IRB Kirk said:

A Canon Christmas
Beneath the tree with lights aglow,
A gift awaits in ribboned bow.
Not toys, nor sweets, nor winter wear—
But lenses gleaming, beyond compare.
A Canon rests in silent grace,
Ready to capture each smiling face.
From frosty mornings to twinkling nights,
It frames the season in pure delights.
Snowflakes dance in crystal streams,
Preserved forever in holiday dreams.
Each shutter click, a carol sung,
A timeless story for old and young.
So raise your glass and cheer with glee,
For Canon keeps our memories free.
This Christmas joy, both near and far,
Lives in the magic of your DSLR.

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Richard CR said:

I recall when I did testing, I had a difficult time seeing the diffraction correction effects. They were quite subtle. The aberration correction, especially at the time the Canon EF 85mm F1.8 USM, which had the worst PF known to the modern photography universe, would clean up amazingly well.

That was what impressed me the most - since PF was troublesome to correct in post.

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neuroanatomist said:

They’re all 85mm lenses (or close enough with rounding). The likely patent for the RF 85/1.4 VCM has it as an 82.6 or 82.9mm f/1.45 lens, but similarly the likely patent for the RF 85/1.2 is 82.3mm f/1.24. The explanation is not a difference in real focal length.

I eschew YT videos (DIY home repairs notwithstanding) but I did scrub to the ~7 min mark to see it was a noted in a focusing speed comparison with objects arranged in a table and in a portrait comparison. The reviewer failed to provide the proper technical explanation, which is unfortunate but unsurprising.

What’s really going on is that the focal length of a lens is specified as the distance from the rear nodal point to the sensor with the lens focused at infinity. When a lens appears to have a wider FoV (shorter FL) with closer subjects (as in the YT reviewer’s examples), that’s due to focus breathing. That’s why, for example, the EF 100/2.8L Macro has the FoV of a ~68mm lens at 1:1 magnification.

Canon touts the 85 VCM as having minimal focus breathing, which is desirable in a lens intended for hybrid use (lack of focus breathing is one of the reasons cine lenses are so expensive). Focus breathing is not necessarily linear with subject distance, and I suspect what’s happening with the 85 VCM is that Canon’s design puts most of the breathing closer to infinity, so there’s relatively little change in FoV with subjects at different ‘normal’ (for people) distances. Doing so is facilitated with modern focus-by-wire lenses where a microchip instead of gearing is controlling focus motor movement.

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Exploreshootshare said:

Thx Richard!
I too wish y´all a merry Christmas and happy new gear...ups, I meant a happy new year of course

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el peso said:

Are you sure the compared lens is strictly 85 mm? Maybe its FL is longer than 85mm?

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EricN said:

It's an interesting concept. I have thought of anoth
using a curved sensor, but it's probably quite difficult manufacture and might potentially require a dedicated sensor and lens pairing

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Del Paso said:

I'm no scientist at all.
But wouldn't it be an easier way to get rid of all these geometric correction issues to "simply" design MF lenses and use them on FF (like TS lenses)?
Thus, they could make use of the best portion of a lens' projection circle. Could it be the recipe behind the RF 1,2 50 & 85 in order to also get sharp corners at f/1,2?
OK, cost would significantly go up...
But, as I wrote, I'm no scientist., and still hoping for a 35mm f/1,2...

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EricN said:

It's an interesting concept. I have thought of anoth
using a curved sensor, but it's probably quite difficult manufacture and might potentially require a dedicated sensor and lens pairing

Click to expand...

Richard CR said:

I recall when I did testing, I had a difficult time seeing the diffraction correction effects. They were quite subtle. The aberration correction, especially at the time the Canon EF 85mm F1.8 USM, which had the worst PF known to the modern photography universe, would clean up amazingly well.

That was what impressed me the most - since PF was troublesome to correct in post.

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Chig said:

Yes, the SA can be nice for a dreamy look or a rather harsh look (with the 3rd shot at neutral setting) like these shots of my neighbour's magnoliaView attachment 227213View attachment 227214View attachment 227215

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Del Paso said:

I'm no scientist at all.
But wouldn't it be an easier way to get rid of all these geometric correction issues to "simply" design MF lenses and use them on FF (like TS lenses)?
Thus, they could make use of the best portion of a lens' projection circle. Could it be the recipe behind the RF 1,2 50 & 85 in order to also get sharp corners at f/1,2?
OK, cost would significantly go up...
But, as I wrote, I'm no scientist., and still hoping for a 35mm f/1,2...

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Click said:

Lovely shots, Sir. Merry Christmas!

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AlanF said:

I attempted some testing for the correction of diffraction using DLO and found limitations in lenses where it could be applied. It can be applied to the RF 200-800mm on the R5ii and with the 1.4xTC but it is not compatible with the 2x. It is compatible with the 2x on the RF 100-500mm. And it is not compatible with the RF 100-400mm on the R7. The DLO box was greyed out n those incompatible cases.

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