Focal length and aperture relationship quizzes

Lens quiz answers - A mixed bag of lens knowledge

Focal length is tricky to see on a modern lens. If you have a simple one-element lens (picture a magnifying glass), the focal length is the. Aperture (the f/stop), Focal length of the lens, Distance to the subject Relationship between length of exposure/shutter speed and intensity of light/ aperture. Study Flashcards On Photography I: Basics Quiz at Quickly memorize Reciprocal relationship. Controlled by aperture, distance, and focal length.

The design dictates the number of lenses and lens groups required. Click image to view large Generalised photographic lens layout showing showing the principle features. Lens quiz question 7. Most often a chromatic aberration is a slight rimming of colour s around brightly coloured objects. Sometimes it is barely visible.

Lens quiz question 8. What is projected onto the sensor plane from the lens? The sensor plane is a flat plane which is the surface of the sensor. The image from the photographic lens is projected there. The light energy hitting the sensor is converted to electrical signals and stored as an image file. Lens quiz question 9. What is the diaphragm in a photographic lens?

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It has a hole in the centre. This allows light to pass through to the camera from the lens.

Bokeh, Depth of Field and Focal Length explained

This wall is called the diaphragm. It also supports the iris that creates the variable sized gap called the aperture.

Lens quiz question Can the focal length be greater than the measured length of the lens body? Yes… Very long focal lengths make very long lenses.

Some would be unwieldy to use. Many consumer DSLRs have mm focal length lenses but the whole lens often measures less than mm. Telephoto elements do lower optical quality. Modern engineering makes the images acceptable. What would you normally use a macro lens to do?

To take photographs of very small things. The macro lens projects an image onto the sensor at a ratio close to 1 to 1. This is normally printed at a much larger size therefore giving the impression that there has been a magnification of the object. In fact macro lenses rarely actually magnify.

Lens quiz what do you know? - Photokonnexion

The correct name for a lens that enlarges beyond 1 to 1 is a photomicrographic lens. Is the shutter in the lens or the camera? It depends on the camera. DSLR s normally have the shutter right next to the sensor, in the camera body. The cost of putting shutters in all interchangeable lenses would increase the price, weight and size of lenses. However, shutters are slow physical mechanisms.

So in fixed-lens cameras bridge cameras and point-and-shoot cameras the shutter is in the lens.

Npa Photography Quiz

It is smaller and therefore faster, and is cheap since you only buy it once. Shutters would be very slow for such large sizes. A slow shutter makes many types of exposures impossible — e. So the shutter is in the lens where the light beam is thinnest. Which is the fastest lens an f1. A fast lens is one that lets lots of light in allowing short shutter opening. The fastest lenses have the widest apertures. What controls the depth of field?

A lens can only resolve light to a sharp image at one point. Sharpness drops off either side of that point. The depth of field is the zone of acceptable sharpness to the eye either side of the sharpness point. The starting place is that if a lens is focused on 10 feet, then objects at 5 feet and objects at 20 feet will be blurry. Well, the formula people have quantified "blurry", with a term called Circle of Confusion.

That's basically how much blur is acceptable at the CCD plane. And it depends on the sensor size. So depth of field is the range of distances in front of and behind the point of best focus that are still "acceptably sharp," as defined by this COC measure. It depends on focal length shorter gives moreon aperture smaller gives moreand on distance to subject further gives more. And since COC depends on sensor size, it depends on that too.

But to give you an intuitive understanding, try the following. For a particular sensor, depth of field is almost directly related to the apparent aperture size, as seen by the subject.

I'm a budding amateur, and I've read a few basic books. Still, theres a couple of points regarding lenses I haven't quite come to grips with, hence this post.

I'm rather surprised that I still find myself wondering about these things, I guess I've read the wrong books. Anyway, first of all I'd like to apologize up front for posting it here, it didn't seem to fit anywhere. Next I'd also like to apologize for crossposting to several forums. Thanks for your patience.

So over to my questions 1 Focal length. Which length is this exactly? I understand what it means, but I'm just curious as to what exactly is measured here. What exactly determines the max apertuere of a lens?