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Comment by barbariangrunge | Hacker News Reader

I like an old camera I have around here with a 50mm lens because the photos I take with it resemble what I see better than when I use my old smartphone.

Eg, the size of a windmill behind somebody can vary dramatically in size depending on this

If I upgraded my phone, do the new smartphones enable you to take photos like my old 50mm camera, or will I still need my old camera to capture those shots?

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50mm on full frame camera is called a "normal lens" precisely because for most people it mimics their internal perspective / wordlview, so you're not alone:-)

Just look at any given phone specs and see if any of the cameras they offer are near "50mm equivalent" (you may have to dig because primary specs are usually useless - either the completely arbitrary "2x zoom" or the focal length on the specific sensor size such as "4.38mm" Which is true but not useful).

Most phones come with wide and ultra wide lenses. I'm with you and don't like those. Other phones come with zoom lenses of various focal lengths. Most of those on the other hand will overshoot Into 75mm and higher territory.

Worst case, grab a phone with great lens and sensor and zoom it in the store until you get 50mm equivalent... And see if that works.

Note though there may be many other subtle and subconscious things you like about that camera besides focal length of the lens : aperture, bokeh, vignetting, film type, specific aberrations, or even the feel in your hand and mechanics of the shutter and the optical viewfinder. It's certainly more FUN, for me personally, to take a photo with DSLR than an iPhone :-)

You basically have to zoom in on the camera app to get a 50mm equivalent photo. This isn't as bad as it seems though. The 2x quality is quite good on the baseline photos these days.

However, on the "pro" iphone models, they do have a "telephoto" lense that is indeed a 50mm equivalent that will get you the perspective that you're used to.

Here is the one on the iPhone 14 Pro -> 12MP 2x Telephoto (enabled by quad-pixel sensor): 48 mm

Personally, I use an iPhone 8 plus and pretty much always take images on 2x zoom. Because yeah everyone looks better on a longer lense.

Zooming doesn’t correct the perspective though.

I didn’t know they blended lenses to create a 50mm, there must be some post processing tricks to have it look right - are there examples side by side with a true 50mm?

Perspective is determined entirely by the position of the photographer relative to the subject. There will be no difference in perspective if you zoom in with the phone to get the same angle of view you get with a 50mm lens on a full frame camera.

Here is one of many explanations of this you can find online: https://www.photoreview.com.au/tips/shooting/perspective-and....

From the article:

> Changing the lens focal length without changing the camera position has no impact upon the perspective in the scene, even though it radically alters the size of objects within the scene

Radically altering the size of objects within the scene is what most average people mean by perspective. It’s exactly the effect the author of the article is claiming doesn’t happen yet he proved it does immediately.

Is that technically the correct usage of the term perspective? Yes! It’s just not the specific technical usage definition common in optics. But it is correct, as it’s referencing the relative size & position of objects.

The point is that it doesn't do anything that you couldn't achieve by cropping a photo taken with a wider lens from the same position. The relative size and position of the objects doesn't change.

I think there's a lot of misunderstanding here and a lot of optically correct comments are being down voted.

50mm is a focal length. If what you like about 50mm is indeed the perspective (as opposed to other subtle things that may creep like aperture/bokeh or aberration or vignetting of the specific lens) then zooming something to 50mm effective field of view is exactly what will accomplish the goal.

It does. Focal length is just an alternate notation for FOV. 2x crop on a “28mm” photo should geometrically match that of any 1,2/55, except bluriness(bokeh) effect and image quality.

On the iPhone at least, all lenses are wide angle equivalent (24mm, 13mm) except for the telephoto (77mm).

There might be a lens you can attach that narrows it down, but otherwise your old camera will do a better job handling your requirement.

The 2x digital zoom is pretty good on the 14 Pro as it’s still got 12MP to work with. (I’m guessing that combining a stack of slightly misaligned exposures helps it to overcome the loss of color information you’d expect from the quad Bayer layout.)

Digital zoom doesn’t fix the distorted perspective.

The perspective is determined by where you’re standing in relation to the subject.

If you’re talking about wide angle ‘distortion’, then on an iPhone (with the default settings) that’s just what a rectilinear projection looks like with a wide field of view. Zooming in digitally ‘corrects’ that just as much as using a longer focal length would.

You can easily confirm this by taking side by side comparisons. There are many of these you can find by googling, as this is a popular myth. E.g. https://www.photoreview.com.au/tips/shooting/perspective-and....

Your link doesn’t load for me. I’m talking about the contraction of depth when using focal lengths greater than 47mm and lengthening of it when using shorter focal lengths. I guess you can contract depth as well by walking backwards, but at this point your subject is so small you lost a lot of detail. Also, your subject may be gone by then.

Then you mean "depth of field" not "distorted perspective"

The perspective will be the same with a 24mm or 200mm (or any focal length) as long as you stay in the same position relative to the subject, if you crop in the 24mm to get the 200mm field of view you'll get the same image with a much lower resolution and much wider depth of field (ie blurred background)

The perspective distortion happens if you physically move closer to your subject to get the same framing on the 24 as you had on the 200

The thing is though that the depth is contracted disproportionally much more than width and height, which results in a non-linear transformation of perceived dimensions. This causes lines to bend. At 47mm straight lines aren’t bent no matter the distance from whatever there is in the picture. At shorter lengths there are always regions in your photo which are distorted in this way. You can’t fix that by changing your position. The only thing you’ll do is change what object is bent and in so doing maybe make it less obvious.

That's lens distortion, and has nothing to do with depth. Phones will correct it in software automatically, and Lightroom etc can also do it for your DSLR lenses.

It's not usually a concern until you get to <20mm, and especially not if you're going to crop the center of the picture to mimic a 50mm perspective.

I have a 28mm lens with a symmetrical design that shows no distortion

I agree that, in general, wide angle lenses are harder to design in term of distortion control, but it's not a god given rule that all lenses wider than 50mm have to show distortion

Here is a 28mm with virtually no distortion: https://www.lenstip.com/233.6-Lens_review-Leica_Summicron-M_...

Here is the same with a 35mm: https://www.lenstip.com/610.6-Lens_review-Voigtlander_Apo_La...

Here is a 50mm that shows as much distortion as the two I mentioned before: https://www.lenstip.com/205.6-Lens_review-Leica_Summicron-M_...

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