8k views

### What is "Hyperfocal Distance"?

I'd like a clear & easy-to-understand (especially for non-physics-types) explanation of what Hyperfocal Distance is, how it affects photographs, and what determines its value.
• 11k
20k views

### What is the EV scale?

I have seen an "EV" (exposure value) scale that's sometimes used to express a camera's exposure settings, or scene brightness. How exactly does this scale work?
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8k views

### What are the theoretical minimum and maximum apertures?

Is there such a thing as a maximum aperture that a lens can be open to? What about a minimum aperture that it can be closed to? Do these concepts even make any sense? Is there a lens with the ...
4k views

### What is the "Circle of Confusion?"

I know that when I want to calculate Depth of Field by hand one of the variable elements in that equation is the Circle of Confusion. In layman's terms, what is the "Circle of Confusion," how do I ...
3k views

### In what way does the lens mount limit the maximum possible aperture of a lens?

In many answers to questions about different aspects of really large aperture lenses it's pointed out that the lens mount sets a hard limit on the maximum possible aperture of the lenses to that ...
• 8,288
11k views

### How do you determine the acceptable Circle of Confusion for a particular photo?

I've noticed that several online and/or downloadable Depth of Field Calculators use different values for the acceptable CoC (Circle of Confusion) for some of the same camera models/sensor sizes. This, ...
• 175k
590 views

### Does an aperture value exist, where a lens creates a brighter image than the real view?

So (without limitations of the viewfinder for example) looking through the viewfinder creates a brighter image than normal view would be. The lens would then work like a funnel(collects light from ...
• 432
1 vote
2k views

### What is the relationship between lens diameter and exposure?

All of the online calculators for exposure, I have seen, factor in time, film speed, and aperture (which is a function of the iris diameter and the focal length of the lens). However I would have ...
• 880
473 views

### What's the intended use of lens with f-numbers close to or "faster" than f/1?

Lens with f/1.2 are rather expensive and not very widespread. Lens with f/0.95, f/0.85, f/0.8 do exist but they are also very expensive and quite rare. Lens with f/0.7 are so rare that some of them ...
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