Mark Sturtevant Loc: Grand Blanc, MI

I am doing my customary 'research' before making a major purchase of camera equipment, and here I have run into a small puzzle that I would like to ask the Hoggers about. I am shopping for a used full frame Canon EOS body to upgrade from my T5i crop sensor body, and here I want to get a ff body that gives me the best image quality. I don’t much care about other perks. WiFi? Never use it. Articulating touch screen? Nice features on my T5i but I can live without them. What I really want are low levels of sensor noise while keeping the cost under $800. That means an older body.
I am looking at two camera bodies right now: the Canon 5d Mark II versus the Canon 6d (which is newer by several years). So here are the specs of these cameras according to Canon’s own web site.

5d mII:
21.1 megapixels (effectively) on a 36 X 24mm sensor. This means 20,736 pixels per square millimeter. Feel free to check my math.

6d:
20.2 megapixels on a 35.8 X 24.9mm sensor. This should mean 22,660.47 pixels per square millimeter.

The 5d has larger pixels on the sensor. But how should that translate to sensor noise under comparable conditions? I was sort of anticipating/hoping that the 5d would show less sensor noise, and that would be nice since it is older and therefore cheaper. But according to data from the dpreview web site the 6d does better in this area. Below are jpeg pictures comparing sensor noise in the 6d, 5dmII, and the 700D (which is the same thing as my t5i) at ISO 6400. You can see that noise reduction is set to be off. Turning on noise reduction reduces noise but does not change the comparison. Lower ISO values also does not change the comparison. The 6d has the least noise, while the t5i (700D) crop sensor has the most noise. I was of course not surprised about the crop sensor! I have an idea about why the 6d does better than the 5dmii, even though the 6d has smaller pixels, but I would like to solicit opinions from my fellow Hoggers.

As an added puzzle, the second and third pictures show there is a lot more noise when shooting in RAW. I was surprised to see that since I shoot in RAW. I would like to learn more about that!

I am open to considering other bodies like a high end crop sensor. But it should be Canon, compatible with my lenses, and be under $800.

RichardTaylor Loc: Sydney, Australia

The reason the 6D has better noise performance than the 5DII is that it is a newer model body.
From personal experience newer (not all) models perform better than some older models even if the sensor size is smaller.
My Canon 70D (C 2013) runs rings around my Canon 5D (C 2005).

Depending on what you are shooting the flipout, and rotating, screen can be very handy.

BassmanBruce Loc: Middle of the Mitten

Mark, don’t know what you think about DXO tests but here is one if you’re interested:

https://www.dxomark.com/Cameras/Compare/Side-by-side/Canon-EOS-6D-versus-Canon-EOS-5D-Mark-II___836_483

Best of luck whatever you decide.

TriX Loc: Raleigh, NC

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Mark Sturtevant Loc: Grand Blanc, MI

70D... hmmm. I had thought of it long ago but had not recently gone back to it, as I was fixated on ff. I expected the answer to the 'mystery' could be the age of the body, as you say.
Anyway here is the comparison that includes the 70D. At least under dpreview tests, it does not seem better. But I am wondering if dpreview could be wrong. Had wondered on that before. Admittedly too these are some pretty high ISOs. I never need to go above ISO 800 on my crop sensor since I almost always shoot outdoors in the daytime. But I am using these higher ISOs to push the comparisons.

Mark Sturtevant Loc: Grand Blanc, MI

Thank you. I think (?) this DXO comparison shows the 6d is a bit better than the 5dmii in this regard.

(Download)

Mark Sturtevant Loc: Grand Blanc, MI

Mayybeee. But there is also this sweet sweet lens I am coveting....

TriX Loc: Raleigh, NC

Just a thought... I can tell you from extensive experience that the 5D3 will produce very acceptable results at ISOs to 12,800 if that’s your need/goal. Sorry, but I can’t speak to the 5D2, although the photons to protons DR chart and low noise tabulation shows that it is very close to the 5D3 in performance.

repleo Loc: Boston

Mark,
I think you are looking at the wrong chart on DXO. The chart you posted is for manufacturers stated ISO vs Measured ISO. In other words it refers to the accuracy of the ISO reading on the camera.
For Noise vs ISO, look at the Signal to Noise Ratio (SNR 18%) chart. That shows the 6D beating the 5Dmii by about a half to one full stop. The higher the SNR, the better. For explanation of the DXOmark testing and scores see here: https://www.dxomark.com/dxomark-camera-sensor-testing-protocol-and-scores/

(Download)

Notorious T.O.D. Loc: Harrisburg, North Carolina

What lenses do you have and will they work with a FF body, EF mount? I am not sure what exactly you are seeking if you don’t need to go above ISO 800. Perhaps your money would be better spent on better glass.

Modbuilder

+1 on the flip out view screen

steve49 Loc: massachusetts

In a technical product like this newer will be better 99% of the time.

Mark Sturtevant Loc: Grand Blanc, MI

@ repleo: Thank you. 👍

@ Notorious: My lenses are for full frame, and they are all L lenses. Sort of odd to have this fancy glass on a consumer grade camera body right now.

Blurryeyed Loc: NC Mountains.

Mark, if you don't care about advanced features the 6D is an excellent camera and had the best noise performance of all the Canon's when it was produced. I will add only that proper exposure helps a great deal with noise performance.

Notorious T.O.D. Loc: Harrisburg, North Carolina

That’s great to have good glass. We all have to move toward where we want to be as best we can given our druthers and means. My first 1D series was a 1D MkIII, but even though it was an older model when I got it you can take nice photos with it especially in good light. And the resolution is fine for posting online too. Do what you can to move towards your goal.

One thing you can do is look on Flicker for photos taken with the lens and body you are interested in by using the search tool. I have done that before.