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06-19-2021, 11:19 AM - 2 Likes   #31
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Ultimately it depends on whether you print or not.

When I capture a raw image with my K-1 , when preparing the picture for screen/web viewing I downsize it to 2158x1440 pixels. Reason being that my monitor is 1440 pixels tall, so I can view the image at 100% view without my graphics processor having to downsize it and perhaps introduce softness. That size is a reasonable compromise for most viewers depending on their screen resolution. So my web published images are 3.1 MP

Now if I want to print an image, my printer requires 300ppi so for a 24"x16" print I need a 7200x 4800 pixel image, ie a 34.56 MP image.

It is simple maths folks

06-19-2021, 02:36 PM - 1 Like   #32
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QuoteOriginally posted by pschlute Quote
Ultimately it depends on whether you print or not.

When I capture a raw image with my K-1 , when preparing the picture for screen/web viewing I downsize it to 2158x1440 pixels. Reason being that my monitor is 1440 pixels tall, so I can view the image at 100% view without my graphics processor having to downsize it and perhaps introduce softness. That size is a reasonable compromise for most viewers depending on their screen resolution. So my web published images are 3.1 MP

Now if I want to print an image, my printer requires 300ppi so for a 24"x16" print I need a 7200x 4800 pixel image, ie a 34.56 MP image.

It is simple maths folks
And 36mp isn’t high these days. 50/60/100 the sky seems to be the limit.
06-19-2021, 02:47 PM - 2 Likes   #33
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QuoteOriginally posted by UncleVanya Quote
And 36mp isn’t high these days. 50/60/100 the sky seems to be the limit.
Yes, the sky really is the limit.

With 100 to 400 billion stars in the Milky Way, pictures of the sky do demand lots of pixels!
06-19-2021, 06:56 PM   #34
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Has anyone else seen these Photoshop ads touting some feature to squeeze more pixels into your image? No idea how that works and no interest in finding out, but it seems it's still something people fall for.

06-19-2021, 10:08 PM - 1 Like   #35
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QuoteOriginally posted by pkboy Quote
Has anyone else seen these Photoshop ads touting some feature to squeeze more pixels into your image? No idea how that works and no interest in finding out, but it seems it's still something people fall for.
Upsampling an image by adding more pixels is not new, It has been around for years. What has changed during this time is the the ability to tweak the algorithms to improve the result.

"AI learning", whether you like the phrase or not, is the latest "tweak". It is not just Adobe who are using this technology,

It works extremely well. You are suggesting it does not, without any knowledge of it, and without any intention to find out. That attitude helps no-one.
06-19-2021, 10:53 PM   #36
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QuoteOriginally posted by pschlute Quote
Now if I want to print an image, my printer requires 300ppi so for a 24"x16" print I need a 7200x 4800 pixel image, ie a 34.56 MP image.
300ppi (native) may or may not look sharp. Perceived sharpness depends on how many pixels are there to describe a picture element. This is a trick, consciously or unconsciously used by promoters of cameras. Some promoters of Fuji shows us the amazing medium format details of a skin and eye of a person's face, without mentioning that the person's face cover the image frame from edge to edge. If there are 1000x1000 pixels to define the iris of an eye, the detail is for sure amazing and this has nothing to do with medium format. The same picture could be taken with an apsc camera, also showing amazing details of skin, eye, hair, provided that there are enough pixels to sample the image feature. Yarrow's photograph of an elephant, filling the frame of a D810, even printed a couple meters wide (perhaps ~100ppi native, or less), still shows amazing elephant detail. An elephant is very big, and a detail of elephant skin wrinkle is proportionally big.
06-20-2021, 08:25 AM - 5 Likes   #37
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QuoteOriginally posted by biz-engineer Quote
The ultimate secret that no one ever told is that the megapixels needed is entirely relative to how much detail worth looking by human being, is present in an image, i.e how many pixels (image samples) are used to describe an image detail.

This secret trick has been largely used, and is still being used by David Yarrow, who produced gallery prints the size of pools table, of images captured with a D810 and D850. In all his images, the subject occupy a large part of the image frame, such that even printed 10 feet wide, the subject details still look well defined to the human eye.

Well yes, but the overwhelming majority of non-camera-obsessive photo-looking-at people don't respond primarily on the basis of how much detail they can see. If fine detail in huge prints was their main aesthetic concern then they wouldn't all be using smartphones.

The overwhelming majority of people respond to photos on the level of what it makes them feel. They respond to the subject of the photo, to the composition and the light, and even. . . dare I say it. . . to the meaning.

I've been in galleries with non-photographer friends, and I've observed them looking at huge and technically perfect prints of subjects and light that don't evoke any sense of an emotional response in them. They just shrug and move on along to the next thing on the wall. More often than not, the photograph that makes them stop and look for the longest time is a smaller print full of technical imperfections that grabs their eyes because it makes them feel something that has a meaning for them.

06-21-2021, 11:05 AM - 1 Like   #38
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More pixels mean less likelihood of aliasing, moire.

Watch out when you downsample, as this could give rise to these effects as pixel-count is reduced. At least I think so...
06-21-2021, 01:43 PM   #39
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QuoteOriginally posted by biz-engineer Quote
How many megapixels do you need?
Need or want? Today, I feel like I need 16MP but want 24MP (or more).

Ultimately it depends on what I'm going to do with it. But I also see an analogy with horsepower in engines. The lowly 100 HP in a Mazda 2 (aka Demio) is all you need for good fuel economy and a spirited drive in a lightweight car. Yes, more horses would be a thrill, but not at the gas pump nor for speeding citations.
06-21-2021, 08:27 PM   #40
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Megapixel assumptions…

Most of the replies concerning megapixels tent to concentrate on pure mathematical calculations and while they’re not wrong, those aren’t the only values that need to be taken to account.

Higher resolutions in my experience increase the ability for overall better photo quality. Sharper images while also also affecting tonality. Careful downsizing with good algorithms also can increase that effect, or make it worse. The big problem for me is that a pixel is not necessarily the same as another pixel. There seems to be a big difference is how pixels are rendered from one camera or sensor to another.

Years ago, I was shooting with a Nikon Coolpix 7100. A 10 megapixel camera. (I was largely shooting film at a time so I didn’t want or need a DSLR) However, I still wanted decent quality in a compact camera. The theory on this camera was to use a slightly larger sensor than what most bridge cameras at the time was using (a 1 1/7” vs a 1 1/2.5”) and less megapixels 10 vs 16. The idea is that the photo buckets would be larger and be able to capture better photo quality with increased tonality. My personal observations on this camera seem to support this although the differences are subtle, not night and day. And you really need to process the photo from raw to get the full benefit.

So I find this to also be the case going from APS-C, to full frame, to 44/33 medium format. However, technology also changes the equation too. Pixel density on a sensor is getting to be less of a problem, but it still makes a difference. So you have to factor in generational changes in the sensor as well as the software to make a decision on how that affects resolution.

Also, realistically, to upgrade your resolution to something noticeable, you need to double what you have. That part is just math. How many MP it takes to fill out a rectangle. 16mp to 24mp is nice, but not a particularly big jump. You ideally need to go to 32mp. Realistically, to have a substantial jump you need to multiply that number by 4.

And lastly, screens seem to be more forgiving that printing. Cellphones with their 12MP photos are awesome on screen, but many tend to fall apart when you’re PROCESSING for print. I’m sure there are many nice photos taken in more acceptable conditions, but when you start to print them with an eye for fine art the post processing is possible, but frustratingly slow. Which brings the last point.

Eventually technology (as Apple and others are beginning to show with their infant stages of AI and computational photography) will make it so that none of this will matter much in the very near future. We will be able to process anything to look like anything else soon.

So I’m here going blah blah blah….

The short point that I’m trying to make is that resolution is nice, but you only need as much resolution as you need. But resolution can also make other parts of the rendering worse if the technology hasn’t caught up. And that the argument won’t even matter in a few years.

James
06-21-2021, 09:45 PM   #41
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So how many mp do they use for the roadside bill boards. 🤔
06-21-2021, 09:51 PM - 1 Like   #42
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QuoteOriginally posted by regbaron Quote
So how many mp do they use for the roadside bill boards. ��
What's on the billboard? One pixel is enough to represent a square.

Now for a closeup view of fine detailed artwork, 400 ppi may even be appreciated.

The 300 ppi rule is too general.
06-22-2021, 12:50 AM - 1 Like   #43
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QuoteOriginally posted by regbaron Quote
So how many mp do they use for the roadside bill boards. 🤔

Billboards are usually printed at 30 dots per inch.

No, that's not a typo -- they use thirty dots (pixels) per inch. As with all photographs though, you usually look at a billboard from far enough away that your eyes can't resolve the individual pixels, so it doesn't matter that each pixel is a splodge of ink 1/30th of an inch across.

Of course, pixel peepers will prefer to examine the billboard at 100% to check that the sharpness hasn't been affected by ink bleeding between one dot and another.
06-22-2021, 12:57 AM   #44
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I would say 6 or 10 megapixels is more than enough for my use, as I mostly place my photos into a web gallery. Sometimes I order prints of my images, but only at 10*15 cm size.

I have also made a 20*30 cm print from a frame of Kodak Gold 200 colour negative film. To my eye its quality looked just as good as on a 10*15 cm print.

Last edited by artrasa; 06-22-2021 at 01:00 AM. Reason: Added a remark
06-22-2021, 08:55 AM   #45
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10-12 has historically been good enough for my needs, but I'll take 24 as an added bonus that comes with the other advancements in in sensor technology.
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