90D. Well that’s disappointing for us 7D2 users

Started 2 months ago | Discussions thread
Lee Jay Forum Pro • Posts: 54,794
Re: 90D. Well that’s disappointing for us 7D2 users
1

thomste wrote:

Lee Jay wrote:

TheBlackGrouse wrote:

And while saving space and weight a crop body also gives an in-built 1.6 teleconverter without penalties (losing stops, slower AF).

Cropping is exactly the same as adding a teleconverter - the same loss of light, just accounted for differently.

Adding a teleconverter to the lens makes the combined optical system slower by the teleconverter ratio (multiply f-stop by that ratio).

Cropping reduces the total light captured by the exact same amount but does so by literally cropping out some of the light, either by cropping or by reducing sensor size.

In fact, if you think of the teleconverter as being added to the body, rather than to the lens, you can think of it as optically reducing the sensor size (and the pixels contained therein). Same thing.

TANSTAAFL

So does this mean that you get the same result shooting with a 7dii and a 400mm lens at f4 or a 5div with 400mm lens + 1.6x extender at f5.6?

Well, it would be f4*1.6=f/6.4, but yes.  As the other poster mentioned, this is assuming TC optical perfection which isn't far from the truth for modern ones, especially the IIs and IIIs from Canon.

But cropping, whether in-camera or in-post is the same as a teleconverter from the point of view of light captured, DOF, field-of-view, etc.  There can be differences especially with total pixel count.  For example, if you compare a 7DII to a 5Ds+1.6TC, the 5D will have more pixels on the target.

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Lee Jay

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