Hey Maya,It's an intuitive way of thinking about it, but I don't have the knowledge to be quite so sure that this is exactly how it works .
From what I've read the difficulty in managing aberrations isn't quite "linear" with increasingly wider apertures.
It has aberrations . Point light sources at the periphery show more aberrations than, for example, the Sigma 40mm 1.4. Perhaps some astigmatism but I don't know how to interpret these well (it could explain what I don't like about the RF's bokeh off centre). It's also got quite a bit of CA.
I mean, it's a very well corrected lens, that's for sure. But off centre it's a bit off the truly world class mark that's all the rage these days.
You could argue that its vignetting already helps tremendously in that regard, at least in one axis .
I have no idea about apodization filters - hence why I'm curious to see how Canon will implement apodization with the 85mm DS, but it's kinda possible with undercorrected spherical aberration. This is how the Nikon 58mm behaves when shooting a very small, bright (and here, green) point light source is shot slightly in front and behind the focal plane. The gradient you see between the centre and the edge of the background blur is maintained even when the aperture is closed down. Of course that lens is a very extreme design that puts all its eggs in one basket, but it's an illustration of how it's possible to get an "apodization" like gradient, even at smaller apertures, by biasing the blur quality in favour of rear gaussian smoothness (at the detriment of front side blur, sharpness, focus shift, etc.).
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All the credit should go to Marianne Oelund, who initiated this thread on the subject, unfortunately now the pictures have been lost : https://www.dpreview.com/forums/thread/4031515
In the 1990s I played around using black magic marker or spray paint on CD case covers and holding them in front of the lens. It just occured to me my friend with an airbrush would have been able to do a better job...... or something like a transparent (LCD) display in the lens with high resolution which creates the apodization pattern Some menu item where you can draw you own apodization pattern in-camera.
But major drawbacks are that it is polarizing (sometimes helpful, always loosing ~1 stop of light) and I am not shure if it is possible to make optically "clear" displays with very uniform transmission and at least 128 precise gray levels ...
EDIT: Forgotten to say that there are some revived lens designs where the f-stop is chosen by f-stop-slots like the petzval from lomo: https://shop.lomography.com/en/petzval-85-artlens-canon?country=de -- make your own filters via 3D printing or / and painting with a gray marker on glass ...
EDITEDIT: Lomo thought about customization: right item of https://shop.lomography.com/en/petzval-special-aperture-blades
The difference is EF and RF are both EOS mounts with all electronic connections that speak the same exact language. This makes an EF to RF adapter little more than an extension ring with full communication. It's even less impactful optically speaking than an extender is, yet the top pros have no qualms about slapping an EF 1.4X III between their 1D X Mark II and a 400/2.8 III, 500/4 II, or 600/4 III.OK, say that "gap in the back" is 25mm. That means that to allow a TC, the EF lens needs 44mm film-to-flange distance plus 25mm = 69mm.
It's possible that the RF, with a 20mm film-to-flang disance, would be happy with 20mm + 25mm = 45mm. IF shorter film-rear element distance helps with telephotos, then the RF would still have an advantage.
On the other hand, even if the distance isn't crucial, I imagine they'll come out with RF versions of telephotos anyways. Even if it's not optically superior, simply being able to work without an adapter will appeal, on grounds of simplicity, reliability. Remember, the point of the EF mount was autofocus, yet Canon was happy to make some manual-focus-only lenses (the TS series) that couldn't take advantage of "the whole benefit of EF lenses." Canon didn't say, manual focus so might as well only release with the FD mount...
The first "Pro" EOS body, the EOS-1, was not introduced for 30 months after the first EF mount camera, the EOS 650. This is nothing new.One does get the impression that Canon had to release the mirrorless new generation of bodies and lenses ahead of their preferred schedule, which would probably have happened end 2019 with a pro IBIS and the RP together with 6-7 L lenses and 3-4 more mainstream and less expensive lenses like the 24-240. Nikon’s move and/or Sony’s growth forced an early and rather incoherent timing, with the R cobbled together and whatever lenses were ready for production, the rest following in a haphazard way. This is of course pure speculation
In the case of the tests Marianne Oelund has realised, it's rather spherical aberration that's at play, as she only tested for one color (green). And it's only valid in the centre of the frame, off-centre other aberrations pile up I believe to make things even way more complex.Hey Maya,
Thanks so much for the interesting reply! I absolutely did not realize CA was the specific cause of these bad bokehs, but more importantly I never realized that front bokeh and back bokeh circles would be so complimentary.
Bring on the gimmicks . I'd love that. Although it's not at the aperture stop, has anyone experimented with the EF to RF drop in filter adapter to see if interesting effects can be obtained bokeh wise ?These might be gimmicky but you could also have filters such as: 1) clear center spot surrounded by ND. Things would be be sharp front to back due to a pinhole effect, but also surrounded by blur. Almost like a double-exposure wide open and stopped down. 2) shapes such as stars. 3) random scattering of pinholes, giving the most jarring bokeh...
Right, but you can also tune it to be as disk-like on both front and rear. If it's exactly the same that would be ideal. Then you can correct it with the apodization filter. (Oh, I see you said the same thing!)Fine-tuning spherical aberration to enhance background blur comes at the cost of foreground blur. Besides in the case of the Nikon 58mm the aberration is so extreme that focus shift is significant and resolution not quite excellent.
Sure. If you had perfect disk highlights, you could then have a drop-in apodization filter that achieves this effect, (a sharp drop-off from center, but then slow drop-off to the edge), along with another that has no drop-off near the center and then drops off quickly towards the edge. There's so much room to play with this I think that it's a shame if it's not a drop-in.specifically designed to preserve some degree of spherical aberration to enhance background blur smoothness and progressive transitions : you can still read the "lensalign" text much further beyond the focal plane
Right.The first "Pro" EOS body, the EOS-1, was not introduced for 30 months after the first EF mount camera, the EOS 650. This is nothing new.
I remember when I started shooting (maybe a decade ago) that caring more about the body than the lenses was supposed to be the mark of a newbie. That caring more about bodies has become the norm is... interesting.I agree. This is just as true today as in the film era.
Well, we may not have cared about the body so much, but we certainly cared about the film.I remember when I started shooting (maybe a decade ago) that caring more about the body than the lenses was supposed to be the mark of a newbie. That caring more about bodies has become the norm is... interesting.
A decade ago the context was still entirely digital. If it were film, I wouldn't have been involved. The advice to people asking was still "get a cheaper body and a nicer lens or two".Well, we may not have cared about the body so much, but we certainly cared about the film.
Now the body is the film, so to speak, determining the look.
I don’t agree. It would be really hard to pick out a camera from the look of a photo. I’d go so far as to say it would be impossible, disregarding blind luck.Now the body is the film, so to speak, determining the look.
Yup! And the same during the film era. I belong to a FaceBook group for vintage lenses. People there are apt to post that they like the old manual film era lenses because they like the "film" look. It always gives me a chuckle. It fascinates me. It just seems I remember film and paper choice being huge determiners of "look" and that the "film look" actually comes from using film... not from the lens. I've even set up surveys (polls?) with side by side photos taken on the same subject, same camera, and then digital vs vintage lenses. Nobody has ever been able to tell the difference with any reliable accuracy. They say they can, but they all fail the test. Then they accuse one of rigging the survey. They cannot possibly be wrong. Some are even so bold as to put down exactly which lens was used. Funny as hell.I don’t agree. It would be really hard to pick out a camera from the look of a photo. I’d go so far as to say it would be impossible, disregarding blind luck.
Lighting, optics, and processing after the fact are what by and large gives unique looks.
Not exactly. The EOS-1 was introduced in 1989. Also introduced that year was its holy trinity of lenses: 28-80 f/2.8-4, 20-35 f/2.8 and 80-200 f/2.8. The first four lenses introduced for the EOS system, in 1987, were the 50 f/1.8, 35-105 f/3.5-4.5, 35-70 f/3.5-4.5 and 100-300 f/5.6, definitely not high end. There were some very high end lenses introduced between 1987 and 1989 but in 1987, the Canon F1 using the FD lens mount was king and Canon was introducing lenses for both the FD and EOS mounts. There was even an 85 f/1.2 for the FD mount. The 50 f/1.0 was the first lens that Canon introduced for the EOS mount while stating that it could not be made for the FD mount. That was in 1989.One substantial difference is that they didn't bother with the EOS-1 until there were enough EF lenses that a pro would actually buy an EOS-1.