Photographer Manny Ortiz must be a glutton for punishment, because he's taking on one of the most heated, ongoing, oh-my-god-will-this-ever-stop debates in the photo industry: full-frame vs crop-sensor.

You can read our more technical take on sensor size here

As usual, Manny's take is a bit more down to earth and less tech-focused than we tend to go. He simply went out shooting with his wife/model Diana and two different Sony cameras—the full-frame Sony a9 and the crop sensor Sony a6500, both 24MP—to see if he could tell a significant quality difference between the two after a portrait shoot.

A few things we will not get into here:

  • Every comparison is a 'real world' comparison. Test charts and studio scenes do not exist in some alternate dimension where the laws of physics are suspended—they, too, are 'real world' tests.
  • Full-frame has been arbitrarily defined as 'a sensor the same size as a frame of 35mm film'. Most people agree on this definition and that's good enough for our purposes, but by all means feel free to gripe about it.

Now that these two things are out of the way, click play up top to watch Ortiz' "real-world comparison" between the full-frame A9 with an 85mm F1.4 G Master lens, and the APS-C sensor A6500 with a Zeiss 55mm F1.8. To try and match depth of field, Manny shot the A9 photos at F2.8, and the A6500 photos were taken wide open at F1.8, at least for the daytime photos.

It's no surprise then that the images had roughly the same subject isolation, since Manny shot at equivalent apertures. The bokeh was better on the GM though, as the Zeiss FF/1.8 is known to have onion-ring bokeh (with green/purple fringing).

When it came time to shoot at night, Manny had to change tactics a bit and shot the A9 photos with the G Master almost wide-open at F1.8 to avoid having to crank the ISO too high. And that's where, predictably, the full-frame shots pull ahead with more subject isolation (and lower noise which you may or may not appreciate depending on viewing size). Of course, the smaller in sensor size you go, the greater the chances the noise in low light may become significant.

Here are the final photos, sans YouTube compression and in a higher resolution so you can compare for yourself:

This is not a highly technical, control for every variable style comparison, and that's good. The point Manny is trying to make with the video (and many other such videos) is that, while sensor size certainly makes a difference in various respects, other factors like lighting, composition, a good lens and more play a bigger role in the photos your client ultimately sees.

In other words: if you know what you're doing, the portraits coming from the less expensive camera will look darn near identical to the portraits coming from the other... except if you post them in the DPReview forums where your reputation lives and dies at 100% magnification.

Check out the full video up top, and skip to around the 2:15 mark to hear Manny's thoughts on this particular debate.