Q1: Let's talk about the lenses first. Most camera phones have plastic lenses. Are plastic optics systematically not going to give good results or are some of them acceptable?
A: Some of them are acceptable. It depends on their materials; how
Expert Quote
"Some of them (plastic) are acceptable. it depends on their materials and how they are built."
they are built. But, unfortunately, most manufacturers won't say what kind of glass or plastic are used so you will have to make some tests yourself to confirm if it's good or not.
Q2: Do we typically see plastic lenses or glass lenses in regular digital cameras?
A: Most regular camera manufacturers use glass optics, but unfortunately, sometimes there are no specs and there is no mention which material was used on their lenses.
Q3: A few years ago camera phone makers started mentioning that they had special lenses. For example, they'll say their camera phones have "Carl Zeiss lenses." Does it sound good only because it's in German, or does that mean it's actually better?
A: Well, in fact it actually is better because Carl Zeiss is a world
renowned lens manufacturer, and they have a long history of great lenses in their line. So many manufacturers came around with Carl Zeiss lenses; there are many other lens manufacturers that have partnerships with other camera makers and that will give you a good hint on quality lenses. It means that those lenses will be better than non-branded lenses on camera phones.
Q4: In other words it's a valid hint about the potential quality of the optics?
A: I agree.
Q5: Do other German-sounding names also mean quality?
A: We got other German manufacturers that are well-respected. There are tons of other respected lens manufacturers but their use will depend on the camera manufacturer.
Q6: What kind of problems could poor optics cause in the pictures made with camera phones?
A: Optics problems will differ: it can be distortion, blurriness,
What we learned
There's also something called shading - it means the corner of the picture will be darker than the center.
chromatic aberration, and vignetting (darker corners). Most of these problems can be seen in any lens, but a professional lens will control these problems way better.
Q7: What's the worst problem of all those problems you mentioned?
A: I would say the worst is the lack of sharpness.
Q8: So whether it's on focus or not, it might still be a little blurry because of the components?
A: Exactly. Having lots of megapixels is meaningless if the lens is sending a blurry picture to the sensor.
Q9: So a camera phone buyer should look at samples from a specific phone and try and spot those problems. You also mentioned chromatic aberration, what is it?
A: Chromatic aberration is quite a difficult term. I always use Pink Floyd's "Dark Side of The Moon" album to explain that kind of thing. You might remember the album's cover and its picture of a prism with a ray of light going through it and spreading into a rainbow? It means that when white light travels into matter it will bend, and the wavelengths will not all bend at the same angle, spreading the light. That is not something you want on a lens. Lets say your subject is a white dot on a black background. If the lens is producing too much chromatic aberration, instead of having a precise white dot on the center of the imaging device, you will have a mini rainbow. Manufacturers use low-dispersion lenses to avoid that problem, but simple camera phones use very simple and tiny optics, so that is something that might occur in very affordable camera phones.
Q10: What does that mean exactly - the whites will look slightly like a rainbow?
A: No, it means that if you look at very contrasting subjects, for example branches against a bright sky, the edges of the branches could appear as purple fringing. Sometimes, people call it "purple fringing," because that's how we see chromatic aberration in natural pictures most of the time: purple fringing against very contrasting subjects.
Full Menu
