Crop sensor vs ff sensor calculating handheld shutter speed

OK I have learned that crop cameras do not give you a longer focal length (which was what I was first taught here on POTN:lol regarding glass but will only change the angle of view, making it more narrow. A 24-70mm lens is still a 24-70mm lens focal length but will act as a 38.4-112mm angle of view on a 1.6x crop camera. Essentially its just cropped out the edges.

So why do people recommend that when taking a shot using a 1.6 crop that the shutter speed should be equal to that of the lens focal length times 1.6 to avoid camera shake/ blur in pictures? While in ff it is just a 1:1 rule? Shouldn't they both be calculated at a 1:1 ratio?

Just curious.

more reach.

a PnS camera has an 8-24 mm lens

does that mean I can take a pic at 24mm (85mm equiv) at 1/24 sec and get zero camera shake?

Erik_L wrote in post #10259501
more reach.

Is it? because I thought just the angle of view changed and not reach. Im defining a 24-70mm reach to be the same on both a ff and a crop camera. At least thats what I understand it to be

The fact is that the in-camera image made with an APS-C camera (roughly 22.5mm by 15mm) has to be enlarged more to fill an 8x12 inch print as compared to the in-camera image made by a 35mm film format camera (36mm by 24mm) being enlarged to fill the same 8x12 inch print. Any blur (due to either camera motion or something being out of focus) is enlarged more when making a print from the APS-C format than with a larger format. Thus, when using the smaller format, any motion blur needs to be smaller than with a larger format. This translates to needing a faster shutter speed to reduce the motion blur.

You must realize that the formula is a "rule of thumb", and does not necessarily apply to various individual photographers equally. One can hold a camera more steadily than another, etc.

What SkipD says is correct...has to be enlarged by 1.6x more in order to make the same size final print, and blur from motion is magnified more, along with the detail.

I appreciate the answers it certainly seemed to be this way when I take photos but I couldnt understand why.
So I wasnt trying to give Erik a hard time, just trying to figure it out. Thanks

It is also important to note that if you start cropping then you will be magnifying even more so you'll need even more shutter speed.

This is totally irrelevant to the original question but are D90's full frame?

I believe its 1.5x

YAH00 wrote in post #10259753
This is totally irrelevant to the original question but are D90's full frame?

Google can tell you. You could have found out almost immediately. But you decided you could wait 57 minutes for elitejp to answer you.

Well, I hope you made good use of that time.

EDIT: After glancing at your username, I reckon another Search Engine may be more appropriate.

I did actually. After asking the question, I searched and found my answer. I also read up on the advantages of full frame cameras.

elitejp wrote in post #10259525
Is it? because I thought just the angle of view changed and not reach. Im defining a 24-70mm reach to be the same on both a ff and a crop camera. At least thats what I understand it to be

It comes down to how you define 'reach'. The focal length of a lens tells you exactly nothing about the image that will be written to your memory card, unless you also know the sensor size and/or pixel density. There's no such thing as, say, a 70mm 'reach'.

• If you define 'reach' as meaning what is contained in the whole image (ignoring resolution) then an APS-C camera gives you 1.6x more reach. (This is my preferred definition, as I tend to think of resolution separately).
  
• If you define 'reach' as what is contained in a certain number of pixels, then the camera with higher pixel density gives you more reach, whether it is full frame or APS-C.

I think a good definition of reach is the resolving power (or circle of confusion) of the sensor and lens.

Ie It's no good having:
a) more pixels than what the lens can resolve and
b) a sensor not having enough pixels to capture what a lens can resolve.

In other words your reach is limited by the weakest link. We need to get away from crop factor because it's irelevant as far as the sensor is concerned, it's mostly dependent on pixel density. With the lens being the limiting factor.

cheers