crop factor and shutter speed

[gregA]

hi all

question when people say that shutter speed should be the reciprocal of the length of the lens ie 250mm lens needs 1/250th shutter speed as a guide do you need to also add the dx crop factor ie a 300mm lens x 1.5 becomes 450mm as such needs 1450th sec shutter speed.
sorry its a bit long winded but hope u get what i mean
thanks gregA

[marvin]

hi

i'm not sure why, given that the distance between the front element and sensor is the same, but from everything i've read people do take the crop factor into account and adjust shutter speeds accordingly.

cheers
tim

[slimrbp]

I have also heard people using the crop factor when using the 1 over focal length guideline I have never understood why though.
The physical focal length of the lens doesn't change so I would have the thought the same rules would apply regardless of the camera the lens is on.

It's only a guide anyway personally I would just go out with your lens and see what shutter speeds you can comfortably handhold your lens at and get good results as everyone is different.

[squishy]

Since you're getting in effect a crop of the actual focal length, any minor shake will be more visible than on a full frame camera.

So I generally would take it into account.

[johnf3f]

Originally Posted by squishy

Since you're getting in effect a crop of the actual focal length, any minor shake will be more visible than on a full frame camera.

So I generally would take it into account.

My somewhat illogical brain tells me that the effect of the camera shake will be the same as the actual (not effective) focal length is the same. However, logically(?) a movement of a given angle on an FF sensor will be 1.6 (1.5,1.3,2) times as much on a cropped sensor so I take it into account.
I use a 1.3 (Aps H) camera and all of my lenses above 100mm have IS so I don't get too worried about it, though I do bear it in mind.

[glsammy]

My brain can't deal with all this so I just use a monopod and hope!

[wizzo]

Originally Posted by glsammy

My brain can't deal with all this so I just use a monopod and hope!

I'm so relieved it's not just me.....PHEW

[Geoff F]

And, so far, nobody has mentioned the effect of 'wind rock' on large lenses.

[JeffH]

Originally Posted by slimrbp

......It's only a guide anyway personally I would just go out with your lens and see what shutter speeds you can comfortably handhold your lens at and get good results as everyone is different.

I agree with Richard - don't get too bogged down in the so-called 'rules' of photography

Jeff
(Schedule 1 Licence holder for Kingfishers, Barn Owls and Avocets)