Optical zoom 4k filming expert technical advice needed - 15 Pro Max

[thegr8wendt]

I've read a bit about the sensors that each camera uses during photo taking, but I'm looking for some information about the cameras/sensors that are used during 4k video filming.

"Each lens on the iPhone 15 is backed by its own sensor, so an iPhone 15 Pro includes four separate cameras, including the front-facing one. Only the main camera includes a 48MP sensor, so for 48MP images, you need to be shooting at 1x zoom. The 0.5x ultrawide and 3x or 5x telephoto (on the Pro and Pro Max models) cameras use 12MP sensors."

"The ultrawide (0.5x) or telephoto (3x/5x) cameras each capture images optically, where each pixel corresponds to the area perceived in the field of view – if you don't tweak the zoom. If you choose an arbitrary zoom level between those ranges, such as by pinching two fingers on the screen, the camera zooms digitally and interpolates how the pixels appear based on that field of view, which can introduce softness or artifacts."

I'm only interested in using Optical zoom. The line highlighted in bold above is of great concern. Which camera/sensor/megapixels are used in these scenarios:

1. Start filming in 4k at 1x zoom > place finger on magnification bar so zoom wheel pops up > slowly zoom from 1x to 5x (from near to far with gradual increase)
2. Start filming in 4k at 1x zoom > tap zoom to 3x > tap zoom to 5x (from near to far with step increases)

Without using ProRes or Log Format - I'm looking for the best settings / best practices for zooming near to far while maintaining the best possible resolution.

Thanks in advance

 

[coolguy4747]

I just looked on my 15 Pro and saw how it works for 3x rather than 5x, but it pretty much has to be the same conceptually on the Pro Max:

1) main camera for 1x-4.9x, then it will switch to the telephoto camera for 5x
2) main camera for 1x-3x and 3x-4.9x, and it will switch to the telephoto camera at the last moment for 5x

 

[thegr8wendt]

I just looked on my 15 Pro and saw how it works for 3x rather than 5x, but it pretty much has to be the same conceptually on the Pro Max:

1) main camera for 1x-4.9x, then it will switch to the telephoto camera for 5x
2) main camera for 1x-3x and 3x-4.9x, and it will switch to the telephoto camera at the last moment for 5x

Thanks for the reply, but I have to wonder if you even read the italic paragraphs above? Your reply makes little to no sense. Why would the engineers reserve a dedicated lens for only .1 out of 5.0 zoom?

 

[coolguy4747]

Yes I read the entire post, thanks. The dedicated lens is for exactly that; dedicated "5x" shooting. My reply makes perfect sense if you understand how a fixed lens works. How do you expect a telephoto lens to show wider angle view than it is capable of showing?

 

[iStorm]

Lighting conditions can play a big factor in which camera/lens is used. The stock camera app will choose whatever it thinks will give you the best results. For example, if shooting 1x indoors or in a poorly lit area, it could actually be doing a 2x digital zoom from the ultra wide (0.5x) camera because that one lets more light in. Same when shooting in 3x/5x. It could actually be a 3x or 5x digital zoom from the 1x camera (and in rare cases, a 6x or 10x digital zoom from the ultra wide 0.5x camera).

The stock camera app doesn't give you much control of which camera/lens is used. If you want to be in control of which camera is used, you'll need to use a 3rd party app. Halide is one of the popular ones.

 

[thegr8wendt]

Yes I read the entire post, thanks. The dedicated lens is for exactly that; dedicated "5x" shooting. My reply makes perfect sense if you understand how a fixed lens works. How do you expect a telephoto lens to show wider angle view than it is capable of showing?

Aside from toggling on/off the Macro wide angle lens, why would anyone want to use a 12mp sensor over a 48mp sensor for .1 extra magnification?

"for 48MP images, you need to be shooting at 1x zoom. The 0.5x ultrawide and 3x or 5x telephoto (on the Pro and Pro Max models) cameras use 12MP sensors." "If you choose an arbitrary zoom level between those ranges, such as by pinching two fingers on the screen, the camera zooms digitally".

While I'd like to believe your reply is true, it's not based on any technical data.

 

[thegr8wendt]

Lighting conditions can play a big factor in which camera/lens is used. The stock camera app will choose whatever it thinks will give you the best results. For example, if shooting 1x indoors or in a poorly lit area, it could actually be doing a 2x digital zoom from the ultra wide (0.5x) camera because that one lets more light in. Same when shooting in 3x/5x. It could actually be a 3x or 5x digital zoom from the 1x camera (and in rare cases, a 6x or 10x digital zoom from the ultra wide 0.5x camera).

The stock camera app doesn't give you much control of which camera/lens is used. If you want to be in control of which camera is used, you'll need to use a 3rd party app. Halide is one of the popular ones.

Again - Without using ProRes or Log Format - I'm looking for the best settings / best practices for zooming near to far while maintaining the best possible resolution.

 

[coolguy4747]

While I'd like to believe your reply is true, it's not based on any technical data.

It is based on me recording a video starting at 1x and pinch zooming to 3x (max "optical zoom" on my phone) followed by me recording a video starting at 1x and zooming by tapping on 2x and 3x, and seeing the cameras change during recording

View attachment 2349055

Again - Without using ProRes or Log Format - I'm looking for the best settings / best practices for zooming near to far while maintaining the best possible resolution.

I don't zoom during videos so I never bothered to check settings, but there you go. With that enabled, presumably it will stay with whatever camera you start with (which cannot be the telephoto camera if you are starting wider than 5x)

 

[IngoX]

why would anyone want to use a 12mp sensor over a 48mp sensor for .1 extra magnification?

With 4.9x zoom you are using a cropped view of the 48 MP sensor, probably less than 12 MP, and each pixel is very small with drawbacks such as more sensitive to noise in low light. Add some interpolation to that and it is probably the zoom setting where you will get the lowest picture quality. Go up to 5x zoom and you use the telefoto lens with 12 MP sensor where each pixel is slightly larger and better.

 

[thegr8wendt]

With 4.9x zoom you are using a cropped view of the 48 MP sensor, probably less than 12 MP, and each pixel is very small with drawbacks such as more sensitive to noise in low light. Add some interpolation to that and it is probably the zoom setting where you will get the lowest picture quality. Go up to 5x zoom and you use the telefoto lens with 12 MP sensor where each pixel is slightly larger and better.

That makes sense. In the scenario I presented; zooming near to far, do you know which method will retain the highest resolution?

1. Start filming in 4k at 1x zoom > place finger on magnification bar so zoom wheel pops up > slowly zoom from 1x to 5x (from near to far with gradual increase)
2. Start filming in 4k at 1x zoom > tap zoom to 3x > tap zoom to 5x (from near to far with step increases)

Thanks

 

[coolguy4747]

They are the same as each other. They are doing the same video processing for any given "zoom," except one is automatically shifting between set intervals and the other is manually adjusted.

 

[thegr8wendt]

They are the same as each other. They are doing the same video processing for any given "zoom," except one is automatically shifting between set intervals and the other is manually adjusted.

While I appreciate you bumping this thread, you've already admitted to speculating this. If you know of a document or publication that supports your statement I'd love to read it.

But according to this publication, what you are saying is not true, because "The ultrawide (0.5x) or telephoto (3x/5x) cameras each capture images optically, where each pixel corresponds to the area perceived in the field of view – if you don't tweak the zoom. If you choose an arbitrary zoom level between those ranges, such as by pinching two fingers on the screen, the camera zooms digitally and interpolates how the pixels appear based on that field of view, which can introduce softness or artifacts."

 

[coolguy4747]

What? I'm not sure how that contradicts what I said.

.5x, 1x, and 3x Pro/5x Pro Max will give you the best detail. Anything between any of those intervals is digital zoom/interpolation as described in your quote. That section is also about still photos, not video. There's a lot more computational stuff going on to try to improve photos than there is for video.

You might be missing the "if you don't tweak the zoom" part and focusing on the "arbitrary zoom level" part, because you seem to be thinking this article is implying that there is a difference between zooming by pinching and zooming by tapping on different zoom values. There's not, in terms of image quality. Once again, I observed this from personal experience. Pinching from 1x to 2x is exactly the same as starting at 1x and tapping on 2x.

I highly doubt there is any "document or publication," aside from maybe internal confidential Apple product specs, that talk about this. If there is you would probably have found it, assuming you looked for it.

 

[coolguy4747]

I'm really trying to help you get to your answer. If I'm clearly misunderstanding something you're saying, can you spell out for me exactly what I'm saying that's incorrect? Everything I've said is from first person testing of the exact scenarios you're asking about.

 

[iStorm]

All the posts above are correct. I'm not exactly sure what you're asking or disagreeing with.

The camera lenses don't move, there's not an optical zoom range like a traditional camera. It's either 0.5x, 1x, or 3x/5x if you want the photo or video to be captured natively/optically...that's it. All other numbers are a digital zoom or a crop. It doesn't matter whether you pinch to zoom, move the wheel, or tap the numbers since they all do the same thing in the end...a digital zoom/crop when going between or above any of the three steps. So if you want the best quality overall in a video, I would tap the numbers since they switch to that camera/optical lens much quicker than pinching or moving the wheel. That will minimize the time a digital zoom/crop is being done.

 

[thegr8wendt]

All the posts above are correct. I'm not exactly sure what you're asking or disagreeing with.

So if you want the best quality overall in a video, I would tap the numbers since they switch to that camera/optical lens much quicker than pinching or moving the wheel. That will minimize the time a digital zoom/crop is being done.

Thanks for the reply, but actually some of the other responses are not correct. As you stated; Option 1 appears to be using digital zoom, while option 2 tends to lean towards optical zoom. Of course I understand there will be exceptions in different light situations.

 

[coolguy4747]

Thanks for the reply, but actually some of the other responses are not correct. As you stated; Option 1 appears to be using digital zoom, while option 2 tends to lean towards optical zoom. Of course I understand there will be exceptions in different light situations.

That's not what iStorm stated. We both stated that they are exactly the same as each other for any given "x" magnification. What iStorm said is that option 2 moves more quickly between the different magnifications, whether digital or optical. As I said, .5x, 1x, and 3/5x are the ONLY magnifications that do not use digital zoom, whether pinching or tapping. Once again, any magnification between these values will be digital zoom, and thus compromised to some degree (but again, you can not zoom out from the 3/5x lens without switching lenses). Unless you enable the option you showed above forcing the phone to stick the lens you start with and only use digital zoom, pinching will switch lenses as soon as you cross the relevant "zoom."

 

[thegr8wendt]

That's not what iStorm stated. We both stated that they are exactly the same as each other for any given "x" magnification. What iStorm said is that option 2 moves more quickly between the different magnifications, whether digital or optical. As I said, .5x, 1x, and 3/5x are the ONLY magnifications that do not use digital zoom, whether pinching or tapping. Once again, any magnification between these values will be digital zoom, and thus compromised to some degree (but again, you can not zoom out from the 3/5x lens without switching lenses). Unless you enable the option you showed above forcing the phone to stick the lens you start with and only use digital zoom, pinching will switch lenses as soon as you cross the relevant "zoom."

I asked which method Opt 1 or 2 is going to give me the best resolution (scrolling zoom, or tapping specific zoom) using optical zoom only.

You stated above "They are the same as each other. They are doing the same video processing for any given "zoom," except one is automatically shifting between set intervals and the other is manually adjusted." So if I were to use option 1 (scrolling zoom) it would in fact use digital zoom in between changing lenses until I reached the specific magnification for the optical zoom! Thus they are NOT the same.

 

[coolguy4747]

It IS in fact, the same. When you tap .5x, 1x, or 3/5x, the image ZOOMS DIGITALLY from the starting magnification to the one you tap on. It just happens pretty quickly when you tap, whereas it can be as fast or slow as you want when you pinch. If you pinch at the same speed as the tap speed, EXACT SAME THING. Sorry I don't have any "technical documentation," I just have my own eyes, hands, and iPhone. Maybe you are not really interested in the answer.

 

[thegr8wendt]

It IS in fact, the same. When you tap .5x, 1x, or 3/5x, the image ZOOMS DIGITALLY from the starting magnification to the one you tap on. It just happens pretty quickly when you tap, whereas it can be as fast or slow as you want when you pinch. If you pinch at the same speed as the tap speed, EXACT SAME THING. Sorry I don't have any "technical documentation," I just have my own eyes, hands, and iPhone. Maybe you are not really interested in the answer.

Assuming the publication I've referenced is correct, and some of the other replies here support that... When I'm at 1x optical magnification on the main camera and I tap the 5x it should change to the telephoto lens and be at 5x optical. There shouldn't be any digital zoom involved (unless the phone decides to select a different lens because of the light situation).

 

[bousozoku]

Thanks for the reply, but actually some of the other responses are not correct. As you stated; Option 1 appears to be using digital zoom, while option 2 tends to lean towards optical zoom. Of course I understand there will be exceptions in different light situations.

Part of the problem is that Apple marketing is misusing "Optical zoom". They have no zoom lenses.

They have 3 cameras and the 48 MP camera is either used fully or used at half the resolution (cropping) to provide 24 MP, to effectively give a closer frame.

 

[coolguy4747]

Assuming the publication I've referenced is correct, and some of the other replies here support that... When I'm at 1x optical magnification on the main camera and I tap the 5x it should change to the telephoto lens and be at 5x optical. There shouldn't be any digital zoom involved (unless the phone decides to select a different lens because of the light situation).

As I said above and is very clear in the article, it is referring to PHOTO mode, not video.

I'll leave you with this, what do you think is happening here?

 

[thegr8wendt]

Part of the problem is that Apple marketing is misusing "Optical zoom". They have no zoom lenses.

They have 3 cameras and the 48 MP camera is either used fully or used at half the resolution (cropping) to provide 24 MP, to effectively give a closer frame.

Your reply suggests that there is only 1 sensor shared by 4 different lenses?

From what I understand there are 4 different lenses, each with a dedicated sensor. Only the main lens has a 48 MP sensor (at 1x). The other fixed lenses (wide angle .5x and telephoto 3x/5x) use separate 12 MP sensors. So it sounds like the only true optical "magnifications" are the .5x, 1x, and 3x or 5x depending on the model.

 

[bousozoku]

Your reply suggests that there is only 1 sensor shared by 4 different lenses?

From what I understand there are 4 different lenses, each with a dedicated sensor. Only the main lens has a 48 MP sensor (at 1x). The other fixed lenses (wide angle .5x and telephoto 3x/5x) use separate 12 MP sensors. So it sounds like the only true optical zooms are the .5x, 1x, and 3x or 5x depending on the model.

Magnification, not zoom. 1x would be like human sight. That would be like a 50mm lens on a 135 Format sensor or film.

Zoom range is not zero. Fixed focal length lenses have no zoom factor because they only have one focal length.

There are 3 lenses on the back and 1 lens on the front, plus whatever Face ID uses, and sensors for each to record video or still photos.

 

[thegr8wendt]

Magnification, not zoom. 1x would be like human sight. That would be like a 50mm lens on a 135 Format sensor or film.

Zoom range is not zero. Fixed focal length lenses have no zoom factor because they only have one focal length.

There are 3 lenses on the back and 1 lens on the front, plus whatever Face ID uses, and sensors for each to record video or still photos.

Thats what I meant... magnification, I'll fix that above so there is no confusion. All lenses are fixed magnification, all lenses have their own sensor, all of the lenses can only "zoom" digitally.