Sensor Showdown

I previously wrote about camera sensors – how they work, sensor size, and a comparison of various sensors in cameras that I’ve owned plus a couple that I haven’t. What I didn’t do there was directly compare photos from my cameras. I suspect that at web publication size it’s going to be difficult to tell the difference, but let’s find out.

I found a couple pairs of pictures among my thousands of photos of similar, though not exactly the same, scenes, taken by 1) the Fujifilm FinePix XP55 (point and shoot) vs. the Canon Rebel T6 (APS-C DSLR) and 2) the Samsung Galaxy Orbit J3 (my mostly functioning phone) vs. the T6. To compare, I’ll be showing both the full photo and some crops at 100%. Normally you don’t zoom in to 100%, because 18 or even 12 MP is plenty for the majority of applications, especially scrolling through social media on your phone, but for the purposes of this exercise we’re doing it.

First up, we’ll look at the Huron River at one end of Gallup Park on the Border to Border Trail. The point and shoot picture was taken on the last day of 2021 when I was taking advantage of 40 degree (F) weather to go for a bike ride. The DSLR photo was taken on the first day of February when it also hit 40 F but we’d had enough cold weather to partially freeze the Huron and there was some snow on the ground. So obviously the conditions were different, but the framing is very similar (the 35mm/full frame field of view equivalents¹ are 28 mm and 28.8 mm for the XP55 and T6 respectively, so essentially the same). In terms of the other settings, the XP55 used a larger aperture, but with such a short focal length more or less everything is in the range of acceptable focus. With the T6 at f/8 and focusing on the bridge in the background, the depth of field extends to all the way from infinity up to a couple meters in front of me. Both shutter speeds should have been fast enough to avoid camera shake, and the ISOs were the same.

Fujifilm FinePix XP55, 5 mm, f/3.9, 1/150 s, ISO-100

Canon Rebel T6, 18 mm, f/8, 1/100 s, ISO-100

Overall, I think the T6 photo is sharper, and it retained better texture in the sky, which could have been because of the different weather conditions, but I would expect the T6 to have a better dynamic range (the maximum different between light and dark areas that a camera can capture in a single exposure – for the T6 it’s 10 stops; the human eye sees about 21 stops) than the XP55. If we zoom in all the way, the front tree is decidedly sharper on the T6, and if we look at the railing section, the T6 photo is both sharper and less noisy.

XP55 (left) vs. T6 (right)

Next I have a couple photos from separate trips to the library. Again, the T6 photo is overall sharper, which can be seen if I zoom in all the way and try to read some of the book titles. It’s not hugely obvious in the crops below, which proves my point about web resolution. The other part of the photo where the T6 looks sharper than my phone is actually the overhead light fixture. Again, not super obvious below, more obvious on my computer at 100%. The one point that the phone comes out ahead on is its significantly larger aperture that lets in something like 8 times (3 full stops) as much light as the maximum aperture on my DSLR’s wide angle lens, allowing for a much lower ISO. It’s not as noticeable around the books, but I can kind of tell zoomed in to some of the areas that are more monotone in color that the DSLR photo is noisier.

Samsung Galaxy Orbit J3, 3 mm, f/1.9, 1/40 s, ISO-125

Canon Rebel T6, 18 mm, f/5.6, 1/60 s, ISO-1600

Phone (left) vs. T6 (right)

To conclude, yes, a sensor with a 10-30x greater area outperforms a ten year old point and shoot and a Tracfone. However, unless the photo is obviously not in focus (quite possible with my phone photography), you may not be able to tell online, and probably not with small prints either. Where people would be able to tell in practical applications (i.e. not zoomed in at 100% on a computer looking at individual twigs on a tree) is with cropping and larger prints. Lugging around a DSLR is worth it for me for the improved low light performance, ability to change camera settings, and intentionality of framing a photo, but if you only ever look at photos on your phone and rarely print anything, you can probably save your back and your wallet with a halfway decent phone.

¹Crop factor can get confusing, but the relevant information here is that it’s based on sensor size compared to the “standard” 35 mm or full frame format. The T6 has a crop factor of 1.6 and the XP55’s 1/2.3” sensor has a crop factor of 5.6 so that focal lengths of 18 mm and 5 mm respectively give the same field of view as a 28 mm lens on a full-frame camera.