EOS R, EF-S Lens Crop Loss of Megapixels

[mindawoo]

I currently using a t2i Canon 18 mp crop sensor camera, According to Canon, when EF-S lenses are used on the EOS R camera the camera "will automatically produce cropped 11.6-megapixel images that match the smaller image circle of EF-S optics." So a 30mp camera effectively is now 11.6mp, much less than what I have with my current set up. I am looking to move to full frame so the EOS R seemed to be the way to go until I hit this stumbling block. I can't afford to buy both the camera and new lenses at the same time but plan to upgrade lenses slowly as budget permits. Is this something I should be concerned about or will having a better sensor and newer technologies make up for the loss in megapixels?

[ebiggs1]

" So a 30mp camera effectively is now 11.6mp, much less than what I have with my current set up."

Actually you are only mathematically correct but not photographic.  The pixel density is still exactly the same.  The resulting photo will exhibit the same IQ.

[CarlG]

You know I didn't think about it in those terms. Very good point! I have an EF-S 10-18 that is incredible on my 80D I need to try it on the R. Thanks for making that point.

[mindawoo]

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@ebiggs1 wrote:

" So a 30mp camera effectively is now 11.6mp, much less than what I have with my current set up."

Actually you are only mathematically correct but not photographic.  The pixel density is still exactly the same.  The resulting photo will exhibit the same IQ.

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If I am understanding you correctly then this would impact how large a print I can make without losing print quality?  For example, according to this guide Megapixel Chart  I should be able to print up to a 9 x 14 at 300 ppi as long as I didn't crop much. And, according to the comments, with some photoshop tricks and using slightly less ppi, I should be able to achieve even larger prints without sacrificing quality; how far I can push this is determined more by the quality of my sensor and lenses.  What about the statement made in the comments regarding sensors; that, for example, a "larger 6MP sensor will of course produce better images than a smaller 6MP sensor of the same type."  What does this mean exactly? That full frame sensors are better than crop?

[RobertTheFat]

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@mindawoo wrote:

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@ebiggs1 wrote:

" So a 30mp camera effectively is now 11.6mp, much less than what I have with my current set up."

Actually you are only mathematically correct but not photographic.  The pixel density is still exactly the same.  The resulting photo will exhibit the same IQ.

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If I am understanding you correctly then this would impact how large a print I can make without losing print quality?  For example, according to this guide Megapixel Chart  I should be able to print up to a 9 x 14 at 300 ppi as long as I didn't crop much. And, according to the comments, with some photoshop tricks and using slightly less ppi, I should be able to achieve even larger prints without sacrificing quality; how far I can push this is determined more by the quality of my sensor and lenses.  What about the statement made in the comments regarding sensors; that, for example, a "larger 6MP sensor will of course produce better images than a smaller 6MP sensor of the same type."  What does this mean exactly? That full frame sensors are better than crop?

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Yes. The larger the pixel, the more light it can collect, and the more accurate it can be about what photons it sees relative to its neighbors. And full-frame sensors, except in the highest resolution cameras, have larger pixels. Which represents an improvement in image quality. But the effect is greater on low-light performance than on resolution: 6 MP is still 6MP.

[wq9nsc]

Bob explained that well.  For a given level of technology, the larger the individual sensor cells the better the low light performance.  When low light performance goes down, in addition to noise you also run into the issue of color shift and loss of color vibrancy as processing compensates in an effort to reduce apparent noise.  My 1DX 2 and 1DX perform well in low lighting sports situations but I would love to to experiment with how an 8 Mp version using the same sensor technology with resultant much larger sensor cells would perform.

I remember reading a funny article quite a few years ago about a professional photographer set up to take photos at a road rally and two amateur photographers were snickering about him using his then 4 year old original Canon 1D (with all of 4 megapixel resolution) while they had their much newer multi-megapixel consumer grade cameras.  A pair of cars raced by and the pro captured several nice images while they had nothing but garbage.

The number of megapixels is an easy metric that the average consumer thinks he/she understands but it is only one part of the chain of characteristics leading to good image quality.

Rodger  

[CarlG]

Essentially it's like this:

An APS C sensor is 24mmx16mm = 384 sqmm a 18mp sensor has 46,875 pixels per sqmm

A Full Frame Sensor is 36 x 24mm = 864 sq mm a 30mp sensor has 34,722.22 pixels per sqmm

That being said the full frame pixels are 1.3 times LARGER than than the APS C

What this means is the full frame sensor pixels are able to gather more light and image information than the APS C therefore leaving you with a somewhat higher quality image per pixel. very handy in low light.

That being said the high end EOS 1DX is a 20.2mp full frame sensor and that sensor has 23,379.629 pixels per sqmm. which means these are even larger (2 times an 18mp APS C) and therefore gather more light and more data quickly. This why you can get such high frame rates from EOS 1DX.

All of this being said there is no PERFECT camera for ALL instances and ALL budgets. 11.6mp is 11.6mp....however those pixels can vary in size and light gathering capabilities.

If I have made an error here someone please politely point it out. I hadnt thought about this in depth until ebiggs pointed it out to me....amd I thnk him for that.  I hope this helps.

[Waddizzle]

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@CarlG wrote:

Essentially it's like this:

An APS C sensor is 24mmx16mm = 384 sqmm a 18mp sensor has 46,875 pixels per sqmm

A Full Frame Sensor is 36 x 24mm = 864 sq mm a 30mp sensor has 34,722.22 pixels per sqmm

That being said the full frame pixels are 1.3 times LARGER than than the APS C

What this means is the full frame sensor pixels are able to gather more light and image information than the APS C therefore leaving you with a somewhat higher quality image per pixel. very handy in low light.

That being said the high end EOS 1DX is a 20.2mp full frame sensor and that sensor has 23,379.629 pixels per sqmm. which means these are even larger (2 times an 18mp APS C) and therefore gather more light and more data quickly. This why you can get such high frame rates from EOS 1DX.

All of this being said there is no PERFECT camera for ALL instances and ALL budgets. 11.6mp is 11.6mp....however those pixels can vary in size and light gathering capabilities.

If I have made an error here someone please politely point it out. I hadnt thought about this in depth until ebiggs pointed it out to me....amd I thnk him for that.  I hope this helps.

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Eh, I think you’re on the right track, but your math and conclusions are a little fuzzy.  You are conflating pixel density with pixel size, which is incorrect.  For example, the 6D uses very large pixels for 20MP resolution.  The 6D2 has 26MP resolution on the same full frame sensor size, but the pixel size is just slightly smaller than those in the 6D.

The size of the individual pixels on different Canon sensors can be found in the specifications.  In the case of the 6D2, engineers were apparently able to reduce the space between pixels.  They were able to fit 30% more pixels within the same area.

[ebiggs1]

"..."larger 6MP sensor will of course produce better images than a smaller 6MP sensor of the same type." "

Some how we got off of resolution and onto low light performance? I am going to stick to resolution for now but we can discuss low light if you want. First you can not just compare sensors without considering the whole camera. For instance any newer sensor is going to out perform most older sensors. Make sense, as they should as technology advances. A 6MP sensor made with 2019 tech should be better than a 2009 6MP sensor. The rest of the innards of the camera will also come into play. The sensor type is also a consideration, BSI (Back Side Illuminated) CMOS or CCD. An 18MP Rebel has pixels that are approx. 4.3 microns and my 18MP 1DX they are 6.9 microns. As you might conclude the Rebel is going to have higher IQ because the pixels are smaller and there is going to be more on subject. This starts another debate whether it is better to shoot with a crop sensor with smaller pixels and enlarge it to the same size as the FF or just use the FF in the first place.

The more pixels you put on a sensor, the smaller the pixel will be. Correct?  An 18 megapixel sensor will have smaller pixels than a 12 megapixel sensor, assuming both sensors were exactly the same size.  However there is nothing saying the pixels have to be crammed as tightly as possible, sometimes they are not but that is a general rule of thumb. The sensor type is also a consideration,  BSI (Back Side Illuminated) CMOS or a CCD sensor.

General rule a smaller sensor is not going to be able to make as big of a print as an equivalent larger sensor when viewed at reasonable distances.  The viewing distance must also be considered. And the most confusing part is DPI. Cameras and Photoshop do not have DPI.  Only printers have DPI. Cameras always shoot at whatever resolution they were made with.

"All of this being said there is no PERFECT camera..."  You are correct, sir!

[CarlG]

Yes I was trying to be too simplistic in my reply. Utilizing very basic APS C dimensions vs Full Frame and not from Canons specs. You are of course correct. Just imagine the sensor from the R in a 1DX mirrorless with dual Digic 8 processors! Fun times. I was though trying to be simple in an explanation 😂

[hearkg]

Please create a firmware upgrade to allow us to use the whole sensor with ef-s lenses if any of the people at Canon Read this.

I know that the image circle of an ef-s lens can't cover the whole sensor. But wider lenses are capable of producing very good macro images when mounted backwords. I have a 100mm macro lens but I really want to use my old 18-55mm kit lens as a great macro lens because it produces larger magnification than the 1:1 100mm macro lens.
please allow us to use the whole sensor with ef-s lenses. 🙏🥺🙏🥺🙏

Make the firmware to change the mode to 1.6x crop whenever an ef-s lens is attached to the camera but let us change it back to full sensor mode in the menu, so the people who know about this will change intentionally and no one will complain about the huge vignette when mounted in the foward direction.
Please.......