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.

 

[Sirius Glass]

My digital camera Nikon Z7ii has two zoom lens built for the camera 28mm to 200mm and 16mm to 25mm and a 150mm to 600mm zoom lens but for Nikon film camera and has a 2X extender and a Z7ii adapter.

 

[NiallerM]

> 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."

That's a fast lens, not a "fast f-stop".

 

[NiallerM]

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.

What "projects"? Industry run? Can you post the results?

 

[Alexander6x6]

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.

Please correct me if I'm wrong.

The angle of view of a lens is the only parameter that makes it possible to determine the equivalent focal length of the system with different sensor or frame sizes.
One can use the first three parameters you listed for that purpose: the short side, the long side, or the diagonal of each frame.
I use the diagonal of the frame because my final images vary greatly (from 84x73mm to 108x53mm), so using either the short or long side would not be accurate.

See below two Excel tables I created on the topic of our discussion. The first compares standard prime lenses of four systems. The second compares the Mamiya 645 80mm lens adapted to the APS-C system with others in the sense of its effectiveness.

 

[NiallerM]

A spreadsheet in this form is nothing but tabulated assertions. It doesn't gain truth by being nicely presented. What are the workings behind it, and what specs are you referring to in it?

 

[NiallerM]

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.

Aye. I'll stop forthwith.

 

[loccdor]

I've done a lot of testing of the Carl Zeiss Jena Sonnar 180mm f/2.8. It would be a good candidate to adapt to digital of any sensor size.

Through testing it on 35mm film I found that the central portion, even with a teleconverter, out-resolves my ability to digitize the film at 36 megapixels with pixel shift, as long as you stop down the lens to f/5.6. Without a teleconverter, it out-resolves wide open.

Then I shot a 6x6 film frame and digitized it with stitching at around 120 megapixels. This was the first time I noticed any aberrations from the lens, it only happens towards the corners of a big MF frame.

Not bad at all for a 5 element lens you can buy for a few hundred dollars.