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> I used the 1x camera, which is 26mm at f/1.5 I find this way of describing the iPhone cameras frustratingly misleading. It's not the author's fault; Apple do

by wyager 3y ago

> I used the 1x camera, which is 26mm at f/1.5 I find this way of describing the iPhone cameras frustratingly misleading. It's not the author's fault; Apple does it in their official specs. The "26mm" rating is "equivalent", meaning "this looks like a 26mm lens on a 35mm film camera". It basically tells you the FOV angle. The "f/1.5" rating is not equivalent. It's very dishonest to mix and match equivalent and non-equivalent specs, because it makes the lens sound a lot better than it is to non-expert readers. If they were being honest, the equivalent aperture would be a lot smaller, like f/16 or something. Every other camera mfg I am aware of will consistently use equivalent or non-equivalent for all specs, and make it clear which they are using. For example, most mirrorless camera lenses are spec'd non-equivalently, meaning that a "26mm f/1.5" means "if you put this lens on a 35mm camera and extrapolated the output to cover the whole sensor, that's what you would get". To understand what it will look like on a different sensor, you multiply 26 and 1.5 by the crop factor. In Apple's case, it's actually impossible to tell what the image will look like from the specs without looking up the crop factor, which of course they don't advertise front and center like they do this misleading tuple of specs. In general, lenses with smaller f/N aperture values tend to be better and more expensive (because they have a larger aperture, let in more light, narrower depth of field), so if you don't mind misleading customers, you just pick the smallest denominator you can get away with.

doodlesdev 3y ago
Every time people tell me iPhone cameras are getting as good as dedicated DSLR/mirrorless, I always point this out to them. F/16 is absolutely unusable for certain types of photography (although quite perfect for landscape), and even worse with such a small sensor with that big of a crop factor (3.5x) [0]. I personally use a f1.8 35 mm on an APS-C sensor for hobby photography and I still feel the sensor is too small for portrait photography or low light, but then I'm also kind of a weirdo since I still use film cameras once in a while (can't afford a full-frame lol, so I use it for portraits). [0]: https://www.dpreview.com/articles/6110937480 https://www.dpreview.com/articles/6110937480
- foldr 3y ago
  I don’t personally care for shallow depth of field (it’s become a cliche at this point), but the best phone cameras do a pretty good job of faking it. It’s not yet perfect, but it’s only going to get better. I also like that I can precisely adjust the amount of background blur in post.
karashi 3y ago
Camera manufacturers do the same misleading marketing too right? Here’s a video of someone complaining about it. https://youtu.be/6Im4W_9blhY?t=7m28s https://youtu.be/6Im4W_9blhY?t=7m28s That said, at least with stand-alone camera manufacturers you can usually work out what the real specs should be if you’re in the know.
musictubes 3y ago
I hate hate hate “equivalent aperture” specs. I don’t mind the FOV being equated to 35mm sensor size but give me the actual Fstop please. Back in the day I shot formats from 8x10 down to 16mm. Nobody ever tried to normalize DOF between formats by talking about fstops until digital photography. Trying to normalize DOF across formats only obscures and confuses what is actually going on optically. No particular fstop (ratio between focal length and physical aperture) has a unique look and yet that is what people that demand equivalent fstops assume and demand. For exposure purposes, f1.5 is the accurate and most important spec for that lens. All mirrorless camera lenses are specced accurately with focal length and fstop. Perhaps some of the marketing is done with 35mm “equivalent” specs but I’ve never seen a lens that had anything but the actual measurements on them. I’m not sure why people are still referring to 35mm focal lengths when talking about FOV in any case. Nobody is comparing the lens on an iPhone with one on a camera with a 35mm sized sensor. Certainly nobody will use the iPhone lens on another camera. The main sensor on an iPhone is larger than most phone cameras but still close enough that touting the f1.5 fstop does indeed mean that it lets in more light, has a larger aperture, and has a narrower DOF than many other phone cameras. The vast majority of iPhone users have never shot with 35mm cameras and so wouldn’t have any idea what you’re talking about when it comes to 35mm DOF. I wish companies would ditch the 35mm normalized specs altogether.
- wyager 3y ago
  > For exposure purposes, f1.5 is the accurate and most important spec for that lens. This is a very common misunderstanding. To whatever extent the camera "looks like" it's using a 35mm-format f/1.5 lens from an exposure standpoint, it's only because the sensor gain is turned way up to compensate. As a result, SNR is worse, so it's like you took a darker exposure on a better camera and then cranked it up in post.
  - oktoberpaard 3y ago
    At a given shutter speed, the sensor gain is exactly as high as you would expect it to be at f/1.5. It’s just that with the much smaller surface area of the sensor, the signal-to-noise ratio is way worse.
chipsa 3y ago
The f/1.5 is an actual rating. It's the ratio between the focal length and the diameter of the pupil. It's important for shutter speeds, and relative performance in low light (before all the computational duckery). I can compare roughly a phone camera that's at f/1.5 vs a phone camera that's at f/2. Making a low f/number lens is more difficult than a high f/number lens, regardless of actual focal length. And I've got a non-35mm mirrorless camera. All the lens I've got are marked with the true focal length and true f/number, not some "equivalent". My iPhone camera photos' metadata show the focal length, both true and "35mm equivalent".
- wyager 3y ago
  > The f/1.5 is an actual rating. You're not disagreeing with my actual argument, which is just "they should use the equivalent ratings for both focal length and f-stop". If you prefer physically-based specs, you should be demanding that they also say the focal length is 7mm or whatever. > It's important for shutter speeds, and relative performance in low light It's completely useless for determining low-light perf without knowing the crop factor. > I can compare roughly a phone camera that's at f/1.5 vs a phone camera that's at f/2 Not without knowing the crop factor. You're falling for the marketing.
ulfw 3y ago
The f is not an equivalency number. It's the actual f stop number. F number is the ratio of the lens focal length to the diameter of the entrance pupil and is independent of the size of said lens. The depth of field on the other hand does depend on the size of the lens (or hence the size of the sensor the lens focuses it's incoming light on). Let's take an 18mm F/2 lens on a Micro-Fourthirds camera. Those have a 2x ratio of sensor size compared to a full-frame sensor. So this 18mm lens would be an (2x18=36mm "equivalent") full-frame lens, meaning the perspective of said 18mm would be the same perspective a standard 35-36mm full frame lense would have. This 18mm F/2 lens would be F/2.0 based on the amount of light it lets in. That's the ratio of said lenses focal length to it's entrance pupil. Only in terms of "how the background will blur" we multiply this by 2 to show what the visual effect of this would be. So really the best way of saying it would be "hey this is an 18mm/F2 Micro Four Thirds lens (36mm, F2/F4 equivalent). Personal opinion: Even better if we used a different acronym for depth of field, say d or doF or something. Then we could say "36mm f2.0 DoF4.0"-equivalent lens. So in the iPhone 14PM main camera case we'd call it a "28mm f1.78 DoF8.1"-equivalent as it has an about 4.6x sensor size crop factor from full frame.
ulfw 3y ago
With a crop factor of 4.6 the depth of field equivalent would be around f8 actually for the larger 14 Pro / 14 Pro Max sensor. (and f1.78 for actual f-stop light performance) When you get close enough you can actually take proper bokeh producing shots. It's actually becoming hard to be fixed aperture as some closer shots would require a higher f-stop number already to be properly in focus.

by wyager 3y ago

doodlesdev 3y ago

Every time people tell me iPhone cameras are getting as good as dedicated DSLR/mirrorless, I always point this out to them. F/16 is absolutely unusable for certain types of photography (although quite perfect for landscape), and even worse with such a small sensor with that big of a crop factor (3.5x) [0]. I personally use a f1.8 35 mm on an APS-C sensor for hobby photography and I still feel the sensor is too small for portrait photography or low light, but then I'm also kind of a weirdo since I still use film cameras once in a while (can't afford a full-frame lol, so I use it for portraits). [0]: https://www.dpreview.com/articles/6110937480 https://www.dpreview.com/articles/6110937480

foldr 3y ago
I don’t personally care for shallow depth of field (it’s become a cliche at this point), but the best phone cameras do a pretty good job of faking it. It’s not yet perfect, but it’s only going to get better. I also like that I can precisely adjust the amount of background blur in post.

karashi 3y ago

Camera manufacturers do the same misleading marketing too right? Here’s a video of someone complaining about it. https://youtu.be/6Im4W_9blhY?t=7m28s https://youtu.be/6Im4W_9blhY?t=7m28s That said, at least with stand-alone camera manufacturers you can usually work out what the real specs should be if you’re in the know.

musictubes 3y ago

I hate hate hate “equivalent aperture” specs. I don’t mind the FOV being equated to 35mm sensor size but give me the actual Fstop please. Back in the day I shot formats from 8x10 down to 16mm. Nobody ever tried to normalize DOF between formats by talking about fstops until digital photography. Trying to normalize DOF across formats only obscures and confuses what is actually going on optically. No particular fstop (ratio between focal length and physical aperture) has a unique look and yet that is what people that demand equivalent fstops assume and demand. For exposure purposes, f1.5 is the accurate and most important spec for that lens. All mirrorless camera lenses are specced accurately with focal length and fstop. Perhaps some of the marketing is done with 35mm “equivalent” specs but I’ve never seen a lens that had anything but the actual measurements on them. I’m not sure why people are still referring to 35mm focal lengths when talking about FOV in any case. Nobody is comparing the lens on an iPhone with one on a camera with a 35mm sized sensor. Certainly nobody will use the iPhone lens on another camera. The main sensor on an iPhone is larger than most phone cameras but still close enough that touting the f1.5 fstop does indeed mean that it lets in more light, has a larger aperture, and has a narrower DOF than many other phone cameras. The vast majority of iPhone users have never shot with 35mm cameras and so wouldn’t have any idea what you’re talking about when it comes to 35mm DOF. I wish companies would ditch the 35mm normalized specs altogether.

wyager 3y ago
> For exposure purposes, f1.5 is the accurate and most important spec for that lens. This is a very common misunderstanding. To whatever extent the camera "looks like" it's using a 35mm-format f/1.5 lens from an exposure standpoint, it's only because the sensor gain is turned way up to compensate. As a result, SNR is worse, so it's like you took a darker exposure on a better camera and then cranked it up in post.
- oktoberpaard 3y ago
  At a given shutter speed, the sensor gain is exactly as high as you would expect it to be at f/1.5. It’s just that with the much smaller surface area of the sensor, the signal-to-noise ratio is way worse.

chipsa 3y ago

The f/1.5 is an actual rating. It's the ratio between the focal length and the diameter of the pupil. It's important for shutter speeds, and relative performance in low light (before all the computational duckery). I can compare roughly a phone camera that's at f/1.5 vs a phone camera that's at f/2. Making a low f/number lens is more difficult than a high f/number lens, regardless of actual focal length. And I've got a non-35mm mirrorless camera. All the lens I've got are marked with the true focal length and true f/number, not some "equivalent". My iPhone camera photos' metadata show the focal length, both true and "35mm equivalent".

wyager 3y ago
> The f/1.5 is an actual rating. You're not disagreeing with my actual argument, which is just "they should use the equivalent ratings for both focal length and f-stop". If you prefer physically-based specs, you should be demanding that they also say the focal length is 7mm or whatever. > It's important for shutter speeds, and relative performance in low light It's completely useless for determining low-light perf without knowing the crop factor. > I can compare roughly a phone camera that's at f/1.5 vs a phone camera that's at f/2 Not without knowing the crop factor. You're falling for the marketing.

ulfw 3y ago

The f is not an equivalency number. It's the actual f stop number. F number is the ratio of the lens focal length to the diameter of the entrance pupil and is independent of the size of said lens. The depth of field on the other hand does depend on the size of the lens (or hence the size of the sensor the lens focuses it's incoming light on). Let's take an 18mm F/2 lens on a Micro-Fourthirds camera. Those have a 2x ratio of sensor size compared to a full-frame sensor. So this 18mm lens would be an (2x18=36mm "equivalent") full-frame lens, meaning the perspective of said 18mm would be the same perspective a standard 35-36mm full frame lense would have. This 18mm F/2 lens would be F/2.0 based on the amount of light it lets in. That's the ratio of said lenses focal length to it's entrance pupil. Only in terms of "how the background will blur" we multiply this by 2 to show what the visual effect of this would be. So really the best way of saying it would be "hey this is an 18mm/F2 Micro Four Thirds lens (36mm, F2/F4 equivalent). Personal opinion: Even better if we used a different acronym for depth of field, say d or doF or something. Then we could say "36mm f2.0 DoF4.0"-equivalent lens. So in the iPhone 14PM main camera case we'd call it a "28mm f1.78 DoF8.1"-equivalent as it has an about 4.6x sensor size crop factor from full frame.

ulfw 3y ago

With a crop factor of 4.6 the depth of field equivalent would be around f8 actually for the larger 14 Pro / 14 Pro Max sensor. (and f1.78 for actual f-stop light performance) When you get close enough you can actually take proper bokeh producing shots. It's actually becoming hard to be fixed aperture as some closer shots would require a higher f-stop number already to be properly in focus.