AUGS said:

So far, Canon themselves has not officially announced or declared when (or if) this lens will be released. Dates or other information, may be informed or otherwise, but have not come directly from Canon themselves. So any rumored dates and/or details should be taken with a grain of salt. There are many product development steps and any or all of them may lead to a delay.

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It's also apparently looking like an F/5.6 to F/6.3 lens now as per latest information...
instead of F/4, F/4-F/5.6, constant F/5.6.

neuroanatomist said:

Incidentally, maybe Gemini did get it wrong. I took a pragmatic approach rather than a mathematical one, made a circle with a diameter of 39.32 units (19.66 x 2) and centered a 24 x 36 unit rectangle on it, then measured the area of the excluded portions of the rectangle vs the whole rectangle (pixel counts of a screenshot, but that would not affect a % measurement). It came out to ~2.07% of the FF sensor area, i.e. worse than Gemini calculated.

View attachment 227494

Still nothing to lose sleep over, IMO, much less prevent me from buying a lens requiring such correction.

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I had checked it with ChatGPT, which gave ~1.4%. I wonder what is going on?

EricN said:

It may depend on the topic. I've tried using them to help create charts for understanding data regarding controversial topics and they make the kind of mistakes only the worst politicians could make. Which goes back to your "some humans."

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When it's routine calculations they are very good. When there is proper on-line documented information, like say government websites on tax and law, they are fantastically useful. When there is sparse or conflicting information, then they can be dreadful. Amusingly for me, I've done searches for camera info and got referred to my own threads on CR!

David_B said:

I presented some calculations from gemini about image coverage of the smaller circle on the sensor and its answer was 98.5%. ... Did Gemini get it wrong? It's not a trivial calculation to work out the area lit by the smaller image circle.

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Incidentally, maybe Gemini did get it wrong. I took a pragmatic approach rather than a mathematical one, made a circle with a diameter of 39.32 units (19.66 x 2) and centered a 24 x 36 unit rectangle on it, then measured the area of the excluded portions of the rectangle vs the whole rectangle (pixel counts of a screenshot, but that would not affect a % measurement). It came out to ~2.07% of the FF sensor area, i.e. worse than Gemini calculated.



Still nothing to lose sleep over, IMO, much less prevent me from buying a lens requiring such correction.

AlanF said:

Be fair. There are some humans even the worst AI couldn't stoop low enough to match. For calculations like these, Gemini, ChatGPT etc are very reliable.

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It may depend on the topic. I've tried using them to help create charts for understanding data regarding controversial topics and they make the kind of mistakes only the worst politicians could make. Which goes back to your "some humans."

Berowne said:

My fast 50mm Prime for a very affordable price (600€), excellent optical performance but quite slow AF is a second hand Zeiss Milvus 50mm/ f1.4. Only downside is the weight ...

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Do Zeiss Milvus (and Otus) RF/EF mount lenses have AF?

Richard CR said:

depends, you'd have to restrict the movement, you couldn't, for instance, shift in different angles - you could only move up and down, and left and right from center.

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Rotation could be encoded, too, right? The position of the sensor relative to the image circle could then be calculated, and since DLO is (as I understand it) based on calculations from the optical formula of the lens, it should be possible to apply corrections to any orientation. For Canon, at least. I believe that DxO, for example, uses empirical measurements to drive their lens profiles and in that case, developing a profile for such a lens would likely be a prohibitive investment.

justaCanonuser said:

Richard raises in this very interesting comparison of reviews a question that I ask always myself: do I want perfection or "artistic" imperfection?

Being myself scientifically educated (physics) I always love to check sites like Photozone, now OpticalLimits, with thorough lab reviews - that's the sort of "scientific" Dr. Jekyll in me. But when it gets to real life photography, the "artistic sort" Mr. Hyde could be set free, and then I enjoy shooting with gear that isn't technically, in particular optically, perfect - depending on the subject, of course. Its the street & people side of photography in which I often love to get an imperfect, vintage look (not quite Lomography, that's too crappy for my taste). By contrast, when I shoot wildlife or macro, I want technical perfection. Getting to the 45/1.2 here, this would be a nice candidate for the first approach to real life photography, so I can understand well why some reviewers are more enthusiastic than others.

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I like to think that I too have "2 sides of my photographer's soul", so to speak: the more analytical one and the artsier one
But I do not see them in conflict, I see it more as the artsy side leaning on the technical side.

In the specific, I prefer to capture the image in a way that the data is as optimal as possible and I can always tweak the data in an less than optimal ways in post. I have done so with my latest fashion shoot, where a lot of "character" was added afterwards (haven't shared those images here since they were taken with my MF rig). There's plenty of plug-ins to simulate film and lens defects in post (Nik had a great one, not sure it is still there in their latest incarnation).

Having said so, like you I suspect, I've never based my buying decisions on reviews. I treat them as food for thought, not as decision makers.

stillviking said:

This could be the missing lens in the Canon setup for underwater photography. I'm very interested in knowing what the minimum focus distance is.

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I napkin'ed mathed it out to around 20cm. i could be mistaken though.

99cm length is far too big, even for my largest backpack!

neuroanatomist said:

If the movements of a TS-R lens are encoded, it would be possible to use a lens profile to correct for asymmetrical distortion and vignetting. In theory, that means Canon could actually 'cut the corners' of a TS image circle, making it smaller than strictly required. I highly doubt they'd do that, but it would certainly give the optical purists conniptions if it happened.

View attachment 227493

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depends, you'd have to restrict the movement, you couldn't, for instance, shift in different angles - you could only move up and down, and left and right from center.

This could be the missing lens in the Canon setup for underwater photography. I'm very interested in knowing what the minimum focus distance is.

Richard CR said:

I'm not sure a TS-R of 12mm is even possible, if it did, it'd probably look something like the Nikkor 7.5mm, which would be highly amusing to be honest.

Hah. i guessed around the correct number, it'd be 7.8mm, assuming a 10mm shift amount, or a full 66mm image circle diameter.

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If the movements of a TS-R lens are encoded, it would be possible to use a lens profile to correct for asymmetrical distortion and vignetting. In theory, that means Canon could actually 'cut the corners' of a TS image circle, making it smaller than strictly required. I highly doubt they'd do that, but it would certainly give the optical purists conniptions if it happened.

I'll take one

I'm still using the Sigma EF 14mm f/1.8 with an adapter. Since I use it quite often, I’d gladly upgrade and get rid of the adapter.
If Canon releases a 14mm f/1.4 that’s sharp with minimal coma, I'm willing to splurge whatever it takes for that one

I personally don’t miss OIS on this lens (the Sigma), and I wouldn’t mind if Canon released their version without it as well. To be honest, I’m also not too concerned about digital corrections or stretching. Hopefully it doesn’t vignette too much though, because I’m already shooting with these types of lenses at high ISO sometimes, and I don’t want to push corner brightness corrections too far due to noise.

David_B said:

Find a scraggly old tree and take a photo of it. How many straight lines are in that? Put it in your raw image editor of choice, apply a lens profile and compare the before and after. Sure they're different but does one or the other make or break the image?

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I wouldn't think so, no. In your image of that scraggly old tree, do you believe that digital correction to fill in the corners would break the image, relative to optical correction?

David_B said:

You're assuming I shoot straight lines. Sounds like a boring photo to me. I also don't put faces at the edge of the frame if I can help it.

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If all you shoot is landscapes, it likely doesn't matter either way. Straight lines are most often human-made, and if you're taking pictures of humans there are often straight lines in the scene.

David_B said:

I presented some calculations from gemini about image coverage of the smaller circle on the sensor and its answer was 98.5%. On a 45MP that's ~675,000 pixels (1.5%) that aren't usable. For the R1, 1.5% is 360,000. How'd you come up with 11,400 out of 24,000,000? Did Gemini get it wrong? It's not a trivial calculation to work out the area lit by the smaller image circle

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Perhaps I could have made it more clear. Regarding the area of the image, I was referring to the RF 24-105/2.8 Z, as I stated in the post. The 19.96 mm image height value on which you based your calculation is not universal, it's the value in a patent for the wide end of one possible optical formula of a 50-150/2.8 lens (presumably not an L lens, and regardless, if such a lens is produced based on this patent it may not have that image height). Different lenses will have different image heights. As to how I arrived at my value, I empirically measured it in an uncorrected RAW image from the RF 24-105/2.8 Z at 24mm.

One other relevant bit of information is that the amount of mechanical vignetting is dependent on focus distance, it increases as the lens is focused closer. I presume that in their patents, Canon is specifying the image height as focal length is specified, with focus at infinity. In the 24-105/2.8 Z image that I used, the lens was not focused at infinity, but was focused on a reasonably distant subject (~40 m). The mechanical vignetting is noticeably greater with a close subject, for example (these are uncorrected, high ISO images):

A Canon competitor to the magnificent Sony 14mm f/1.8 GM would be AWESOME!

I hope it'll be good for Astro photography! It would probably also be an interesting choice for landscape timelapses.

How about if Canon creates a pocket camera, not a phone wannabe or a do-everything super zoom blah blah. Fast lens, fixed or a modest zoom illuminating a real sensor, "1 inch" or "aps" (jeez sensor sizes need to standardize to area or xy dimensions) not a phone-sized toy. Modest 4k video specs, but stills focused on stills. A camera that can go where we take our phones but blow them out of the water with IQ. Ricoh's GRIV seems to fill the niche but at a ridiculous price.

EricN said:

Current AI for public use are about as prone to errors as humans.

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Be fair. There are some humans even the worst AI couldn't stoop low enough to match. For calculations like these, Gemini, ChatGPT etc are very reliable.

Mekos said:

I'd prefer a TS-R 12mm f/2.8 over that one (or RF 12mm f/2).

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I'm not sure a TS-R of 12mm is even possible, if it did, it'd probably look something like the Nikkor 7.5mm, which would be highly amusing to be honest.

Hah. i guessed around the correct number, it'd be 7.8mm, assuming a 10mm shift amount, or a full 66mm image circle diameter.

justaCanonuser said:

That's exactly what I learned in the past, say, 15 years reading lens reviews, e.g. the ones of lensrentals. In particular these showed that the variation of the production quality of lenses gets smaller and smaller over the years. They also showed that Canon is one of the leading manufacturers in terms of stable optical quality, e.g. Nikon struggled much longer with decentered lenses in their production lines (a typical Nikon problem back then in particular with tele lenses, unfortunately):

The Nikon 300mm f/4E PF ED VR Test: Or Why I Don’t Test Just One Copy

As most of you know, we generally test multiple copies of a lens when we evaluate it, simply because we are so aware of copy-to-copy variation. But I got caught between a rock and a hard place this week. We received exactly one copy of the new Nikon 300mm f/4E PF ED VR lens and [...]

www.lensrentals.com

Today, MTF charts aren't just showing the best case - the "lucky copy" - of a lens like in former times, they tell you what you can expect to get.

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There is still variation, unfortunately. I've tested multiple copies of some lenses that have outstanding reputations for consistency, including the EF 100-400mm ii that Lensrentals claimed to be one of the most consistent they have tested, and have seen differences. Even extenders, like the EF 1.4xIII varied. @neuroanatomist has mentioned occasions where the-digital-picture has had to change their copies because they were poor compared to his.

These are my predictions for the R7 (ii). Based off the recently released R6 iii and original R7.

Resolution ------------- 34.4MP Stacked.
Sensor Size ------------ Crop Sensor (22.3 x 14.8mm).
Sensor readout ------- 10ms or faster.
FPS -------------------- 15 mechanical
Sensor Stablization --- 8 Stops of 5 Axis Stablization.
ISO -------------------- 100-32,000 (100-51,200).
Video Format --------- 10/12bit H.265, CLog3.
Video Resolution ------ 6k30p OS, 6k60p LS, 4k60p OS. ~OS = OverSampled, LS = LineSkipping~
Processor -------------- DIGIC X, Faster version.
Storage ---------------- CFexpress & SD UHS-II.

This is based off my predictions and nothing more

David_B said:

The problem is the lack of evidence or more importantly, Canon's internal testing where they decided that 19.96 was acceptable. I mean it's great that you did something that you consider to be worthwhile evidence but your test bed isn't Canon's test bed and your image analysis isn't Canon's image analysis.

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Worth noting that Canon was certainly not the first manufacturer to 'cut corners' (literally) from the image circle. The fact remains, the ultimate arbiter is the consumer. If you don't like it, don't buy it. Their choice to rely on distortion correction to fill the frame does not seem to be impacting their market share. The RF 16/2.8 appears to sell very well, for example. If you prefer 'optically corrected' lenses, stick with EF for your wide angles.

Richard CR said:

3) what artifical conditions? yes, the MTF is calculated in Canon's case but their elements and most lenses are manufactured by machines, not humans anymore; the odds that the MTF will match reality have a fairly strong correlation.

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That's exactly what I learned in the past, say, 15 years reading lens reviews, e.g. the ones of lensrentals. In particular these showed that the variation of the production quality of lenses gets smaller and smaller over the years. They also showed that Canon is one of the leading manufacturers in terms of stable optical quality, e.g. Nikon struggled much longer with decentered lenses in their production lines (a typical Nikon problem back then in particular with tele lenses, unfortunately):


Today, MTF charts aren't just showing the best case - the "lucky copy" - of a lens like in former times, they tell you what you can expect to get.

David_B said:

I presented some calculations from gemini

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Current AI for public use are about as prone to errors as humans.

Old Man FL/FD said:

Thanks for the clarification. I Googled "*** slang" and some obvious offenders showed up. I wasn't aware of the previous controversy on this site.

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Fortunately, as a European, I can state that our system is called Galileo, which is harder to mistreat as an offending acronym (you'd have to invent something with seven words, for G. A. L. I. L. E., and O., so any willing offenders would need quite a bit of imagination)