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Optics Theory - This forum is aimed towards the TECHNICAL side of photographic OPTICS THEORY. There will be some overlap by camera/manufacturer, but this forum is for the heavy duty tech discussions. This is NOT the place to discuss a specific lens or lens line, do that in the appropriate forum. This is the forum to discuss optics or lenses in general, to learn about the tech behind the lenses and images. IF you have a question about a specific lens, post it in the forum about that type of camera, NOT HERE.

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Old 1 Week Ago   #81
goamules
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Optics (lens designs and glass) can only represent what they are seeing. There is no "magic", and when someone above said "sometimes xyz lens will do it, sometimes not" it's pointing to the truth. That a look comes not from a lens make or design as much as about composition, lighting, and the attributes of a lens including it's:

1. Speed
2. Focal Length (wide, normal, or narrow for format)
3. Optical aberrations

The first two will create the same depth of field for any lens that is the same focal length and aperture. A 50/1.4 Canon LTM will be the same as a 50/1.4 Nikkon LTM. The last is what causes a certain "bokeh" like swirl (coma) or disk out of focus highlights versus donut rings. Or a sharp across the frame image, versus a "soft" image in those two examples.

The so called "3D look" is a totally subjective thing, that really isn't a thing at all. They are looking at a photo with either a short depth of field, focused on a near or mid object, or are looking at a very wide angle shot, with separated objects near and far, in a lot of blank space. Period....that's it.

A look that accentuates what our eyes naturally see, is what makes things stand out in space. With our eyes, only the object we focus on is in focus, things closer and further are out of focus. Changing that AMOUNT of out of focus is what optics can do (that our eyes cannot), depending on the lens aperture and focal length for what distance you are shooting. A 75mm puts things out of focus easier than a 24mm lens. It looks more "3D" to some. In Large Format, photographers play with movements to radically adjust the out of focus areas sometimes. And some call the look "rounded" or "3D."

To me, this looks kind of 3D. But does it to you?

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Old 1 Week Ago   #82
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There are experiments that will prove no manufacturer has more 3D to their lenses.

1. Take a photo with the "Leica 3d Look Lens", whatever that is. Compose an open area that has several objects of different sizes and distances. Focus on the close one, shoot wide open. Get another lens from another maker, with the same focal length and shoot at the same aperture. Compare. Other than some contrast, color rendition, coma, spherical and chromatic aberrations, and linear aberrations, they will look the same. I.E one will look sharper and more contrasty. Neither will show more of a 3D look, if you ask 10 people. (Like Hypnosis though, some will insist it works, and one "really looks 3D to me!)
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Old 1 Week Ago   #83
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Not sure I agree with you, Garrett. I have had two Summicron 35s, one of them the Summicron-M Version IV (which I currently own) and the other the ASPH. To my eye the ASPH gave more abrupt transition between in and out of focus (at the same aperture) and thus more of a 3D 'pop'. I think this was probably due to the fact that the lens was better corrected. In other words, in practical terms speed and focal length are not the only contributors to apparent DoF.
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Old 1 Week Ago   #84
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Quote:
Originally Posted by lawrence View Post
Not sure I agree with you, Garrett. I have had two Summicron 35s, one of them the Summicron-M Version IV (which I currently own) and the other the ASPH. To my eye the ASPH gave more abrupt transition between in and out of focus (at the same aperture) and thus more of a 3D 'pop'. I think this was probably due to the fact that the lens was better corrected. In other words, in practical terms speed and focal length are not the only contributors to apparent DoF.
"A more abrupt transition between in and out of focus?" So you are saying it has a shorter depth of field? At the same aperture? That's optically impossible. You'd have to prove it with identical photographs taken by the two lenses of a ruler or similar, showing your hypothesis.
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Old 1 Week Ago   #85
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I got a nice result yesterday


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Old 1 Week Ago   #86
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fully agree that various elements, specially lighting will be involved to make for a 3D impression and less the lens used. However I have been wondering if strong "field curverture" of a lens plays a role and can enhance 3D impression, this would be lens specific only.

does anyone see some weird focal plane going on here? and if so, does this enhance 3D impression?


Untitled
by andreas, on Flickr, Canon LTM f2/35mm, Sony A7, SAigon 2017

by "weird focal plane" I was referring to the left, also right top corner to look rather sharp while the area in the same distance in the middle of the frame more oof. If this is so I must say that it also may be due to my somewhat wobbly Leica M > Sony E helicoid adapter but I'd think that the strong field curverture of the lens plays a decisive role, chances are that here it's a mixture of both.
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Old 1 Week Ago   #87
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Quote:
Originally Posted by Rob-F View Post
The 3D element seems always to be very close to the camera, and either fully or partially side-lighted. The most prominent ones seem to have strong highlights. I'm not sure yet about the "micro-contrast" claims.
Yes, and I'd add colour contrast to that list; meaning subject vs. background. And 50mm and longer and f/2 and wider seems to help...

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Old 1 Week Ago   #88
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Quote:
Originally Posted by lawrence View Post
Not sure I agree with you, Garrett. I have had two Summicron 35s, one of them the Summicron-M Version IV (which I currently own) and the other the ASPH. To my eye the ASPH gave more abrupt transition between in and out of focus (at the same aperture) and thus more of a 3D 'pop'. I think this was probably due to the fact that the lens was better corrected. In other words, in practical terms speed and focal length are not the only contributors to apparent DoF.
Of course you're right. The particular lenses' field curvature is one of the contributors that have to be mentioned.
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Old 6 Days Ago   #89
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Quote:
Originally Posted by goamules View Post
"A more abrupt transition between in and out of focus?" So you are saying it has a shorter depth of field? At the same aperture? That's optically impossible. You'd have to prove it with identical photographs taken by the two lenses of a ruler or similar, showing your hypothesis.
Depth of Field is not an absolute because a lens is actually only sharp at a single distance, DoF being 'what you can get away with'. In other words, it's a zone of what appears to be sharp focus and is dependent on a number of factors including viewing distance, size of enlargement and so on.

In order to calculate the DoF you first need to specify the 'circle of confusion' that you're going to use, which is in itself somewhat arbitrary. I discovered this to my cost many years ago when using at Mamiya 645, religiously sticking to the DoF markings on the lens and then discovering that my negatives weren't as sharp as I'd expected.

With respect, I don't have to spend my time proving this with a ruler since I've already proved it to my own satisfaction in the field.
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Old 6 Days Ago   #90
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I wonder whether anyone can show an identical scene shot with two different lenses of the same focal length, one with the "3D look" and the other without? I doubt it.
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Old 6 Days Ago   #91
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Quote:
Originally Posted by stephen.w View Post
I wonder whether anyone can show an identical scene shot with two different lenses of the same focal length, one with the "3D look" and the other without? I doubt it.
I could, but I have the belly feeling that you're goamules' sock puppet, hence: no, I won't show you anything.
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Old 6 Days Ago   #92
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Originally Posted by radi(c)al_cam View Post
I could, but I have the belly feeling that you're goamules' sock puppet, hence: no, I won't show you anything.
Not only that: there are those of us who take pictures, and those of us who test lenses... I normally do the latter only when I'm paid to do so.

Cheers,

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Old 6 Days Ago   #93
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I could,
You can't.
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Old 6 Days Ago   #94
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Quote:
Originally Posted by radi(c)al_cam View Post
Of course you're right. The particular lenses' field curvature is one of the contributors that have to be mentioned.
Quote:
Originally Posted by tunalegs View Post
You can't.
errrrm, vide supra.

edit: I just realised that kuuan said quite the same as me ^^
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Old 6 Days Ago   #95
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Quote:
Originally Posted by radi(c)al_cam View Post
edit: I just realised that kuuan said quite the same as me ^^
right, conincidentally just one hour earlier..
said same here: http://www.rangefinderforum.com/foru...2&postcount=41 but more than anything it's an acquired feeling.
I am curious if the above photo of the kids could be a sample
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Old 6 Days Ago   #96
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Quote:
Originally Posted by stephen.w View Post
I wonder whether anyone can show an identical scene shot with two different lenses of the same focal length, one with the "3D look" and the other without? I doubt it.
Exactly what I was saying. When someone brings up a hypothetical question about a unproven and mystical lens trait, if you recommend an experiment to prove your point (or disprove the fallacies), you are told to shut up and go take photos. By people that spend most days on this forum attacking and criticizing everyone else. No offence intended Lawrence, I didn't mean "you must prove this." I just meant if "one wanted to, they'd have to do this." Otherwise, it's subjective "beliefs" not based on any fact.
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Old 6 Days Ago   #97
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Quote:
Originally Posted by stephen.w View Post
I wonder whether anyone can show an identical scene shot with two different lenses of the same focal length, one with the "3D look" and the other without? I doubt it.
Member x-ray posted this link on the first page. I can kinda see what he's talking about. At least it's an interesting comparison, even if you don't necessarily see the Cooke as having more 3d or not.

https://vimeo.com/90168989
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Old 6 Days Ago   #98
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Quote:
Originally Posted by goamules View Post
Quote:
Originally Posted by stephen.w View Post
I wonder whether anyone can show an identical scene shot with two different lenses of the same focal length, one with the "3D look" and the other without? I doubt it.
Exactly what I was saying. When someone brings up a hypothetical question about a unproven and mystical lens trait, if you recommend an experiment to prove your point (or disprove the fallacies), you are told to shut up and go take photos. By people that spend most days on this forum attacking and criticizing everyone else. []
belly feeling

Quote:
Originally Posted by kuuan View Post
right, conincidentally just one hour earlier..
said same here: http://www.rangefinderforum.com/foru...2&postcount=41 but more than anything it's an acquired feeling.
I am curious if the above photo of the kids could be a sample
IMHO, yes.

Additionally: Your picture (resp. this particular field curvature) IMHO shows pretty accurately how many biological life forms see/watch their environment: we focus on something (centre) but at the same time we must always see/watch whether or not a (more dangerous than us) predator is approaching from the side certainly, a biologist/zoologist could explain much better what I mean.
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Old 6 Days Ago   #99
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So I wonder, is anybody going to get around to testing their lenses?
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Old 6 Days Ago   #100
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Quote:
Originally Posted by Maximilian View Post
Member x-ray posted this link on the first page. I can kinda see what he's talking about. At least it's an interesting comparison, even if you don't necessarily see the Cooke as having more 3d or not.

https://vimeo.com/90168989
Thanks, I had missed that. I agree it is an interesting comparison.

I know next to nothing about cine lenses, but in the stills comparison at 04:20 onwards the lenses seem to have different native colour temperatures (with the Cooke being the cooler), and the Leica image seems to be slightly over exposed (compare the background light in centre of the frame), and the Leica has a more pronounced out-of-focus transition of the two. The Leica also seems to show some barrel distortion. Maybe all this confers a "3d look" on the Cooke lens, I don't know
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Old 6 Days Ago   #101
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Quote:
Originally Posted by radi(c)al_cam View Post
I could, but I have the belly feeling that you're goamules' sock puppet, hence: no, I won't show you anything.
Apologies, I only read the original post before I did so myself. I would be genuinely interested in seeing your comparisons.
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Old 6 Days Ago   #102
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Quote:
Originally Posted by goamules View Post
No offence intended Lawrence, I didn't mean "you must prove this." I just meant if "one wanted to, they'd have to do this." Otherwise, it's subjective "beliefs" not based on any fact.
It's based on my own observation, which is enough of a fact for me. If you want to believe 'alternative facts', that's fine too
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Old 5 Days Ago   #103
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curiosity made me go out and take fast and dirty ( handheld, A mode, auto ISO ) comparison shots
an old manual prime and 28-70mm kit zoom on Sony A7 set at the same focal lenghts, all @f4.

e.g.:

Untitled by kuuan's lens tests, on Flickr

Untitled by kuuan's lens tests, on Flickr

the question certainly would deserve a better job, please pardon me.
nevertheless I am curious if anyone can see a difference regarding 3D impression ( if there is any at all..)

14 pairs of pics: https://www.flickr.com/photos/kuuans...h/33908018233/
( for now view of EXIFs is disabled, as if one couldn't tell which is which.., shall make that available again soon )
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Old 5 Days Ago   #104
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so subjective, but the medium format Pentax 67 has ALWAYS caught my attention with its images

... even though I haven't owned one. Even an average fotog wouldn't have much trouble shooting some 3D-esque images with this get up
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Old 5 Days Ago   #105
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I personally don't believe that the "3D effect" is lens dependent. This image is from a Sony A6500 with a rather mundane Minolta Rokkor-X 2.0/45 kit lens:

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