Do you use your favorite medium format lens to shoot digital?

[NiallerM]

The format factor comes from the diagonal length ratio between the frames resulting in 1,5-fold and 2,5-fold factors for full-frame and medium-format compared to Fuji X (APS-C).

That's the crop factor. Sensor size is distinct from focal length. My observations with the etup aren't restricted to the image size, although it is generally considered to be a good indicator.

I think you may also be making the mistake that effective focal length is based on a full-frame comparison as a baseline, not on the sensor or film size for which the lens was originally designed..

 

[Alexander6x6]

Also, why do you insist on referring to aperture stops as "speeds"?

Your question must be re-addressed to a native speaker. who introduced the term "fast lens":
"A faster lens means the maximum aperture is larger, and more light will hit the sensor compared to a “slower” lens. This is usually expressed in an “f-number.” The smaller this number is (like F2. 8), the “faster” the lens is, and vice-versa."

 

[NiallerM]

Your question must be re-addressed to a native speaker. who introduced the term "fast lens":
"A faster lens means the maximum aperture is larger, and more light will hit the sensor compared to a “slower” lens. This is usually expressed in an “f-number.” The smaller this number is (like F2. 8), the “faster” the lens is, and vice-versa."

You said:

speed (f-stop wide open)

 

[Alexander6x6]

You said:

> speed (f-stop wide open)

It has the same meaning:

"Lens speed is the maximum aperture diameter, or minimum f-number, of a photographic lens. A lens with a larger than average maximum aperture (that is, a smaller minimum f-number) is called a "fast lens" because it can achieve the same exposure as an average lens with a faster shutter speed."

 

[Alexander6x6]

That's the crop factor. Sensor size is distinct from focal length. My observations with the etup aren't restricted to the image size, although it is generally considered to be a good indicator.

I think you may also be making the mistake that effective focal length is based on a full-frame comparison as a baseline, not on the sensor or film size for which the lens was originally designed..

I spent about eight years actively participating in the projects to adapt medium-format lenses for digital mirrorless cameras. In all those years, you are the first person to tell me that I am wrong.

 

[MattKing]

Moderator hat on:
Gentlemen - please!
Hat off.
Be cautious about any such analysis where the sensor/frame sizes being compared have different aspect ratios.
When those aspect ratios differ, there are actually four different equivalencies:
1) short dimension of the frame;
2) long dimension of the frame;
3) diagonal of the frame; and
4) area of the frame.
So you can have four different answers, all of which are right, even though their appropriateness depends on the use being made of them.