DXO does it again

[privatebydesign]

I think the flange distance on the EF is fractionally less than the Nikon F.

You are right, 44.00mm vs 46.50mm.

Is that enough to change the optical design, or does it merely frame slightly longer on the nikon?

It would depend on lens design and what angle the light coming through to the sensor.

What I'm asking, though, is whether the sigma/zeiss/tamron/tokina/whoever lenses for EF vs F are different anywhere other than the back end.

If one were able to control the position of a camera such that you could take two pictures behind F and EF mount versions of the same lens with the sensors in the exact same physical location and orientation, would the pictures be identical excepting any potential crop from the horizontal dimension of the nikon FX sensor being slightly shorter than that of the canon full frame sensor? Or would one have a tighter crop than the other for optical reasons (lens further from sensor)?

I've always assumed that the designs were basically modular, where the manufacturer can put whatever back end (i.e. mount) on they need to based on assumed demands, but am wondering how a different flange distance may affect that.

Dilbert is 100% wrong.

The same lens in different mounts will pass the light to the different sensors at the same angle, the length of the mount is irrelevant, it is the distance from the rear element to the sensor that is important and will be consistent across different mount versions of the same lens.

The only situation where it might be different, and it would make no commercial sense to do it, was if the rear element was in different places for each version, but this would require different element spacing and optical formulas for each version and would have no real benefit.

 

[3kramd5]

And the mount handles the positioning. Makes sense

 

[Diko]

3) the transmission score (T-stop) of the lens.

What is that?

 

[Loswr]

3) the transmission score (T-stop) of the lens.

What is that?

Well, depending on context a T-stop is either a) the measured amount of light passing through a lens (vs. f-stop, which is calculated based on focal length and iris diaphragm diameter) or b) a station in Boston's subway system, which is called the T.

 

[Sporgon]

3) the transmission score (T-stop) of the lens.

What is that?

Well, depending on context a T-stop is either a) the measured amount of light passing through a lens (vs. f-stop, which is calculated based on focal length and iris diaphragm diameter) or b) a station in Boston's subway system, which is called the T.

Ah-ha ! I get it now. DxO set their lighting from the T stop. That explains a lot - but I thought they were French.

 

[Loswr]

3) the transmission score (T-stop) of the lens.

What is that?

Well, depending on context a T-stop is either a) the measured amount of light passing through a lens (vs. f-stop, which is calculated based on focal length and iris diaphragm diameter) or b) a station in Boston's subway system, which is called the T.

Ah-ha ! I get it now. DxO set their lighting from the T stop. That explains a lot - but I thought they were French.

Hey, be nice. They're actually rebuilding a bunch of the stations with lots of exterior glass, in fact the Government Center station just reopened today:

That's way too much light for a proper DxO test. They could use the tunnels, though.

 

[j-nord]

If you dig into DXO metrics they are very useful for comparison but if you compare their overall scores or read the reviews you are absolutely wasting your time. Nikon gets what they pay for with the overall scores and review headlines