Glass Got Gooder

It was when the Canon EOS-1Ds Mark II came out that camera magazines started talking about it. That full-frame 16MP sensor had enough resolution to let you know if your budget lens was a little soft in the corners. Most 35mm film has a resolution roughy equivalent to 6MP or so, and early DSLRs had smaller APS-C sensors that only used the center of a full-frame lens's image circle, where things are sharper.

"Weaknesses? Well none that were really engineered into the camera, but the EOS-1Ds Mark II is a very unforgiving camera when it comes to lenses. That ultra high resolution and full size 35 mm sensor mean that not only does the camera use all of the glass in a lens but it can reproduce it in minute detail, warts and all. A direct A-B comparison with a cropped sensor camera (such as the Nikon D2X) soon demonstrates that you really have to be careful selecting your lens and stopping it down sufficiently so as to avoid soft corners. You'll also have to (generally speaking) spend more on your lenses than you would for a cropped sensor camera."

When the 36MP Nikon D800 came out, it officially became a Big Deal. A big enough deal that Nikon put out a list of recommended lenses. With cameras like the D800 or the 50MP Canon EOS 5DS, you want to keep shutter speeds fast, too, because the tiniest bit of camera movement will show up at those resolutions.

The EOS R came out in 2018 and has a 30MP full frame sensor. It uses the new RF-mount lenses, and lens design has really come a long way. The RF 24-105mm f/4-7.1 IS is an inexpensive zoom available in a kit with some of the mid-price mirrorless Canons (or by itself for a little over four hundred bucks, or less than a third of the cost of the 24-105mm f/4L pro zoom) and it seems to do pretty okay even with that high resolution sensor.