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iPhone 13 Pro Is the f/2.8 on the telephoto really a problem?

M

matejphoto

macrumors newbie
Original poster
Oct 17, 2011
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I saw many people pointing out that the telephoto lens on the iPhone 13 Pro has a disappointing f/2.8 lens. They also like to point out that the iPhone 12 has f/2.0 (Pro) and f/2.2 (Pro Max).

Few things that I think are important to point out:
1.) The aperture value is almost useless unless you know the size of the sensor. As far as I know, nobody outside apple knows the sensor size behind the telephoto on the iPhone 13 Pro.
Extreme example for illustration: Imagine it is a 77mm lens with a full frame sensor and f/2.8. That would give you amazing image quality and lots of bokeh. So until we know the sensor size the f/2.8 is meaningless.

2.) Since apple did not point any increase in sensor size, let's assume that the sensor size is the same as in iPhone 12 PRO.
But since the equivalent focal length changed, I think the better indicator of overall image quality is the size of the entrance pupil (bigger = more light).
Entrance pupil iPhone 12 PRO: 26.0
Entrance pupil iPhone 12 PRO MAX: 29.5
Entrance pupil iPhone 13 PRO: 27.5
So the iPhone 13 PRO is not a big improvement but on par with previous models.
Again an extreme example: Canon 600mm is only f/4, but has a massive entrance pupil and amazing image quality.

iPhone 13 Pro - Entrance Pupil Calculations.png
 
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Thanks! I will keep an eye on those. To me it seems that even the big reviewers don’t pay enough attention to the telephoto camera. I personally find it incredibly useful to take pictures of people.
 
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matejphoto said:

Is the f/2.8 on the telephoto really a problem?​

Click to expand...
In good light, hardly. In worse light, it'll be even worse (noisier or, in the worst case, getting completely black) than the UW lens on the iPhone 11 (incl. the Pro models), iPhone 12 (incl. Pro) and the iPhone 13 and the iPhone 13 Mini.

Back in the 7+ days (that particular model still didn't have IS with the tele lens, resulting in possible blurry footage in anything than very good light), the problem was so severe that, during shooting, you could never know when the phone switched back to using the main camera and digital cropping. And you couldn't disable this even when shooting on a tripod. This has ruined a LOT of my 4k shots :( Fortunately, iPhones' tele lens received IS with the X.

EDIT: added the 7+ paragraph.
 
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I think that is assuming that the sensor size will stay the same.
From the past, what is the most reliable source to find out sensor sizes? I only saw them listed on DXOmark reviews, I wonder where they got them.
 
> Is the f/2.8 on the telephoto really a problem?

No. The #1 ranked Smartphone on dxomark.com has a tele lense with 3.5 aperture. It's 90mm comparatively, but that is not that much more of a zoom, honestly.

2.8 is kinda a default in the professional world. Sure not for fixed with lenses, but with zooms and actual tele lenses.
 
It's a telephoto lens. It should prioritize genuine focal lengths over speed and low light. That said, yes, you really can't just compare aperture like it is 1:1 with other lenses or previous iPhones even. The sensor, resolutions, lens itself - all change performance.
 
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I also think the addition of night mode to the telephoto should help compensate for any loss of low light capabilities; my guess is that it'll actually exceed the 12 Pro telephoto.
 
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Nikhil72 said:
I also think the addition of night mode to the telephoto should help compensate for any loss of low light capabilities; my guess is that it'll actually exceed the 12 Pro telephoto.
Click to expand...
This won't help daytime for example video performance, though.
 
That’s the comment I was about to make. If the telephoto has been night moded(new word) then the potential graininess in low light shots will Be compensated, to what degree, we shall see
 
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F/ is short for focal length divided by aperture. If you increase the focal length of the lens without changing the aperture, f/ increases, by definition. That’s not disappointing, it’s just math.

The only way to increase the focal length and keep f/ the same is to increase the aperture. But integrating a big-aperture lens into a cellphone would be problematic.

In engineering, there are trade offs to everything.
 
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I am super curious how this is going to work.
Since the iPhone X if you select 2x and the light is low, the phone would automatically switch to the wide lens and crop. The idea was that if light is low, the wide sensor is that much better that a crop from wide lens will be better than the 2x lens. I absolutely despise this feature, it would be totally ok if the phone would alert me (e.g. simple turn the 2x icon red or yellow when it does this). Because if it is giving me the crop, I might as well shoot with the wide lens.

Back to iPhone 13 pro: if it has night mode I wonder it the above trick (feature) is abolished.
It would be super weird if it did this:
Good light: 77mm lens
Medium light: 26mm lens with crop
Poor light: 77mm lens with night mode

I hope the crop feature is gone. Maybe it is so, since it now has to crop 3x.
 
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matejphoto said:
I am super curious how this is going to work.
Since the iPhone X if you select 2x and the light is low, the phone would automatically switch to the wide lens and crop. The idea was that if light is low, the wide sensor is that much better that a crop from wide lens will be better than the 2x lens. I absolutely despise this feature, it would be totally ok if the phone would alert me (e.g. simple turn the 2x icon red or yellow when it does this). Because if it is giving me the crop, I might as well shoot with the wide lens.

Back to iPhone 13 pro: if it has night mode I wonder it the above trick (feature) is abolished.
It would be super weird if it did this:
Good light: 77mm lens
Medium light: 26mm lens with crop
Poor light: 77mm lens with night mode

I hope the crop feature is gone. Maybe it is so, since it now has to crop 3x.
Click to expand...
BTW, this auto-cropping wasn't introed by the X but by the 7+ (the very first phone with a Tele lens). There, the problem was REALLY bad. A lot of my 4k videos I shot on the 7+ in good light(!!!) turned out to only have 1080p real resolution when I switched to the Tele lens. The X was already far better in this respect - but, unfortunately, the auto-cropping remained in bad light.

There have been several threads on this here at MR; IIRC the author of Filmic Pro did elaborate on this problem quite a lot and also stated he'd found a solution to it. Too bad I prefer shooting using the stock Camera app and try to avoid 3rd party apps for mission-critical work (event videos I can't do again if the app crashes).
 
matejphoto said:
I saw many people pointing out that the telephoto lens on the iPhone 13 Pro has a disappointing f/2.8 lens. They also like to point out that the iPhone 12 has f/2.0 (Pro) and f/2.2 (Pro Max).

Few things that I think are important to point out:
1.) The aperture value is almost useless unless you know the size of the sensor. As far as I know, nobody outside apple knows the sensor size behind the telephoto on the iPhone 13 Pro.
Extreme example for illustration: Imagine it is a 77mm lens with a full frame sensor and f/2.8. That would give you amazing image quality and lots of bokeh. So until we know the sensor size the f/2.8 is meaningless.

2.) Since apple did not point any increase in sensor size, let's assume that the sensor size is the same as in iPhone 12 PRO.
But since the equivalent focal length changed, I think the better indicator of overall image quality is the size of the entrance pupil (bigger = more light).
Entrance pupil iPhone 12 PRO: 26.0
Entrance pupil iPhone 12 PRO MAX: 29.5
Entrance pupil iPhone 13 PRO: 27.5
So the iPhone 13 PRO is not a big improvement but on par with previous models.
Again an extreme example: Canon 600mm is only f/4, but has a massive entrance pupil and amazing image quality.

View attachment 1836143
Click to expand...
I saw your post on this at DP Review. I had the same thought in that if the sensor size on the telephoto had changed, especially for the better, they would have mentioned it. Since they did not, seems like a safe assumption it’s the same size sensor as the 12 pro. I’m interested to see the comments on DP Review on this. They’ve got some real pro’s on that site…should be interesting. I can’t understand why the max aperture had decresed from f/2.2 to f/2.8 on the telephoto lens. Smaller aperture results in need for lower shutter speed (bad for moving subjects) and/or higher ISO (Grainer photos). 🧐

Perhaps Apple is setting the stage incentives to upgrade to the iPhone 14 pro next year (ie massive improvements to the telephoto lens: larger sensor, f/2.0 max aperture, sensor shift).
 
DSTOFEL said:
I saw your post on this at DP Review. I had the same thought in that if the sensor size on the telephoto had changed, especially for the better, they would have mentioned it. Since they did not, seems like a safe assumption it’s the same size sensor as the 12 pro. I’m interested to see the comments on DP Review on this. They’ve got some real pro’s on that site…should be interesting. I can’t understand why the max aperture had decresed from f/2.2 to f/2.8 on the telephoto lens. Smaller aperture results in need for lower shutter speed (bad for moving subjects) and/or higher ISO (Grainer photos). 🧐

Perhaps Apple is setting the stage incentives to upgrade to the iPhone 14 pro next year (ie massive improvements to the telephoto lens: larger sensor, f/2.0 max aperture, sensor shift).
Click to expand...
It's a longer lens, as your lens gets longer the size has to increase to maintain the same aperture. This is why all telephoto lenses are f2.8 and up. Apple made the decision to trade range for aperture, which is required by the laws of physics. In order to maintain the same aperture the lens would have to become much larger. Go look up a 300m f2.8 professional lens if you want an example of how large/wide those lens have to be at longer ranges.
 
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cap7ainclu7ch said:
It's a longer lens, as your lens gets longer the size has to increase to maintain the same aperture. This is why all telephoto lenses are f2.8 and up. Apple made the decision to trade range for aperture, which is required by the laws of physics. In order to maintain the same aperture the lens would have to become much larger. Go look up a 300m f2.8 professional lens if you want an example of how large/wide those lens have to be at longer ranges.
Click to expand...
77MM is not exactly long. And not “all“ telephoto lenses are f/2.8 and up:). For example, on my DSLR’s, I’ve got an 85mm f/1.4 and a 135mm f/2.0. But yes, who knows how large the iphone tele-lens would physically have had to be to maintain f/2.0 with the increase of the tele-lens from 58mm on the 12 pro to 77mm on the 13 pro.
 
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I doubt the sensor is much larger or more sensitive to make up for the aperture loss of the lens. If it is, Apple should communicate that. Anyway, I still think that anyone who's serious about photography should keep their 1-3 year old iPhone and use the upgrade money on a real digital camera instead.
 
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allenvanhellen said:
I doubt the sensor is much larger or more sensitive to make up for the aperture loss of the lens. If it is, Apple should communicate that. Anyway, I still think that anyone who's serious about photography should keep their 1-3 year old iPhone and use the upgrade money on a real digital camera instead.
Click to expand...

This is true, but having a device that takes near-high quality camera photos on you at all times is very helpful since lugging around a DSLR everywhere at all times is not really possible.
 
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DSTOFEL said:
77MM is not exactly long. And not “all“ telephoto lenses are f/2.8 and up:). For example, on my DSLR’s, I’ve got an 85mm f/1.4 and a 135mm f/2.0. But yes, who knows how large the iphone tele-lens would physically have had to be to maintain f/2.0 with the increase of the tele-lens from 58mm on the 12 pro to 77mm on the 13 pro.
Click to expand...
I didn't say it was long, I said it was longer. They are size restricted and these cameras are already much larger in size compared to the previous models. Judging by the new size I'd imagine the glass quality is going to be substantially better and we will be seeing nicer images beyond sensor improvements.
 
I hear this argument pretty often: save your money and buy a real camera.
But I already own lots of nice cameras with big sensors and nice lenses. A phone (iPhone or android) just can’t be beat for convenience. My family has been annoyed countless times with me taking too long to take pictures during family activities. It definitely slows you down to fish a camera out of the bag, change lenses,….
I think I would be willing to pay $2-3k for a truly pro phone: make it thinker, put even a bigger sensor in it and let me customize everything I want.
 
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