Fast Full Frame Unique Zoom Lenses
- Thread starter Richard-CN
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I think we need an automatic button to click everybody time this suggestion of making dedicated teles for APS-C is posted.
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Why oh why is there no industry desire to produce a wide-aperture portrait lens for full frame? 50-1XX f/2? Why oh why...
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The 28-45mm f/1.2 would do it for me, it's the perfect range 
That lens would be crazy.
To be honest, I wouldn't buy it. I barely use f/2 on my 28-70mm f/2, I was just lucky I got it for about the price of a RF 24-70mm f/2.8 on sale, and even now sometimes I question myself if I should replace it with the 28-70mm f/2.8 STM, mostly for the weight savings, BUT it would be exciting seeing a lens like that.
That lens would be crazy.
To be honest, I wouldn't buy it. I barely use f/2 on my 28-70mm f/2, I was just lucky I got it for about the price of a RF 24-70mm f/2.8 on sale, and even now sometimes I question myself if I should replace it with the 28-70mm f/2.8 STM, mostly for the weight savings, BUT it would be exciting seeing a lens like that.
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Yup…specially now, that I added the 45mm f/1.2 to my kit, which means I’ll always have something faster available in my bag and in my standard range, but the 28-70 is fully paid so, at least for now, it stays. Also, it’s not that it’d make much of a difference with my cameras, but this idea implies a downgrade, which would need to be very well considered. The 28-70mm f/2 is my most used lens for work.Omg, that weight saving would be insane, probably a recordsaving nearly 1 kg... crazy
The 45 1.2 is a complementary lens to me, hence going with such a budget option instead of, for instance, a VCM prime. The emphasis of my working kit is on the 28-70. If I replaced my main lens with a slower and lower end option, I’d probably have to reconsider the quality of the prime lens to go with it as well.
These lenses definitely reach new heights. It’s not just about specs, they can revolutionise entire kits for many users. To me, the 28-70 f/2 replaced two f/1.4 Art Primes and the EF 24-70 II. I actually sold three lenses after getting it.
I could imagine a 28-45mm f/1.2 going for 8~10k though
Insane loss of quality? To be honest, with my cameras, I doubt. I’d be more concerned with the retractable mechanism, weather sealing and autofocus performance (the f/2 zoom is very, very capable regarding low light autofocus).
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OM 150-400mm is about a stop faster at 400mm than the Canon 100-500 though. Also internal vs. external zoom. Bad comparison I guess.
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You have entirely missed @neuroanatomist 's point. The image circle of a 400mm lens is much greater than required to cover an FF sensor, and the lens can't be made smaller for crop or for M4/3. Most here know that so see my earlier post:
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You completely missed the point of my comment. Using the OM 150-400 and the Canon 100-500 to prove his statement is an inappropriate comparison.
I didn’t disagree with his statement.
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He did say in his statement that : if OM made a FF camera, the lens (OM 150-400) would work on it, which is the whole point he is making. If you didn't disagree with that then you should have made that clear. Otherwise, it reads as if you are contradicting him.
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It's rather complicated to understand, a least for me. The HM element (HM = Holographic Mirror) acts like a catadioptric lens. The centre of the front allows transmission but directs light to peripheral areas of the back surface that reflect it back to reflective regions of the front surface that then reflect it to transmissive regions of the back surface. So the light is folded as in the patent for one round trip. It requires incredible accuracy of engineering at the nanometer level to work.
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I really enjoyed using the Sigma 24-35 f/2 for a few years. Like 3 primes.
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So for example if you look the lowest path of those 3 lines starting from down drawn on the patent, it bounces once and then goes through the second time.
But if you had another photon coming on the red arrow I drew (poorly) so it enters the same trajectory as the bounced photon, would they both pass the same spot on the back of the lens or would the red arrow photon make bounce while the other one goes through.
Photons don't have memory so if they hit the same spot, they should both behave the same. But then the red arrow path wouldn't make the bounce. So there's something strange here, maybe they left out something critical.
But if you had another photon coming on the red arrow I drew (poorly) so it enters the same trajectory as the bounced photon, would they both pass the same spot on the back of the lens or would the red arrow photon make bounce while the other one goes through.
Photons don't have memory so if they hit the same spot, they should both behave the same. But then the red arrow path wouldn't make the bounce. So there's something strange here, maybe they left out something critical.
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You have to use the wave nature of light to account for the interference/diffraction/phase shift etc and not think about bouncing photons.
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Ok, can you explain how that helps it bounce only once while another photon/wave on same trajectory wouldn't if it had already completed one bounce?
Fyi I have masters in physics so complex explanation is ok. I just can't figure out how that could work the way they have it in the picture, other than that they haven't told something critical about the design and how it operates.
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It's not that Canon didn't tell us, it's that Richard didn't pass along the full explanation. He hints at it, though, right at the start: "I had previously discussed these as quarter-wave optical designs...," in reference to the quarter wave plates (QWP) that convert linearly polarized light to circularly polarized light and back.
Details are in the patent, and the light manipulation you're missing is polarization, more than once in the optical path and both linear (POL) and circular (QWP2, QWP1), plus selective reflection/transmission.
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