speed relative to focal length on DSLR

[bluesinlondon]

OK, so as a rule of thumb I need to be using a shutter speed at least equivalent to the focal length...

However, I'm using a camera with a smaller-than-full-frame sensor (Canon 20D) which means I multiply lens focal lengths by 1.6

For example... "200mm" is actually 320mm...

... does this mean my shutter speed should be 1/200th or 1/320th?

Feels like this is maybe a stupid question but...

... and I've found conflicting things on t'internet.

Thanks

[postcardcv]

Feels like this is maybe a stupid question but...

... and I've found conflicting things on t'internet.

and you'll get conflicting arguments on here too, there was a thread about it recently I'll dig out the link...

Personally I'd say that you ignore the crop factor a 200mm lens requires the same shutter speed for a steady shot regardless of the size of the sensor.

here's the recent thread - http://www.birdforum.net/showthread.php?t=135391

and an older one on the subject - http://www.birdforum.net/showthread.php?t=50295 though I'm not sure that they'll make it any clearer!

[hollis_f]

Technically it is correct that the 1.6x crop factor should be taken into consideration. However, it's a bit more complicated than that....

The 1/FL 'rule' for shutter speed is by no means a rule. The person to person variation in how stable they are when shooting is huge. I can get reasonable results at much slower speeds than 1/FL - even on a 1.6 crop camera. My friend has to go up to around three times faster than that - because of slight tremor.

So each person should try to estimate their own limits - rather than following a 'rule' that almost certainly doesn't apply to them, personally. So Pete's probably right to ignore the rule - as the normal variation is much more than 1.6 times.

[Roy C]

I am not that confident with the shutter speed = focal length rule. It may be ok with wide to medium focal lengths but with longer focal lengths it goes out the window IMO. As an example I can hand hold my 400/5.6 and get sharp shots at around 1/400 - 1/500 sec but if I add a 1.4tc I struggle to get sharp shots at 1/1000 or even more (which is why I always use support when shooting at 560mm). Also how many people would hand hold a 500/4 or 600/4 with IS turned off and speeds of 1/500 - 1/600, with these bigger lenses weight must play a part. Just my 2p's worth.

[RAH]

I think you SHOULD take the crop factor into consideration. Regardless of whether it is real magnification or just a crop (we could argue that forever), it is harder to keep a 300mm lens mounted on a 1.5 camera steady than it is if it is mounted on a full-frame camera, in my experience. Besides, it is just a rule of thumb and is pretty flexible, and I think that anything that warns you about being too confident about handholding is a good thing. Better to err on the side of caution.

[Duke Leto]

in the field you may not get a choice, where ever possible I try and get the best shutter speed for the required aperture and iso, sometimes that may be less than what the "rule" stipulates sometimes more, for a record shot shoot at what ever you can get away with, if you can keep it steady enough, to produce quality prints you need a sharp image. You don't indicate how you are mounting the lens as this will also play a part.