More megapixels vs sensor size

SnappingShark

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OK, so let's say I have a 300mm lens on a Micro43rds body (so 600mm FF equiv) - and the camera shoots at 20megapixels.

Now let's say I have a 500mm lens on a FF body and the camera shoots at 45megapixels.

Would the FF get a better crop into the image vs the M43 in terms of quality?

Seriously debating switching to FF from my M43 - as in my head, the image would be better cropped in FF to get that extra 100mm than the actual longer focal length on M43. So seeing if this is also an advantage vs just more light capturing and less noise ability
 
Let's see if I can explain this properly.

On a M43 20MP body, your image will be roughly 5160x3872 pixels.
On a FF 45MP body, your image will be roughly 7744x5808 pixels.

So if you're shooting a 600mm shot on the M43 and want to see what the pixel count would be shooting the exact same shot on at 500mm on a FF camera, you can do some math to find out.

If you half the pixel dimensions by 'digitally cropping in' an image you are effectively doubling the focal length of the lens. Since we don't want to double the focal length and only want to add 100mm to it, just figure out the difference.

500mm = 7744 x 5808 or 45MP (starting point)
600mm = 6453 x 4840 or 31MP
700mm = 5531 x 4148 or 23MP
800mm = 4840 x 3630 or 17MP
900mm = 4302 x 3226 or 14MP
1000mm = 3877 x 2904 or 11MP (half the 'dimensions')

So it looks to me like on a FF 45MP sensor at 500mm, after cropping into a 600mm equivalent shot would still be 31MP after cropping.

Cropping all the way down to match your 20MP's you have now, would yield around a 750mm equivalent shot on your M43. Sounds like a good upgrade to me.
 
Uh boy.


Not to be harsh here, but the argument over this is a bit off.

You still have a reproduction ratio to consider.
The more AREA, (not pixle count) is what will finally determine the end quality.
 
Uh boy.


Not to be harsh here, but the argument over this is a bit off.

You still have a reproduction ratio to consider.
The more AREA, (not pixle count) is what will finally determine the end quality.
Please help me understand what you mean.. To me, if you have a higher quality lens then the more sensor elements you put on the subject the more detail you can capture. Sensor size does not matter. Where sensor size usually matters is in low light performance, but if you are at lower ISOs, it's not an issue.
 
Please help me understand what you mean.. To me, if you have a higher quality lens then the more sensor elements you put on the subject the more detail you can capture. Sensor size does not matter. Where sensor size usually matters is in low light performance, but if you are at lower ISOs, it's not an issue.
Format size = higher reproduction ratio clairity. Ergo, less actual distortion when the image is enlarged.

But my thinking is also involving med. Format.

Ironically, I am going to post three pictures shortly where the camera is a Canon RP, and the lens is a 40+ year old Chinon 55-300.
 
Format size = higher reproduction ratio clairity. Ergo, less actual distortion when the image is enlarged.

But my thinking is also involving med. Format.

Ironically, I am going to post three pictures shortly where the camera is a Canon RP, and the lens is a 40+ year old Chinon 55-3
I just saw a YouTube video by a professional photographer whose cell phone picture was used to create a billboard. He proved that viewing distance is extremely important in determining how many pixels / inch are needed to create a higher quality print, not the sensor size. It is generally accepted that the highest quality prints viewed at arms length will use about 300 pixels / inch, good quality about 200 pixels / inch and you can get acceptable results at around 100 pixels / inch. Older computer displays are a little over 70 pixels / inch and newer displays are at about 100 pixels / inch and even higher. So, it’s not the sensor size, but how many pixels you get on the subject given a good quality lens then how many pixels / inch you use on your print given an agreed upon viewing distance. So, a 24mp sensor is a 24mp sensor whether it’s 4/3rds, asp-c, full frame, or medium format. Yes, I agree that a 60mp sensor image can be printed and enlarged more than a 12mp cell phone image can be printed and enlarged, but for the same viewing distance.
 
I cannot comment on artificial images on a computer monitor, but for sure real images on a light box under a quality loupe, bigger is always better - given the same grain size.
 
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One of the problems with this kind of question is that it assumes that everything else is equal, like the 300mm lens and 500mm lens both have equal performance at all apertures (not very likely in real life), and for that matter, equal equivalent apertures (remember the crop factor scales aperture too). And that the combination of the image sensor and camera software results in identical noise figures (also, not likely), and that the resolution of the 300mm lens is not the limiting factor to final sharpness when the image is cropped, and that the 500mm lens has the ability to resolve an image as well as the 30mm lens. Life isn't that perfect.

The real practical questions are like, is the maximum equivalent aperture with the 300mm on the cropped sensor the same as the 500mm on the full frame? What's the difference in cost and weight? Big glass is expensive, if it's going to be good too. And of course, if you're going to compare sensors, shouldn't they produce images with the same pixel count? Or you've thrown another variable into the mix.

And speaking of pixel count, as has been mentioned, you can't really have that discussion without including at least some reference to the image viewing angle (a combination of image size and distance from viewer). Because once you have pixels smaller than can be seen with the unaided eye with 20/20 vision, you're kind of done.

While we're on that, also don't dismiss a lower pixel count sensor out of hand just because it has fewer pixels. The two factors that don't get menioned nearly enough are, fewer pixels often mean larger pixels, which pick up more light and result in less noise. And some of the new image scaling tools are, frankly scary good. I'm playing with the Topaz apps, for example. Scaling is something they do really well.

While I personally would love to have a set of f2.8 or larger lenses on a full frame camera, I can't justify the expense and my shoulders won't carry the weight anymore. Not that FF cameras cost more, probably not, but the lenses very well might.

I'll add this video, which doesn't answer the question, but does highlight many of the trade-offs.
 
I could point folks to images on Flickr or imagur or the like where an old school P20 phase One MF digital back that is at a paltry 6Mp and has 9µ Fat pixles, still gives off an image that looks like it came out of a 24 Mp Sony a7III.

There is way more to the argument as point out above than simply that.

Crop sensor is still a sensor and if you use a 300mm lens, your still getting a 300mm lens. The 500mm equiv. argument is based on the EQUIVILANT image framing from a 500mm lens.
But its NOT 500mm.

Add in the 4K argument, and sorry folks, focal distance is still focal distance.

With that said, one point to consider is the sweet spot of the lens, its manufacture and moreover overall performance.

With my RP I put on multiple diff. brands of lenses and am getting some serious photography out of it.
so there argument for modern technology is def. in the mix here.
 
Sensor size. And remember, your only gonna be as good as your glass. Really. Also, telephoto lenses are full of glass. Your images pass through a lot of it before making it to the sensor. If you can find a prime lens at the focal length your wanting to shoot. Grab it. Remember this too, I have all the photography equipment that I need. Said no photographer ever. Happy shooting.
 
Hmmm, sort of a apples and oranges thing. FF 44mp vs 4/3 20mp. You are working with different size pixels with the FF have the larger pixels. Now, a Nikon Z7 or D850 are 46 mp FF cameras and the Nikon D500, D7500, and Z50 are 21 MP crop frame cameras with roughly the same size pixels as their FF bothers. The FF sensor is bigger so they can cram more pixels onto it. When I shot my D850 and cropped the image down to roughly 21mp it looked pretty much the same as what I get from my Z50. I like to shoot bugs and other closeup stuff with a macro lens so with the D850 I was cropping away a lot of my pixels where as with the Z50 lets me get close enough without having to crop so much. For me, crop frame makes sense as it does for a lot of wildlife shooters as well.
 
Simply put,

The larger the sensor, the less you must enlarge it to any viewing size.
A 2x crop sensor image must be enlarged twice as much as a full frame sensor image just to view it.
Enlarging 2x more reduces the visual resolution to half.
But in the general case, either likely are still acceptable, except the extreme cases.

The effective focal length being 2x is simply a result of the greater viewing enlargement required. Using any image, simply zooming in 2x more in the photo editor produces exactly the same cropped enlargement effect. It might be more detail seen, but that is NOT more detail created, the 2x enlargement has the loss of resolution (pixels are spaced 2x further apart,, half the dpi). A sample of this editor zooming is shown at Crop Factor and Equivalent Lens Focal Length Explained

The more megapixels, the more detail can be resolved in the lens image.
The more of that is more that survives the viewing enlargement.

The longer the actual real focal length, the more it is enlarged by analog enlargement instead of digital resampling.

The maximum resolution is more sensor size, and more pixels, and a longer lens.

I can offer of what I think is an example at Have our cameras hit a megapixel resolution limit?
with full frame, 36 megapixels, and a mild telephoto lens.
 
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Simply put,

The larger the sensor, the less you must enlarge it to any viewing size.
A 2x crop sensor image must be enlarged twice as much as a full frame sensor image just to view it.
Enlarging 2x more reduces the visual resolution to half.
But in the general case, either likely are still acceptable, except the extreme cases.

The effective focal length being 2x is simply a result of the greater viewing enlargement required. Using any image, simply zooming in 2x more in the photo editor produces exactly the same cropped enlargement effect. It might be more detail seen, but that is NOT more detail created, the 2x enlargement has the loss of resolution (pixels are spaced 2x further apart,, half the dpi). A sample of this editor zooming is shown at Crop Factor and Equivalent Lens Focal Length Explained

The more megapixels, the more detail can be resolved in the lens image.
The more of that is more that survives the viewing enlargement.

The longer the actual real focal length, the more it is enlarged by analog enlargement instead of digital resampling.

The maximum resolution is more sensor size, and more pixels, and a longer lens.

I can offer of what I think is an example at Have our cameras hit a megapixel resolution limit?
with full frame, 36 megapixels, and a mild telephoto lens.
Help me understand your post. My photo monitor size is 2560 x 1440 and a 4k monitor is 3840 x 2160 pixels. My D7200 is 6000 x 4000 pixels, 24mp and my D850 and Z9 are 8256 x 5504, 45.7mp. So, SOOC I'm shrinking everything. Most of the time when I crop, I'm still shrinking as most images in social media don't display full screen. Say I print at 22" x 17" at a resolution of 200ppi, I'm using 4400 x 3400 pixels, so still shrinking. Only under extreme cropping am I enlarging and will usually use Gigapixel AI or LrC enhance, but the AI does a pretty good job minimizing artifacts.

I agree that the more sensor elements you get on your subject the greater the detail that can be captured, IF you have a lens good enough to capture that detail and the scene contains a high level of detail. According to DxOMark.com, my D850 with the best 85mm f/1.4 prime that Nikon makes, which are renown for sharpness, only captures about 35mp of the 45.7mp available.
 
According to DxOMark.com, my D850 with the best 85mm f/1.4 prime that Nikon makes, which are renown for sharpness, only captures about 35mp of the 45.7mp available.

I don't understand that sentence. The D850 is the 8256 x 5504 pixels.

8256 pixels / 35.9 mm width is 230 pixels per mm, which is a resolution of half that, or 115 line pairs per mm (that the sensor can resolve, if the lens did). Maybe what they are said is that the lens cannot? (but I doubt that). That is a pretty high number. But two pixels per line pair is the extreme minimum to detect two lines, and more pixels are viewed much better. Those line pair would resolve much better if several more pixels across a pair (which is pretty much the point of that last page I linked). And 8256x5505 would print 27.5 x 18.356 at a higher 300 dpi (if the printer could do 300 dpi that size).

The D7200 is 6000 pixels / 23.5 mm = 255 pixels per mm, actually greater resolution, but only 2/3 the size which has to be enlarged 1.5x more, reducing 255 to 170 pixels per mm if viewed the same size.

Was there a question? I didn't find one. I think that you are just saying your average photo viewing situation does not need that many megapixels. It is a lot of pixels. Seemingly loaded for bear, but not hunting bear. :)

But larger prints or extreme crops could use it all. I didn't know if you are resampling smaller in the camera or later externally, but I am suggesting that come the day that you shoot that really prize photo, you may wish it were still full resolution.
 

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