(Megapixels) War...what is it good for....

[Kayaker72]

Every once in awhile I like to remind myself of a few things. Right now I am thinking about the benefit of MP and how many MP I need, with a nearly confirmed rumor of a R5 with 40-45 MP, a R6 with 20 MP, the 1DX III with 20.2 MP and the rumored "high MP" camera that is potentially 82 MP. Of course, that is just Canon. Sony and Nikon are sporting 40-65 MP in their current cameras. Fuji just released a 100 MP "medium" format camera.

But there are a lot of people talking about all the MPs and needed more MP. Yet, I recall doing the math when I bought my first DSLR, the Canon 7D, and concluding it was time to invest in a DSLR as that was enough resolution at 18 MP.

Being an engineer, I like numbers....so here is a table I put together this morning....

Camera	Megapixels	Horizontal Pixels	Vertical Pixels	Horizontal PPI at 24 inches	Vertical PPI at 24 inches	Horizontal inches at 150 ppi	Vertical inches at 150 ppi	Horizontal inches at 300 ppi	Vertical inches at 300 ppi
5DIII	22.3	5760	3840	240	160	38.4	25.6	19.2	12.8
5DIV	30.4	6720	4480	280	187	44.8	29.9	22.4	14.9
1DX III	20.2	5472	3648	228	152	36.5	24.3	18.2	12.2
Rumored R5	45	8208	5472	342	228	54.7	36.5	27.4	18.2
Rumored High MP	82.7	11136	7424	464	309	74.2	49.5	37.1	24.7
7D	18	5184	3456	216	144	34.6	23.0	17.3	11.5
M3	24.2	6000	4000	250	167	40.0	26.7	20.0	13.3
M6 II	32.5	6960	4640	290	193	46.4	30.9	23.2	15.5
G7X II	20	5472	3648	228	152	36.5	24.3	18.2	12.2

I picked a few of the metrics as:

• The largest print in my house is 24 in x 16 in. I have images up of that size shot with the 7D, 5DIII, and 5DIV. As far as I am concerned, they all look good. Maybe the images shot with the 5DIII/IV are a bit better, but I was also shooting with better lenses by that time.
• I've always heard/read that at normal viewing distances, the human eye can start to discern ~75-150 dots per inch resolution. So, I went with 150 ppi (and yes, I am assuming DPI = to pixels per inch (ppi)).
• Then, at least at one point, it was common for magazines to require images at 300 ppi. Maybe because of this, I've always heard 300 dpi/ppi regarded as the higher end standard.

​
So, given all that, you can see how the cameras stack up. My old 7D was greater than 150 dpi for the 24x16 prints I have up. The 5DIV is just short of 300 dpi/ppi (280 ppi) for a 24 x 16 inch prints.

So, do I really need more than my 5DIV for printing? I am thinking no. Even if I wanted to go really large, I could use my current 30.4 MP sensor and print up to 44.8 x 29.9 inches and still be at the 150 ppi threshold. I do, at some point, want to do a multiple frame image on a wall, you know, three prints that when combined show the whole image. I've always assumed I would do a panorama and stitch together an image for that, which would be much higher resolution. Looking at this, I might not have too.

So, other than getting caught up in a "Megapixel War" what are more megapixels good for? The thing I keep coming back too is cropping. I do not crop much for my family photos. I do not crop much for my landscape photos (sometimes just to reframe a bit). But, for wildlife that is not close...which does happen, I crop. Sometimes, I crop a lot. Could I use more resolution for wildlife? Sure...always. But, I am finding the 5DIV really has been sufficient for any print that I've made. Also, the more pixels on target you have, the better the technique you need, etc. Just because you have the pixels doesn't mean you'll see the benefit.

The next thought going through my mind, is if I am cropping for wildlife, do I really need FF? Really, it is pixels on target. For example, I scaled up the M6 II's 32.5 MP sensor to get the 82.7 MP sensor size for the "rumored high MP" sensor. But, in terms of pixel density, they are the same. In terms of pixels on target if I am cropping by 1.6x or greater, they are the same. If you think about it, taking a 500 mm f/4 lens on a FF 82.7 MP sensor and crop it down to 32.5 MP, it will even have the same bokeh and same resolution as that same 500 f/4 lens mounted on the M6 II. By cropping, you loose the benefit of FF. So, I am beginning to see the rational of why several wildlife photographers who are constantly distance challenged prefer crop sensor cameras. Granted, if you aren't distance challenge....FF.

As for the argument I've heard that more MP "is just memory and memory is cheap." Yeah, but it is also slower processing time (probably the biggest issue). Your cards fill up faster and I am typically keeping 6,000 to 10,000 images per year. That memory adds up to typically 250 to 450 GB including the jpgs I create. Backups take longer and I have to buy drives more frequently, etc.

Anyways...just some random thoughts as some evening plans got messed up. Of course, I would be interested in anyone else's thoughts on this.

Thanks,
Brant

[clemmb]

In my opinion, MP is not that important unless you are having to crop a lot. I have a 1DIII(10MP) and a 1DsIII(21MP). I love both but I find myself using my 1DIII a lot. I shot my grandson's swim meet. This was shot as ISO 1250 and I enlarged it to 16x20 canvas. I was very pleased with the way the print looked.
1D3_0187-16x20v by Mark Clem, on Flickr

I am pleased with the sharpness from this 10MP camera.
1D3_0010 by Mark Clem, on Flickr

I would love to have the latest and greatest but choose to spend my money on glass. What is more important is the lens you use and the technique.
Just my thoughts.

[Jonathan Huyer]

Interesting discussion! With wildlife photography, cropping is often necessary but more MP may not always help. When an animal is far away, there could be distortion due to heat waves from the ground. So more MP would just give you a more detailed image of a blurry subject. Also more MP always means more noise, and with wildlife you are quite often shooting at high ISO to get enough shutter speed. Speaking of speed, my understanding with high MP sensors is that you need a faster shutter speed to take advantage of the inherent sharpness. So the high ISO required to do that could end up working against you. I'd be interested in other people's thoughts on this.

I would love to have the latest and greatest but choose to spend my money on glass. What is more important is the lens you use and the technique.
Just my thoughts.

Glass is definitely important! But if you want a camera upgrade, let me know! I have a 1DX II that is looking for a good home

[Minerve101]

All good points. The other point in favor of higher MP in principle is greater ability to downsample.

How often do you find marked downsampling from a higher MP sensor to b helpful? I occasionally think it helped details on distant buildings in a cityscape, but usually do not find much advantage.

[Kayaker72]

Nice pics Mark. I especially like the ape. Definitely looks sharp to me.

I do not disagree with any other points, granted, I really do not intentionally "downsample." I do it when I am creating smaller files to email people or something like that. But there is so little noise in my 5DIV, I really do not notice a difference. Granted, if I shot at ISO 25,600 or something, I might see it then (hmmm...perhaps a test in my future).

My next thoughts on this taking the R5 (which, BTW, is confirmed, but the 45 MP is still a rumor). That 45 MP, when looking at resolving power, is 1.22x my 5DIV and 1.5x the 1DX III (or II). But, if you are satisfied with the resolution of an image that fills the frame, more MP is overkill. For images where you need more "pixels on target", we essentially are talking about adding a 1.4x extender. Then there is the not all pixels are created equal argument that Jonathan was talking about. I recall tests on this forum where the general conclusion was that crop factor cameras actually provided about 1.2x more resolving power compared to 1.6x. As a crop sensor camera is essentially a subset of a high resolution FF camera, I really do not see why the same would not apply to high MP sensors.

EDIT: Another issue, but diffraction and whatever issues that will cause. Higher resolution, the lower f stop diffraction sets in at. For example, my 5DIV is f/8.6 while the M6 II is f/5.2.

[clemmb]

EDIT: Another issue, but diffraction and whatever issues that will cause. Higher resolution, the lower f stop diffraction sets in at. For example, my 5DIV is f/8.6 while the M6 II is f/5.2.

And the 1DIII is f11.5

[Jonathan Huyer]

I recall tests on this forum where the general conclusion was that crop factor cameras actually provided about 1.2x more resolving power compared to 1.6x. As a crop sensor camera is essentially a subset of a high resolution FF camera, I really do not see why the same would not apply to high MP sensors.

I hadn't heard that one before but it makes a ton of sense to me. It follows one of the fundamental principles of life that I like to refer to as the Law of Diminishing Returns

[Kayaker72]

I hadn't heard that one before but it makes a ton of sense to me. It follows one of the fundamental principles of life that I like to refer to as the Law of Diminishing Returns

Here is the thread I referenced.

Unfortunately, the link is broken to AlanF's analysis, but I recall he was taking DXOMark's P-Mpix (perceived megapixels) and comparing APS-C to FF. As the thread and Alan's analysis are a few years old, it is always possible that there have been improvements (better microlenses?). While I can not think of an APS-C camera with the same MP of a FF out of the current lineup, the 5DIV vs the 90D, if anything, should favor the 32.5 MP sensor and 3 year more modern 90D. Yet, I can still see a slight FF advantage here. So, same framing, distance adjusted, the 90D has more pixels on target, yet I'd take the 5DIV image quality over the 90D. It is getting close, though.

[Karsaa]

Once i had 5dsr in use bit over year, and i mostly shoot at nights i started to hate those mexapixels. It was so easy to mess up with northern lights images, if there was any fuzzines on the air or wind to slightly give shake to camera.

Also more megapixels the smaller the pixel size meaning less light in. Currently i am very happy to the amount of pixels and the size of them with my 5div. Will be interesting to see how the r5 gonna perform, since other options on that future body are really tempting...or maybe even the r6 since it has lesser megapixels, which could lead it to be really nice body for my purposes.

On clear summer landscapes the 5dsr was lovely body, to have the opportunity to do that cropping etc.

[Fast Glass]

Another thing to consider is getting the shot in the first place. My brother is freaky about IQ to a fault. His ideal camera would some sort of industrial camera which needs to be tethered to a computer and uses three shots and interchangeable color filters and then stick the pics together in order to get the best color accuracy possible and fine detail ect.

But what for? He is just an amateur photographer like me, I don't need 400 MP. What am I going to be taking a pic of? My cat? Down the street? A backyard bird? Until I start putting ridiculous amounts of effort into taking a shot of that level would I dream of such a setup.

I am much more interested in making a picture that wows you, learn to take an amazing pic to begin with. Obviously I want the highest IQ possible for my budget but being a birder getting that shot is first and foremost and IQ second.

Just my rambling thoughts.