Talk:Digital zoom

Benefits of digital zoom

I'm not sure enough of these things to add it to the article, but isn't it the case that digital zoom isn't all bad?

• Digital zooming should do the resizing/interpolating before any jpeg compression. With a low quality setting, this could make a big difference.
• Aren't all images already interpolated to an extent (except in some cases, like images made with cameras with the Foveon X3 sensor)? If that is so, it should theoretically be the case that the digital zoom could do a better job at resizing/interpolating than an external tool, as it has additional information about the specific sensor grid. Is this actually being used by cameras, or do they indeed really only resize using the usual interpolation methods on an image after it has been made without digital zoom?

How do I compare zoom

What is the comparisn between zoom mentioned as 2x 3x or 12x, and zoom mentioned as 35- 105 mm zoom? can anyone please explain.

Read zoom lens. --Stybn 15:54, 1 February 2007 (UTC)

35–135 mm is the ratio 135/35, or almost 4X zoom range. The two specs tell you different things; you can convert one way, from a 2-valued specification to a single ratio, but not back. Dicklyon 16:02, 1 February 2007 (UTC)

That's correct. --Stybn 06:58, 5 February 2007 (UTC)

Self evident?

Some time back, I added a fact tag (citation needed) to this statement: "For cameras that save images in a raw format, however, resizing in post-production will yield results equal or superior to digital zoom." If there's a reliable source for this, fine, but to me it is not self-evident. Some Nikon DSLR, for example, takes advantage of the fact that most of the pixels aren't needed, and is therefore able to read the ones it needs more quickly, and potentially get better raw data than when reading all of them. So let's not jump to conclusions, but stick to what reliable sources assert. I'm going to take it out if nobody comes up with a source soon. Dicklyon 01:51, 5 May 2007 (UTC)

Dick, thank you for bringing this over to the talk page for discussion. I'm not aware of the situation you describe with the DSLR cameras; and I'd like to ask you to explain it more to help me understand. Are you saying that the camera is able to direct more of its processing power at the area which has been digitally zoomed in on, allowing it to potentially capture a better sample of that area due to the freed up processing power? I'm guessing that's not what you're saying, because the processing power would be used to perform the crop at frequent intervals. I'll stop speculating here and let you run with it. I'm looking forward to it, it's always great to learn something new! Cheers, Severisth (talk) 15:07, 28 December 2007 (UTC)

Digital Zoom on under-used sensor

If a camera is capable of 10MP but is normally set to 5MP will the digital zoom make use of the available sensor pixels without too much interpolating until the zoom level means the image is taken from the centre 5MP of the sensor. What level of zoom does this represent? It depends on whether the zoom is measured by the change in image height and width or the area. Pmarfell 22:17, 14 August 2007 (UTC)

Zoom is measured as a linear (height or width) magnification. Using the center 5 MP of a 10 MP sensor would be 1.414X zoom. Dicklyon 22:21, 14 August 2007 (UTC)

I have since read elsewhere that some cameras (some of the Sony range) use smart zoom. This uses the available sensor resolution to avoid interpolation. In that way a 10MP camera that is set to 5MP can get an extra 1.414X zoom before using fewer sensor pixels than required in the image. Pmarfell 21:22, 24 August 2007 (UTC)

"Resizing (interpolation)"

Is it not true that resizing and interpolation are two different things? This is confusing. It is my understanding that resizing a picture does not affect its pixel value, it just streches it. However, interpolation is specifically the act of filling in the missing pixels to make up the original pixel value. IainUK (talk) 22:54, 30 August 2008 (UTC)

"Resizing" doesn't mean a damned thing without further qualification, so I'm dropping it from the article. --Stybn (talk) 00:48, 31 August 2008 (UTC)

I think it would be useful on this page if there was an explanation of the difference between digital zoom which simply crops and streches a picture, and digital zoom which interpolates a picture and retains its original pixel value. I'd write this myself but I am no expert (hence me arriving at this page in the first place). Perhaps someone better qualified might oblige. From a novice viewpoint - this would be helpful. IainUK (talk) 01:22, 31 August 2008 (UTC)

"Stretch" (like "resize") is another common term with no single definition, and thus no meaning outside perception. But if you've interpolated data, you haven't preserved the original data, unless you made a copy first. Maybe some cameras or software do that; I don't know. --Stybn (talk) 17:05, 31 August 2008 (UTC)

Error in the Sample Image

The sample image used to illustrate the effect of Digital Zoom is incorrect and misleading.

It has a width of 752 pixels. The top portion of this image is labeled "50mm". A 50mm lens has a horizontal angle of view of 39.6°. That portion of the image inside the red rectangle is 91 pixels wide, and thus constitutes only about 1/8 the angle of view of the image, or about 4.8°. That's closer to the angle of view of a 400mm lens, not the 200mm lens as is labeled on the image. TCav (talk) 15:30, 12 August 2012 (UTC)

References

That in/out zoomy bush thing's making me feel sick

Just sayin' Mannafredo (talk) 13:10, 11 October 2013 (UTC)