The full frame vs. APS-C debate has been running for years, and most people land in the same place: full frame is better, APS-C is smaller, end of story. But that conclusion skips over some real nuance that changes how you should think about both systems.
Coming to you from Pit Haupert, this methodical video works through the full frame vs. APS-C comparison by actually testing the two systems rather than just reading spec sheets. Haupert starts with image quality, specifically resolution and dynamic range, two areas where full frame supposedly dominates. He underexposes both systems by four stops and recovers the images, and the noise levels are close enough that the difference is hard to call. Where full frame does pull ahead in a real way is low light performance at matched settings, because APS-C is effectively a crop of the full frame image, which magnifies noise and makes it more visible. But here's where it gets interesting: Haupert shows that if you shoot APS-C with a brighter lens, say f/1.4 at ISO 1600 instead of f/2 at ISO 3,200, the gap largely disappears. The lens is doing as much work as the sensor.
The background blur comparison follows the same logic. Put a Sony 85mm f/1.8 on a full frame body and a Fujifilm 56mm f/1.2 on APS-C, and the results are comparable. Adjust for equivalent focal lengths and apertures, and you can match the look across sensor sizes. The concept Haupert keeps returning to is equivalence: for most real-world shooting, you can tune your APS-C setup to match what full frame produces. That's a more useful frame than debating megapixels in the abstract, and it reframes the whole question around what you actually need to achieve a given result.
Where Haupert's argument gets genuinely surprising is in the downsides of APS-C he identifies, and they're not the ones you'd expect. The "aperture ceiling" problem means that to match a full frame f/1.4 lens, you'd need an f/1.0 on APS-C. Those lenses barely exist, and when they do, optical quality often suffers. Then there's the size paradox: APS-C lenses built for equivalence often end up larger than their full frame counterparts. He compares the Viltrox 27mm f/1.2 for APS-C at around 560 g against the Viltrox 35mm f/1.8 Evo for full frame at only 360 g. Same purpose, meaningfully different weight, with the APS-C lens coming in heavier despite being designed for the "smaller" system. The practical implications of that tradeoff are worth sitting with before you assume APS-C automatically means a lighter kit.
Check out the video above for the full breakdown from Haupert, including his take on when equivalence stops working and why he's switched between systems more than once.
4 Comments
How about the one area where I think full frame actually does pull ahead -- astrophotography. As a budding astrophotographer with an APS-C camera (that I truly love!), it seems like my full frame counterparts seem to pull in more light with less noise. Of course, maybe it's just me, or that I'm shooting with a 40 megapixel sensor, and supposedly high megapixel sensors are at a disadvantage for astro (smaller "light buckets" and all).
I watched the video and a lot of points were made and yes compares to both. I started with digital back in the 2000's and went APS-C in 2010 with the Canon T2i then to full frame in 2014 with the A7SM1 mainly it was the only model that does 5 at +/- 3EV, it was the HDR days with DSLR's had no idea what I was getting into till it was all the rage for astro.
Not many are young enough to have all that and use all a lot or even do most have their images of all the times used. Also Software to edit any thing was so expensive only the big magazines/papers and etc. could afford like PS and Lr were both about $800 each as well as the same for each full update, my T2i with two kit lenses cost $800 so us who used/worked/hobbyists had to use Canons editing software but was not available when the next T3i came out and yes that is when I went to the under $100 SW's.
Enough hard learning stories!
One point not made is all lenses for APS-C were the labeled but most never made the conversion But no big deal what ever you saw in the eye piece or LCD is what you captured with no heart burn for it was what you had.
A second point is they were DSLR's with a mirror, hey so what, but also compared to todays mirrorless ISO was topped at ISO 6400 or to 12800 if need be. My Sony A7SM1 went up to 409600 but was real noisy but most that high was for video where you can capture the stars above but never needed anything above 6400 and even that night was like day. All in all I still have and use sometimes and is a great camera with great images. In my thoughts any camera is good for life, for the normal user, as well as the lenses, Never call them cheep just low cost please!
Also if I give my say on noise of the early APS-C cameras as well as the old point and shoot with in camera telephoto magnification there is little to none and and image stabilization was and is great. I used a FUJIFILM WP Z on a cruse, my first, and still all images did not need any SW help.
image with MW was way before I even knew about MW's using Canon T2i and EF-S 10-22 at 10mm (16mm) ISO 6400, SS 25 sec, f/3.5. Did not notice till years later yes a little editing to bring it out but all I was doing was waiting for the moon to come down next to a lighthouse.
Sunset a 3 frame +/- 2EV on Canon T2i. @ f/8 EF-S 18-55 mm @18 mm. PP in Oloneo
Faces in USS Arizona oil with Vivitar Vivicam 8300s no editing the photo store printed and pointed out years before a person became famous for a like image. back then 2006 it was like film just take the SD card. If you ever go give it a try!
Oloneo less than $80 was my SW at the time fun times for hobbyist also!
I stared with APSC in 2008 and the only thing I changed was from 6 to 24 megapixels. Seems a 4x increase was enough for me. My lens is still from 2008. When I compare this to full frame 35mm back in 70s and 80s there’s just no reason to go further.
This topic is so annoying. Does FF get better IQ? Sure. Does it matter in most situations for 2026? No. It’ll always hold a IQ advantage (comparing two cameras from same generation, same brand). But the argument over more background blur, and better noise performance is really only noticeable in comparison like this where you put them side by side. I have personally done this on my R6II vs R7 (using a L lens on R6II vs Sigma RF lense on R7), and while side by side it’s noticeable zoomed in at 100-200%, I came away impressed that the R7 with a MUCH smaller and cheaper lens performs so well. As for the lens size comment in the article, my Sigma RF 10-18 2.8 and 18-50 2.8 weigh about 500g TOTAL. No chance there’s that equivalent for FF. So, the R7 and Sigma lenses usually go on trips, while my R6II sits at home collecting dust when I go on trips. Never mind the cost factor. The R6II is 50% more money, and similar lenses will cost twice what the two Sigma lenses cost. I don’t see a day that I won’t have APSC cameras.