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Canon 5D Mark III vs. SL1
Resolution and High ISO Comparison
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September 2013   Canon Reviews   Canon Lenses   All Reviews

Canon 5D Mark III review

Canon EF 24-70mm f/2.8 L II review

Canon Rebel SL1 review

18-55mm STM review


Resolution Comparison

Just because I can, let's compare the sharpness, resolution and high-ISO performance of the world's best DSLR, the Canon 5D Mark III ($3,500) using the world's sharpest midrange zoom, the Canon EF 24-70mm f/2.8 L II lens ($2,300, or $5,800 total) to Canon's cheapest: the Canon Rebel SL1 ($600) and 18-55mm STM kit lens ($249, or $699 total as a kit with the SL1).

These images below are but tiny crops from the centers of each image. If these are about 6" (15 cm) wide on your screen, the complete prints from each camera would be 52 x 35" (4.3 x 3 feet or 1.3 x 1.0 meters) at this same magnification:

Roll mouse over to compare. For you without mice, here's the other image:

Canon SL1


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Summary and Analysis       top

As far as I'm concerned, I see no significant difference between the two. Remember, these are extreme blow-ups from prints many feet wide. If I showed the complete, uncroppped images (which I don't here) or showed them at a more reasonable size more like the sizes at which people actually print, they would be completely identical.

Therefore as I always say, the more expensive camera only costs more and weighs you down more. Sure, I can force differences under unreasonable circumstances for the sake of spicing up my reviews, but for actual shooting, it doesn't matter what camera you use.


Technik         top

I shot these each in my usual settings: 6 sharpening, +4 saturation, and NORMAL LARGE JPG, program auto exposure and Auto ISO and Auto white balance. Each camera chose f/8 at 1/200 at ISO 100.

I set each zoom for the same angle-of-view to take the same picture, about 35mm for the full-frame 5D Mark III and about 22mm for the SL1. I downsized the 5D Mark III image by about 10% to compensate for the slightly different image sizes (5,760 vs. 5,184 pixels wide) so the two images match for comparison. This shows exactly what you'll see with each image printed about 52 x 35" (4.3 x 3 feet or 1.3 x 1.0 meters) of the same subject.

If you don't understand the need to keep the images the same size to make a valid comparison, you're welcome to redo this test yourself and use Canon's 1D X instead of the 5D Mark III. The $6,800 1D X has exactly the same resolution as the $599 SL1: 5,184 x 3,456 pixels, so no resampling would be needed, and each would be identical.

Since the exposure and internal camera processing vary a little from model to model, I had to lighten the 5D Mark III image a bit, and added a tiny bit of sharpening (50% at 0.2 pixel radius smart basic more accurate) to the SL1 image to create the same texture. Regardless of how much sharpening is added, you never can extract detail that isn't there; this was done to keep the texture and contrast of each image close so you could compare them better.


High ISO

Let's see how they look at ISO 6,400:

Canon 5D Mk III at ISO 6,400

Canon SL1 at ISO 6,400

I see that the 5D Mark III has a little less noise, but is it really worth the effort to haul the 5D Mark III and its larger lenses all day just for the one or two shots you might have to make in the dark? Heck, the SL1 has a flash and the 5D Mark III doesn't, so where is this going anyway?

Let's crop-in to the same crazy resolution as the top and see what sharpness difference there is at ISO 6,400:

Canon 5D Mk III at ISO 6,400

Canon SL1 at ISO 6,400

Aha! Here we see the only real difference. If you're going to shoot in the dark and then print 5 five feet wide and then look at it from this close, yes, the 5D Mark III is a bit sharper.

This is because the smaller sensor of the SL1 demands more noise reduction to control the noise, and this noise reduction robs some sharpness.

ISO 6,400 is insane anyway. At ISO 6,400 I can shoot the stars in the sky or under moonlight,  hand held, so I wouldn't worry about it — unless you really want to buy the 5D Mark III, which is a wonderful camera.

At ISO 6,400 in room light indoors where I shot these, I shot at f/8 and 1/2,000 second! ISO 6,400 clearly isn't needed; ISO 100 would have been plenty to shoot at f/4 and 1/125.


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Mr. & Mrs. Ken Rockwell, Ryan and Katie.


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