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35

You ask if there is a practical difference. So the answer is yes, albeit a very small one, but some of the other answers have missed it. You're right that the only difference is in the metadata: if you save the same image as 300dpi and 72dpi the pixels are exactly the same, only the EXIF data embedded in the image file is different. (I've even verified this ...


31

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 ...


28

There are some general rules you can use to determine the "maximum" (I use that term loosely) print size. Keep in mind that the quality of a print is often more dependent on what is being printed than its size in megapixels, and even if your image size is not dense enough to mathematically fit onto a certain page size, you can still blow most images up ...


24

Downscaling a larger image on computer is almost certainly going to produce a better result. This is because resizing an image is very processor intensive, and there is a difference in quality between the various resampling algorithms (e.g. Lanczos vs Bicubic). Getting a 5 MP camera to produce a 2 MP image is going to cause the camera to perform the resizing ...


24

I used ImageMagick on Ubuntu to resize those big pictures. convert -resize 10% source.jpg dest.jpg It took awhile, but worked with 1 GByte of RAM, the tool created a 4.7 Gbyte swap-like file for itself. More information is on AskUbuntu.


19

Your only solution is to start an "old digital camera" movement where you espouse the virtues of the very digital look of the earliest digital cameras, and then put on a gallery show in New York with the images blown up to 4 feet by 6 feet to emphasize the very digitarianism they exude. Hey, if they can do gallery shows with iPhone images this should be a ...


18

Please note that the following is a simplification of how things actually work Background: In digital photography, a light pattern is focused by the lens onto the image sensor. The image sensor is made up of millions of tiny light-sensitive sensors whose measurements are combined to form a 2-dimential array of pixels. Each tiny sensor produces a single ...


18

Question about thing like frame rate, resolution or dynamic range of the human eye and how they compare to cameras always have the same problems: The "picture" you see isn't a "single exposure", the eye is constantly moving and adjusting. The part of tee brain that handles vision is really good (and pretty big), it constantly combines the "frames" is gets ...


17

10 years is a very long time in electronics, even the pro level Canon 1D is bettered for resolution by a camera phone these days. There's more to image quality than megapixels of course (I'm sure to get some flak in the comments for the 1D comparison) but I still think you'll be best served by getting a new camera, even if it's bottom of the range, chances ...


17

Short answer: you can obtain some very good results, but only under certain conditions and absolutely not even close to what is shown in the linked video clip. My company, Amped Software, develops image and video processing software for forensic and intelligence applications, so basically we are the real world counterpart of the CSI software. With ...


16

The information above is quite good, so I won't try to compete, but here is a nice infographic: The boxes are the number of megapixels for a print of the size in inches according to the scales on the axes. This is at 300ppi, which is a standard for the print resolution of many images. This great graphic comes from an article at D215.


16

Philip has it spot on there, resampling on a computer will give you more control and access to better resampling algorithms. There's another reason not to select a smaller size on camera and that is if you download your photos and find one that is really good you can keep it in high resolution. If you set your camera to 2 megapixels there's no going back! ...


16

The straightforward answer to your question is very simple arithmetic: 32×300 = 9600 and 18×300 = 5400, so 32 inches by 18 inches at 300 dots per inch is 9600 by 5400. However, it gets a little more complicated when you consider a more complicated relationship between pixels and colored dots in your output medium. For details on this, take a look at ...


15

Bear with me for a second here for some background.... When you downsample a 4000×3000 image to 400×300, you are "discarding" 11.9 million of the 12 million pixels. This clearly reduces "image quality", depending on what exactly you mean by that term. If you go from 1000×750 to 400×300, you're reducing the area by about 6 times. Again, data is discarded, ...


15

Ironically, I just did the math for this in another thread. Image quality is a convolution of all imaging system factors. The resolution of the lens or the resolution of the sensor are not independent factors...they are factors that convolve to produce the final "system resolution". If we use your two cameras as examples, we can calculate the resolutions of ...


14

That means 22.5% more pixels in each direction. 5196 x 3464 instead of 4242 x 2828. (The megapixel value is of course rounded, so the exact resolution varies between cameras.) If the cameras are otherwise comparable, you get more details with highter resolution. However, 12 megapixel is good enough for most uses. If you for example make 4" x 6" prints, you ...


14

No, you cannot say it has infinite resolution, despite what CSI may have people believe :) A film particle puts limits on how fine details can be resolved. It gets complicated though because film has grains of different sizes. Every frame is composed of grains of different sises and they are intermixed. Larger particles are more sensitive to light and used ...


13

jrista has the start of the formula, and it covers images viewed at arm's length quite well. But that 'conventional wisdom' devolves into unreasonable numbers as soon as you get to anything "big", say even a 16x20... requiring 5-6000 px. And if you hit poster size, say 30x40... 9000x12000... 108 MPix?! When you're talking about really big prints, it's ...


13

It certainly is not worth investing in a 35mm film camera for the perceived higher resolution, additional color, or sharpness. To get results you will likely have to either invest in, or at least have access to a drum scanner that gives you the highest resolution possible right now. Otherwise you will likely be scanning on a flatbed that almost certainly ...


13

If you've tried enlarging in Photoshop, the first thing is to experiment with the resampling algorithm (photoshop suggests bicubic smoother as the best for enlarging, but I have found it to be image dependent (if you have an image with a lot of edges vs a portrait or landscape). Rather than smoothing, blurring I would suggest using a denoise program next, ...


12

ImageMagick would be an obvious possibility for the scaling itself. Scheduling a search for new pictures and creating a scaled copy of each isn't built into it though. Most OSes have scheduling capability that could run it though. As a programmer, one thing I'd probably consider would be to use a makefile to handle running the conversion only when a target ...


12

Sensor area doesn't determine resolution in the same way as the film era. Back then simply increasing the area of film would yield a similar increase in the size you could print, and therefore the detail you captured. In the digital world sensors can have different numbers of pixels per cm Both 12MP compact and DSLR will resolve similar levels of detail ...


12

The first two images both have embedded color profiles. The smaller one has Adobe RGB, and the larger one has "TIFF RGB", which happens to consume more space. My guess is you probably want these to be sRGB anyway, with no embedded color profile. In the second case, it's the details. The hand photograph has big areas of the same color, a lot of blur, and ...


12

If the resolution long axis is at least 1920 and the short edge at least 1080 then yes, you can take HD images without having to upscale. However, due to benefits of oversampling, you will make a better HD image by grabbing a 16MP image and then resize with the best available resize method, e.g. lanczos interpolation if available. Another problem you may ...


11

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 ...


11

I have been using various Kodak E100 series slide films (100 ISO) in a Leica, with good optics, and the detailing that my Nikon Coolscan V gets out of these is absolutely absurd. I'd say about 20 megapixels' worth of detail, give or take - easily as good as my 16.7 mp 1Ds II anyway. Given a good exposure and focusing in the first place, of course. How this ...


11

Image size is what if often called resolution, basically the number of pixels stored in the image file. So on a 12 megapixel camera, you can usually choose between 12 MP, 6 MP and 3 MP or similar values. Image quality is independent of size and is usually called compression. This controls how much information is discarded from images while they are saved. ...


10

Actually it is slightly more misleading. 480,000 pixels normally equals 1,440,000 dots but they do get away with only 480,000 actual dots (not pixels) by using something called field-sequential display which is basically 480,000 dots which change colors very fast, sending information for each primary color sequentially. There are only 480,000 dots but since ...


10

It probably doesn't matter very much. The computer has an advantage because it can bring more processor power to bear. You can use more sophisticated algorithms, including tailoring the right one to each image. (And, as Matt Grum points out, you have the larger version available if you change your mind. This is probably the most compelling reason to go this ...



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