Canon reveals its first two 8K broadcast lenses, the UHD-DIGISUPER 51 and 7x10.7 KAS S

"compatible with 8K broadcast cameras that feature 1.25" sensors"
No word about 2/3". Fractions are not your core competence, or?

There are no fractions involved. The 2/3" is in reference to vidicon tubes that have been used in decades. The actual sizes are in mm.

Still the 1.25" tube would be the larger tube.

"Depth of field for the same field of view is inversely proportional to the sensor size (e.g., the diagonal)."

No, it is not. There is also a lens and an aperture involved.

Okay, I left out the "same relative aperture" part of the effect of sensor size. I thought that was understood, as well as distance to the subject. If you have a larger sensor, you need a longer focal length for the same field of view. By the time you do all of the algebra, DOF is inversely, linearly proportional to sensor size.

The second part regarding magnification is also true, but most applicable to changing lenses with the same camera, and moving so that the subject is the same size on the image plane. With a longer lens, you move further away, which increases the DOF to exactly offset the effect of focal length. The background will be OOF to the same extent, except there is less of it (narrower FOV).

If these concepts seem counter-intuitive, I suggest you refer to "The Camera" by Ansel Adams. It has lots of pictures ;)

"1.25 inch sounds really small"
It is four times the area of 2/3" used for many for 4K cameras, and also for many big budget movies a few years back.
E.g. it is the format Sony is using its first 8K broadcast camera: https://pro.sony/ue_US/products/4k-and-hd-camera-systems/uhc-8300

AFAIK, all 8K broadcast cameras so far are either this 1.25" [18.5mm diagonal] or 4/3" [22mm diagonal] format.

"I had no idea these huge lenses were attached to cameras with smaller sensors though."
These lenses are already massive (about 50 pounds/24Kg) and expensive (over $200,000); think how big a lens with this wide a zoom range would be for use with a camera using the 35mm film format?!

"ISO is not an issue because the field/studio is usually well lit?"
This format and even 2/3" format is also used in the field, for sports and such.
https://www.usa.canon.com/internet/portal/us/home/products/list/lenses/broadcast/4k-uhd-field-box-lenses
Big _apertures_ (front elements) is what give low-light speed.

@Ed Ingold Yes you left out the assumption that the larger format uses a lens of larger effective aperture diameter in proportion to the increase in linear sensor size and focal length, and thus with an aperture area and front elements larger in proportion to sensor area. The usual thing of attributing shallower DOF and better low light/ high speed performance to sensor size instead of lens size.

These broadcast lenses give speed (and low DOF if needed) through big heavy front elements, leading to very low minimum aperture ratios; as low as f/1.15 on some Canon lenses for 2/3” format 4K broadcast cameras.

"Ziginox JACS, I see you're showing your ignorance yet again."
No, you are showing your ignorance and lack of reading ability: although DOF can be computed from format size, focal length and aperture ratio, it is clearly not dictated by format alone: once one compares at equal FOV in different formats(adjusting focal length), you get the same DOF when using the same effective aperture diameter (focal length divided by aperture ratio) which very roughly means "equally wide front elements give equal DOF".

It is pointless to assume equal aperture _ratio_ (i.e. smaller aperture sizes with smaller formats) when comparing DOF; its is just a round-about way of saying that smaller apertures give more DOF.

BTW, these broadcast "box lenses" have huge effective aperture diameters of about 200mm!

P. S. Why do you assume a different subject distance with a different format?! Clearly these broadcast cameras will be used at the same subject distance regardless of sensor size!

It's has been that way since ever. Broadcasting world is just for a few players, on the camera side is JVC, Sony, Panasonic, and even Hitachi. From the lens side is mostly Canon and Fuji.

Thanks Chris, you made me look around and see how Fujinon and Canon lenses dominate broadcast video, with standard mounts like B4. Sort of like the PL mount that dominates in cine-cameras.

Wouldn’t it be nice to have one open standard mirrorless mount for each still camera format size?

@ J A C S Maybe, but there is no need to mess with crop factors and "effective aperture ratios": what matters is the ratio between pixel pitch (which limits sensor resolution) and aperture ratio (which effects lens resolution). The obsessive standard of "Airy disc no wider than a pixel" gives a threshold of roughy f-stop equal to the pixel pitch in microns; actual experience shows that diffraction only starts to affect resolution noticeably between 2 and three times this; to be cautions, when aperture ratio is twice the pixel pitch.

(And why mention f/9? This lens will surely be faster than that, and this format can get adequate DOF at lower aperture ratio than that.)

With the slightly over 2 micron pixel pitch of this sensor, diffraction comes into sight between about f/4 and f/6. Judging by previous lenses in this product line, the minimum f-stop is likely to be under f/2 over much of the zoom range, and no worse that about f/3 or f/4 at the long end — if so, no worries.

Ninety bucks? I'll take two! ;-)

(pesky comma/decimal issue...)

Yes the decimal comma vs point issue is irritating. And this is the only one where I reluctantly agree that US is right. We German influenced countries will change to decimal point if you remove all of your bad habits, like moving fork back and forth while eating and calling milliard a billion. And please? SI-units? And what about your weird way of writing dates? Today is 2019-11-13! Most significant digit to least significant digit. How hard can it be?