Relationship between pixels and cropping?

[unpopular]

No, you would need a 24MP camera to get the same resolution. To double the resolution (pixels/mm) you need 4 times the total pixels.

Strictly speaking, this only applies if you take the recorded pixels and shift them to overlap. I only know of one processor (RPP) that allows this kind of treatment all others interpolate similarly to super-resolution - also known as "demosaic", which sounds a bit more sexy, I guess.

I do not know how interpolation plays into this, though certainly it would one way or another.

 

[Peeb70 6]

I don't really know. If you are going to crop the image to the same size it should be approximately the same, assuming sensor "everything is equal".

I'm just wondering if in the future, superlong lenses will become irrelevant, since you could just crop a portion of the photo to a large size without the need for the reach of a super

I never can remember...which weighs more, a pound of feathers or a pound of gold??

Ha!

The reason I ask is that I was thinking about the future of photography. As sensors get better and better, will the need for big glass diminish? If you capture an image with a GB of data, you can crop away and draw out the tiniest part of an image captured with, say a 35 or 50mm lens. Most people would stop carrying long tele lenses, I think. Does that make sense?

BTW, I'll happily give you TEN pounds of feathers for one pound of gold.

The future of photography will be whatever direction the market takes it in, period. Every yakadoodle and his brother has some prediction about how this will be the future of all cameras or that will be, etc - but truthfully even as the technology advances I'd be willing to bet that 10 years from now the biggest share of the market will still be cameras that use the same lenses as DSLR's do right now, or at the very least are capable of using those lenses.

Most of us "serious" amateurs have a pretty decent amount of coin wrapped up in those lenses, and honestly I'm not interested in "upgrading" to any camera system that is going to require me to have to go out and replace my glass.

Most pros probably feel the same way for the most part. Smaller and lighter isnot the end all be all holy grail for a lot of us. I like a camera with some heft to it. I don't have delicate little hands, I've got bear paws. My D7100 is about as small as I ever want my camera to be, any smaller and it would be increasingly difficult for me to use.

You make some excellent points, but I see smart phones pushing 'real' cameras out of the way on a regular basis right now. Where a soccer Mom used to snap pics of the big game on a Canon Rebel, she now shoots with an iPhone 6+. I'm not saying that serious photographers are interested in this path, but I don't thing that the push for smaller and lighter will be totally ignored, either.

Just my take.

Yup.. if I had a dime for every "10 years from now all cameras will be smart phones" blog posts and articles I'd be richer than Donald Trump...lol. But the truth is, I don't see it happening.

The DSLR market isn't driven by soocer mom's and cell phone snappers. Sure, it got a boost from those sales back in the age of the flip phone where you couldn't get a recognizable photo from a cell phone but entry level DSLR's got cheap enough for a soccer mom to want one.

They lost some of that market when cell phones improved to the point where you could actually get usable pics from them in some more common shooting situations. But strangely enough the DSLR market is still going strong and companies like Nikon are still making billions of dollars a year despite all the blog posts about how someday the cell phone will be the only camera on the market.

Truth is the market for DSLR's is a different market. Always has been. There was some crossover for a while, sure. But even as the cross over faded DSLR's are still going strong. They are now, and will be 10 years from now.

You can't defy physics. A bigger sensor means more light. Bigger glass, more light. Photography, it's all about light. Smart phone sized lens? Sensor small enough to fit in smart phone? Only so much you can do. Period.

OK, but for me (personally), when DSLR's (or their technological successors) get to the point that they can amass enough data with a 35 or 50mm lens that I can 'blow up' a portion roughly equivalent to what (say) a 300mm lens would grab with excellent quality, I'll have to ask myself if I really want to spend the money for that lens and tote the big boy around.

Just me.

 

[Peeb70 6]

If I shoot a pic with a 6 MP camera at 200mm, can I get the same picture clarity shooting a 12 MP camera at 100mm and cropping?

(Assume lenses are similar lens quality, and that DOF is not an issue).

No, you would need a 24MP camera to get the same resolution. To double the resolution (pixels/mm) you need 4 times the total pixels.

Nice! Did not know that. Thanks.

 

[robbins.photo]

OK, but for me (personally), when DSLR's (or their technological successors) get to the point that they can amass enough data with a 35 or 50mm lens that I can 'blow up' a portion roughly equivalent to what (say) a 300mm lens would grab with excellent quality, I'll have to ask myself if I really want to spend the money for that lens and tote the big boy around.

Just me.

When they get to that point then you'd be looking at shooting the heavier, 300 mm lens so you could get usable shots at 1000 mm and beyond, or a 600 mm lens so you could sit on your back porch and shoot birds in the next county.

Of course you'd better have a 64 Terrabyte SD card to store more than 1 or 2 pictures on, and of course your still not looking at an adequate cell phone replacement because the data your talking about? It's light. Small sensor, small lens, small amount of light, far less data so won't work nearly as well as the larger sensor, bigger glass combo.

Thats the part of the equation that most of these "cell phones will replace DSLR" articles completely miss of course. As the technology improves and cell phone picture quality improves, so does DSLR - so being able to take the equivalent photo to what a DSLR can take now with a 300 mm lens with a cell phone 10/20/30 years from now doesn't mean cell phones replace DSLR's, because a DSLR 10/20/30 years from now will still stomp that futuristic cell phone into the dirt an be able to take pictures that would probably blow our minds today.

More light, more data, better end results given the same level of technology.

 

[wfooshee3 2]

The sensor is 2-dimensional, the lens's focal length is 1-dimensional. The sensor is area, the focal length is...... well, length. If you are trying to get the same "resolution" with half the focal length, you have to square the double of the pixel count (multiply by 4, not by 2,) thus the 24MP referenced in the earlier post.

But you can't compare a 24MP camera to a 6MP camera. the image capture will be so vastly different, what with lower noise, better ISO, whatever else the newer camera with the higher resolution sensor is capable of.

What you might be asking is, "What is a reasonable limit for cropping a picture and still receive useful results?" Can I get by with less lens if I have enough megapixels? The answer to that is, "It depends."

It depends on the final purpose of the image. I shoot with a 16MP camera, and as little as a quarter of the frame still lets me post images 1280 pixels on the long side. I probably wouldn't want to print that to fill a 24-inch frame, though. But I will say that it's a LOT easier to get a good crop from the 16MP camera than it was with the 6MP I had 7 or 8 years ago......

 

[Derrel]

BTW, I'll happily give you TEN pounds of feathers for one pound of gold.

Make it 15 pounds of feathers and I'll consider it a done deal. ;-)

 

[astroNikon]

I don't really know. If you are going to crop the image to the same size it should be approximately the same, assuming sensor "everything is equal".

I'm just wondering if in the future, superlong lenses will become irrelevant, since you could just crop a portion of the photo to a large size without the need for the reach of a super

Well I take photos of things say 11 miles away. Then I crop the snot out of the image. And the image seems better using my FF d600 24mp camera than my Nikon d7000 16mp DX crop camera using a Tamron 150-600 @ 600mm.

The density of the d7000 is greater than the d600, so it should be better. But it's not (unscientifically visually evaluated).

Now I would love to test it against a Nikon p900 bridge camera too.

 

[Derrel]

Well I take photos of things say 11 miles away. Then I crop the snot out of the image. And the image seems better using my FF d600 24mp camera than my Nikon d7000 16mp DX crop camera using a Tamron 150-600 @ 600mm.

The density of the d7000 is greater than the d600, so it should be better. But it's not (unscientifically visually evaluated).

Now I would love to test it against a Nikon p900 bridge camera too.

This phenomenon has been noted before; in tests of specific lenses with both APS-C and FX-sized sensors, the higher-resolving combo always seems to be the FX-sized sensor. Why? I suspect because the physically larger sensor requires far less magnification to arrive at an equal-sized comparison image. The smaller-area APS-C sensor might have greater pixel density, yes...but...making an actual photographic image to evaluate demands that the lens be able to convey information to teeny-tiny pixels...and then, the small-sensor camera's image must be enlarged significantly more "diameters" (the actual technical term) to crete the image which will be looked at an evaluated. So, bottom line...an image that is evaluated is a product of the PAIRING of both the sensor AND the lens...

SImply put...right now, today, 2015...it's easier to start with a much LARGER IMAGE capture area than it is to magnify a smaller image capture area more highly. We saw the same,exact thing for decade before; 4x5 sheet film lenses do not need to be ultra-high resolution lenses...the sheer image AREA, the SIZE of the negative means that a big print can be made with a 4-diameter image enlargement. making the same-sized final print from a half-frame 35mm frame would require 1) incredible lens performance AND 2) incredible film or sensor performance.

JUST this month, The Luminous Landscape shows the power of a compact camera with a 600mm equivalent zoom lens and the newish "1-inch sensor" made by Sony, and used in Canon, Sony, and Panasonic cameras. Using the "1-inch" sensor, d-slr-like detail can be captured. Reichmann says he's going to consider the new Canon when he needs a very long lens option.

 

[thereyougo!1]

Well I take photos of things say 11 miles away. Then I crop the snot out of the image. And the image seems better using my FF d600 24mp camera than my Nikon d7000 16mp DX crop camera using a Tamron 150-600 @ 600mm.

The density of the d7000 is greater than the d600, so it should be better. But it's not (unscientifically visually evaluated).

Now I would love to test it against a Nikon p900 bridge camera too.

This phenomenon has been noted before; in tests of specific lenses with both APS-C and FX-sized sensors, the higher-resolving combo always seems to be the FX-sized sensor. Why? I suspect because the physically larger sensor requires far less magnification to arrive at an equal-sized comparison image. The smaller-area APS-C sensor might have greater pixel density, yes...but...making an actual photographic image to evaluate demands that the lens be able to convey information to teeny-tiny pixels...and then, the small-sensor camera's image must be enlarged significantly more "diameters" (the actual technical term) to crete the image which will be looked at an evaluated. So, bottom line...an image that is evaluated is a product of the PAIRING of both the sensor AND the lens...

SImply put...right now, today, 2015...it's easier to start with a much LARGER IMAGE capture area than it is to magnify a smaller image capture area more highly. We saw the same,exact thing for decade before; 4x5 sheet film lenses do not need to be ultra-high resolution lenses...the sheer image AREA, the SIZE of the negative means that a big print can be made with a 4-diameter image enlargement. making the same-sized final print from a half-frame 35mm frame would require 1) incredible lens performance AND 2) incredible film or sensor performance.

JUST this month, The Luminous Landscape shows the power of a compact camera with a 600mm equivalent zoom lens and the newish "1-inch sensor" made by Sony, and used in Canon, Sony, and Panasonic cameras. Using the "1-inch" sensor, d-slr-like detail can be captured. Reichmann says he's going to consider the new Canon when he needs a very long lens option.

Obviously he's hoping to get back in with Canon. Apparently he bought his own 645Z after loving the camera - he's made a few posts on pentaxforums' medium format section.

 

[WayneF]

If I shoot a pic with a 6 MP camera at 200mm, can I get the same picture clarity shooting a 12 MP camera at 100mm and cropping?

(Assume lenses are similar lens quality, and that DOF is not an issue).

You are confusing sensor size with megapixels.

Shooting 100 mm with a half size sensor (size in mm) is the same view as a 200mm with a full size sensor.

But megapixels is a resolution thing. And megapixels is area, and 2x area is 1.41x dimension, so you're talking 100mm and 141 mm, if the same sensor size. But the view still depends on the sensor size.

 

[WayneF]

The density of the d7000 is greater than the d600, so it should be better. But it's not (unscientifically visually evaluated).

Now I would love to test it against a Nikon p900 bridge camera too.

Both are 24 megapixels, but the FX sensor is 1.5x larger than the DX. That means the DX has to be enlarged 50% more, just to view same size. That enlargement reduces its effective resolution.

The P900 has a crop factor 0f 5.55, 16 megapixels. FX is 555% larger, so P900 has to be enlarged 555% more, just to view the same size.

 

[unpopular]

The density of the d7000 is greater than the d600, so it should be better. But it's not (unscientifically visually evaluated).

Now I would love to test it against a Nikon p900 bridge camera too.

Both are 24 megapixels, but the FX sensor is 1.5x larger than the DX. That means the DX has to be enlarged 50% more, just to view same size. That enlargement reduces its effective resolution.

The P900 has a crop factor 0f 5.55, 16 megapixels. FX is 555% larger, so P900 has to be enlarged 555% more, just to view the same size.

No. If the image were made larger on a full frame camera relative to a smaller format, then crop would not be a factor and would not need to be considered. Image circle has no bearing on magnification. Magnification is the same on my FF 35mm lens as it is on my Fujian 35mm lens which barely covers APS-C.

It's not the projected image that changes on a crop sensor, the backfocus distance on either is the same - otherwise you'd focus past infinity whenever you used a FF lens on a smaller sensor - it's the relative size of that projection to the format. This makes objects on an APS-C sensor "feel" like they're magnified. They aren't. It's only that their image is bigger when compared to the sensor. This thing kinda bumbled me up too for a long time until I started thinking about it.

Here's an experiment.

Try taking a FF lens and a crop lens of identical focal length. Set both lenses to infinity. Tape peice of paper to the wall in a darkened room opposite a bright window. Hold the APS-C lens up toward the window. Find two features, and mark their location.

Do the same with the full frame lens. Line up the same features. You'll find that both lenses represent that distance the same way; the projected feature is the same absolute size on the paper.

However, you'll find that the full frame lens has a larger circle. This is because the full frame lens has a greater field of view than the crop lens, and this additional information is what fills that space. The full frame lens is able to "see" more stuff, but because the projected image is the same size, then the only way it would work geometrically speaking is to make the circle bigger.

Now, imagine a camera with an infinite resolution, an infinitely large sensor and a lens that can cover that sensor.

You'll have a camera that can zoom in infinitely, and likewise, zoom out to a true 180-degree FOV - simply by cropping the image in Photoshop.

 

[AlanKlein80 19]

I put together this graphic to explain crop size.

 

[AlanKlein80 19]

As you can see, the smaller sensor is just seeing a smaller portion of the same image so there is an appearance of 2x magnification. So really, it's just smoke and mirrors.

 

[WayneF]

No. If the image were made larger on a full frame camera relative to a smaller format, then crop would not be a factor and would not need to be considered. Image circle has no bearing on magnification. Magnification is the same on my FF 35mm lens as it is on my Fujian 35mm lens which barely covers APS-C.

I wasn't speaking of the lens or lens magnification at all. I was simply speaking of enlarging the sensor images to viewing size. Assuming we use whatever lenses to get the same view, then enlarging 24x16 mm vs enlarging 36x24mm. The small sensor has to be enlarged 50% more just to be viewed at the same size.

Did you ever do darkroom work? Printing 8x10 from 35mm is a different world than medium film because of this enlargement. The film heights are different, but 36mm to 56mm width is the same 1.5x difference. And it is different.