Micro 4/3 Some thoughts on m43

[Iron]

Sony FE, with its very small mount diameter, manages to work exceptionally well with a range of top notch lenses available.

Sony's 46mm mount diameter is all good. I've seen online jabs at Sony regarding their smaller mount diameter and the future of the standard but the mount diameter doesn't really correspond to sharpness/survival of the mount. Physically and optically, the mirrorless advantage, I mean the absence of the mirror box, is only present on wide-angles or less than ~35mm. Beyond that, the rear element has to be pushed further out, negating any size/weight advantage. Sony knew this and they made their mount 46mm for their best compromise on lens sizes. Their mount diameter won't prevent them from making good lenses. Their engineers, optical and firmware, are very well-versed in dealing with their mount diameter.

I believe the comparison is usually initiated online by some Z-mount (55mm) users. There's no comparison becaue the only advantage that the Z-mount has, in terms of optics, is that the engineers have a bigger playground under the 35mm focal length vs the 46mm. It's easier to play with designs on the Z-mount than with the E-mount but, as proven by Sony, they won't be limited.

Lenses have been generally non-telecentric for a very long time, except that, as mentioned before, light rays on film strike half-circle objects, whereas, on a digital sensor, it's flat. As above, mirrorless technology allows lower-cost corrections so the telecentricity advantage can be rather minor. MFT engineers do have less firmware corrections to embed, though.

 

[fredlong]

I believe you're talking about the perfect telecentricity of Olympus DSLRs but telecentricity (near-perfect maybe) has long been a feature of MFT ever since its inception. As I've said before, their site was heavily dumbed-down but they had all the white papers available before. This link is safe:

Benefits of Micro Four Thirds

The Micro Four Thirds system's greatest appeal is to achieve high image quality, compactness, and lightness for photographers who want to enjoy a camera anytime, anywhere. The open standard means you can use lenses and camera bodies from a range of manufacturers. And that gives you high versatility, operability and usability.

www.four-thirds.org

. It talks about telecentricity as its third main benefit.

This is found in the link for those who do not wish to click it:
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The statements were referenced to some white papers and even the optical design of the old Olympus 17mm F2.8, which is not known for its performance.

To quote:
View attachment 518479
Yes, the MFT lenses' image circle covers that of APS-C-sized Super 35.

Here's another diagram from the link:
View attachment 518482
It says that it delivers light almost straight to the light-receiving section. On the four-thirds sensor. The diameter of the rear element is longer than the height of the sensor receiving more telecentricity in the X-axis. The diameter is shorter than the Y-axis and this is where the almost comes into. Light is slightly oblique at the edges of the Y-axis. On the MFT Super 35 sensor, which is currently being used in filmmaking, telecentricity is perfect in the centre but not in the edges.

Olympus four-thirds DSLR cameras achieve perfect telecentricity because the diameter of the rear element of the lenses is bigger than the sensor itself.

I don't know, It's not as perfectly telecentric as Olympus DSLRs but the telecentricity that we get on MFT is good enough for engineers to call the lenses telecentric.

If we disagree with them, we can always complain to any of these companies: https://www.four-thirds.org/en/contact/.
View attachment 518483
Olympus and Panasonic created the mount but, since it's an open standard, everyone in the list is part of the foundation, as well.

I’m going to guess this stuff was written by marketing people, not engineers because the numbers don’t add up. If the micro 4/3 mount was about twice the size of the sensor it would be about 45mm in diameter. It’s not, but the original 4/3 mount is about 45mm. It’s true that a smaller sensor that’s closer to the size the rear element means it’s possible to design for a more perpendicular projection.

My science-y mind says ‘almost telecentric” = “not telecentric” because words have meanings. To me, it’s like a slightly curved line can be almost straight, but it can never be straight because it’s curved.

Anyway, with or without rigidly defined telecentricity, micro 4/3 is pretty amazing. When I had a six month trial period with a "full frame" system I decided there wasn’t enough there to justify the size, weight and cost.

☮️

 

[Iron]

I’m going to guess this stuff was written by marketing people, not engineers because the numbers don’t add up. If the micro 4/3 mount was about twice the size of the sensor it would be about 45mm in diameter. It’s not, but the original 4/3 mount is about 45mm. It’s true that a smaller sensor that’s closer to the size the rear element means it’s possible to design for a more perpendicular projection.

We are actually on the same boat here. As I've said before, the site is heavily dumbed-down. It is also written by, assumingly, somebody who has English as a second language.

The mount cannot be twice the diameter of the image circle because acceptable image circles, projected from the rear element, generally go way past the diameter of the mount. It's just that the optical engineers have to choose the design with the best compromise. An example is the K-Mount with non-telecentric lenses. The image circle projected by all FF K-Mount lenses cover the Medium Format image circle. There is something wrong with the wording on the caption, "Mount standard that is about twice the size of the image circle."

My science-y mind says ‘almost telecentric” = “not telecentric” because words have meanings. To me, it’s like a slightly curved line can be almost straight, but it can never be straight because it’s curved.

I believe the article used almost in "light that is almost straight to the light receiving section." Again, we can question the wording in that statement. Telecentricity, since it's an optical engineering word, should have an envelope of tolerances, meaning the acceptable angles of light for the term telecentric to be applicable.

Anyway, with or without rigidly defined telecentricity, micro 4/3 is pretty amazing.

Totally agree. Even without firmware-level corrections, meaning if they are removed/invalidated, the effect of telecentricity of the native lenses is pretty amazing. If the so-called camera experts/writers/YTers/influencers undestand that, discussions will different, totally different.

We're talking about lens telecentricity for photography. Now think about the benefits of lens telecentricity.....for videography! That, my friend, is a topic for another day.