Aperture on kit lenses vs smartphone

Started 2 months ago | Discussions thread
bclaff Veteran Member • Posts: 8,580
Re: Aperture on kit lenses vs smartphone

Sam_85 wrote:

I was wondering if anyone can explain why kit lenses typically have aperture ranges of 3.5-5.6 (so not brilliant in low light) whereas my phone (samsung s9) has an aperture of 1.5 giving me much brighter, clearer and less blurry photos in low light (indoors)?...

There certainly are fast lenses for Interchangeable Lens Cameras (ILCs) but they are more difficult and expensive to construct.
For example, here's a 50mm f/1.4 lens :

The black tick marks are the physical aperture (iris) and the blue line labeled P is the entrance pupil.
Notice the blue line diameter matches the diameter of the blue bundle of rays entering the lens.
And also notice the green off-axis bundle is constrained by the diameter of both the front and rear elements.

Because of the lens mount and because of the thickness of the lens there's a limit to how fast you can make it. And as focal length increases it becomes even harder since the lens gets longer and the entrance pupil gets bigger.

Mobile phone lenses don't have a mount to contend with and are much closer to the image plane (the black line labeled I).
And mobile phone lenses are not so thick and the focal lengths are quite low.

So it's easier to make a mobile phone lens with a relatively low f-number like the f/1.5 lens in that Samsung S9.

-- hide signature --

Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )

Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow