Alley in Pisa, Italy

by Lars Kotthoff

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Tag Info

Hot answers tagged

30

I think Film vs Digital article by Roger N. Clark answers exactly this question. Let me quote the chart from its summary: The main point is that digital sensors have fixed resolutions and variable sensitivity, while films have fixed sensitivity and varied resolution. Overall, at high ISO (> 400) most of the modern sensors provide higher resolution, and to ...


9

No. Because different films with the same ISO can have different quality aspects, and digital cameras with the same megapixel count can have different quality aspects. There are also many potential variables in processing/development and printing for both film and digital that will effect image quality. You can discuss very specific examples. For ...


9

In general it is not possible to increase the size/resolution/pixel density of an image after it has been captured. If the detail was never present it can't be replaced. There are ways to increase the number of pixels whilst minimizing artifacts (an example being fractal based image resizing). These methods are useful when you need to print large without ...


8

Part of what we're seeing here is (I'm reasonably certain) nothing more than a simple typo (or something on that order) on the part of DPReview.com. According to Canon, [PDF, page 225] the number of wells on the sensor is "Approx. 18.00 megapixels". Those are then reduced to the approximately 17.9 megapixels when the Bayer pattern inputs are turned into ...


8

Pixel density is simply a measure of how many pixels will fit into a given area. It is determined by the size of the pixels: the smaller the pixels, the higher the pixel density. Imagine making two mosaics of tiles on your wall: one uses small tiles, the other uses large tiles. They might end up looking something like this: We can easily see the ...


8

The LCD screen on your camera is a 16:9 aspect ratio, so when you shoot in a 4:3 aspect ratio, it puts black bars in the 'extra' space. Aspect ratio is just the ratio of the height and the width of your image. Your LCD is a 'widescreen' LCD with a fairly common ratio of 16:9, however, most digital pictures are shot at 4:3. When you change your camera to ...


8

Why work so hard? I think you are making this much harder than it has to be. Getting something to be exactly 640 pixels in the image will be difficult, require careful measurements and accurate calculations and is very error prone (and for something really close the internal construction of the lens makes a huge difference and this will be impossible to ...


7

Your intuition is correct. What happened is that technology has improved. There has been lots of small improvements piling up, things like better micro-lenses, gapless microlenses, cleaner read paths, on-chip noise-reduction, less noise gain circuits. All this and more adds up to substantial improvement. Increasing megapixels which reduce pixel-sizes takes ...


7

This is completely normal. Unlike many makers, though, Olympus includes the hot-pixel mapping function on all their cameras, so you can just use that. Remember, a full resolution JPEG from this camera has 15,925,248 pixels. If, say, a dozen of them are defective, that will have a 0.000075% impact on your final results. It's really a non-issue, and not ...


6

There are two reasons why the effective pixels are less than the actual number of sensor pixels (sensing elements, or sensels.) First, Bayer sensors are composed of "pixels" that sense a single color of light. Usually, there are red, green, and blue sensels, organized in row pairs in the form of: RGRGRGRG GBGBGBGB A single "pixel" as most of us are ...


6

I remember seeing a figure of 22MP was "as good" as 35mm resolution (of course, with film it isn't just the ISO, but the manufacturer and age of the film, skill of developer etc.) Higher ISO film tended to have more grain; and higher ISO digital shots exhibit more noise - a similar cause, but the visual appearance is different. Digital ISO noise is related ...


5

It's not easy to compare ISO grade with sensor resolution because they're not related. What's more related is noise ratio versus film grain, but it's not that simple. Film grain behaves differently that sensor noise. Where sensor noise makes you lose detail is where the noise limits the ability to perceive detail. Film has grains of different sizes and ...


5

No, not really. If we could, camera would not be increasing in megapixels all the time. You need more data captured to show or print something bigger. Scaling algorithms have sophisticated ways of inventing pixels, called interpolation, but without more data, those added pixels cannot increase image details. Clever algorithms may look slightly better than ...


5

Resolution first, given that size does not vary much lately (2.7-3"). That lets you check sharpness and focus better, particularly if you use Live-View. Rotating or tilting (vary-angle) can be useful for somethings but is also a liability since it can break. No Pro cameras have such displays because they need to be tough first. You forgot the viewing ...


5

Is resizing a means to increasing the resolution of the image ? Resizing can increase pixel count if you want, but in general it cannot increase the amount of detail. Though in some situations upscaling is necessary (for example, if you want to combine two images). Use Sinc (Lanczos3) interpolation when upscaling the image in Gimp. Even more, resizing ...


4

Yes, it's possible to upsize an image. The most common application used for such work is Genuine Fractals (which I see has now been renamed to Perfect Resize). It can be used as a standalone application or as a Photoshop plugin. The software will enlarge and then interpolate to fill in the "missing" pixels. The company has some complex fractal algorithms ...


4

Pixel density in 2D sensors (*), like any other density, is the number of pixels per unit area. A sensor size is given (usually in mm or inch) and thus its area. A given sensor is divided to separate light sensitive locations, which are the sensor elements, or photosites/sensels. In the most common arrangement, these sensels are square in shape and form a ...


4

I don't know why the term "effective" is used by DPReview, but there are a couple of reasons for the discrepancy between the number of photosites (pixels) on the chip and the size in pixels of the resulting images. Some camera sensors have a strip of masked pixels down each side. These pixels are identical to the bulk of the pixels on the sensor except they ...


4

Most depth of field (DoF) calculations are based on the assumption that the image will be viewed as an 8X10 print at a viewing distance of about 10 inches (25cm) by a person with 20/20 vision. For a 35mm film sized image, that means about an 8X magnification factor. For a blur circle to be perceived as a point at that display size and viewing distance, it ...


3

I found a solution that worked on my 550D (Rebel X2i), the page is about the 5D Mk2 so I guess it works on all canons. http://www.slashgear.com/how-to-remove-stuck-pixel-on-your-digital-slr-2227392/ The relevant part: Test for dead pixels : Left lens-cap on, set camera to exposure 30 seconds black-out image at varies ISO settings. Fix for ...


2

I kind of dispute all the answers and comments about this subject, not just here, but on most forum discussions that cover this topic. I've done some fairly extensive work lately on digital upscaling, and when approached correctly, you can achieve some considerable upscaling without too much blurring, sometimes by as much as 20x or more. In my work on ...


2

A background image on a website doesn't really need to be larger than 1024 x 768. You're designing for the lowest common denominator. And don't forget that the web browser has to suck down every byte you put up there. For a reference, I searched for "web design recommendations screen size" (without the double quotes). So... if the image you took is ...


2

A quick look around on The Googles seems to confirm that Apple Aperture doesn't have an automated way to deal with hot pixels. In any case, I think the best way is to have the hot pixels mapped out in-camera at the RAW level. Some cameras can do this as a menu option, but unfortunately some manufacturers save this as a price-differentiation feature and ...


2

There are more problems with comparing the resolution of film to that of a digital sensor. One problem is that the grain that you see is in fact not the image forming element but a form of noise. The actual elements are much smaller. Also, it matters if you look at B/W film or color film; the image in B/W film is composed of silver particles, while most ...


2

While size and resolution are important, the most important factor is probably maximum brightness. I've used several DSLR's that had beautiful screens, but could barely be seen in daylight. A big 3", million-dot screen won't do you much good if you can't really see it. Screens based on OLED will usually provide the best of resolution, contrast, and ...


2

Size and resolution of course. But vari-angle was a pleasant surprise for me. I didn't really care about the feature when buying my Canon 60D. I had a Pentax with a fixed LCD before I didn't really know why on earth would i need one. However. Can't comment on the Nikon, but... I use it on my Canon often now especially when shooting from obscure angles ...


2

It's not quite clear from your question what you mean by "resolution", as the term is often used to describe two not quite related things. Image size in pixels - i.e. 3000x2000 pixels. This parameter describes how much information an image can contain - i.e. the above image has 6 million physical pixels and there is no way to recover any details which were ...



Only top voted, non community-wiki answers of a minimum length are eligible