Mixing APS-C lenses with full frame cameras has long been considered a mistake, something you’d never want to do if you cared about image quality. But depending on your needs, it can be a smart and practical choice. The trade-offs aren’t as black and white as they first seem, and in some cases, the benefits may actually outweigh the downsides.
Coming to you from Jason Vong, this insightful video breaks down why using APS-C glass on a full frame mirrorless body isn’t the sin people make it out to be. Vong compares options like the Sigma 18-50mm f/2.8, an APS-C zoom, with its much larger and heavier full frame counterpart, the 24-70mm f/2.8. The difference is striking: the APS-C option is about a quarter of the weight, size, and price. Yes, compromises exist, but the value is undeniable if you want something lightweight and affordable. Sony’s APS-C Super 35 mode makes this pairing even more practical, cropping into the sensor to remove the heavy vignetting caused by the smaller lens image circle.
This video also explains why field of view changes depending on the sensor size, which is where many people get confused. For example, mounting a 50mm lens on an APS-C body effectively turns it into a 75mm equivalent. The same thing happens when you use an APS-C lens on a full frame camera in crop mode—it mimics the smaller sensor, so the math stays the same. While this does mean you’re losing megapixels in stills, the impact depends heavily on the camera. On a 24 MP body like the a7 III, you drop to about 10 MP in APS-C mode, which is limiting. But on something like the 61 MP a7R V, you still get 26 MP files, the same resolution as a dedicated APS-C body, making the compromise far easier to live with.
The story changes when shooting video. Unlike stills, 4K doesn’t demand a huge sensor readout. Since a 4K frame only requires around 8.3 MP, you don’t lose resolution by cropping into APS-C mode. In fact, in some cameras you gain sharpness, because the smaller crop allows for a clean oversampled image. This makes APS-C lenses an appealing choice for video shooters who value portability, especially for setups like gimbal work where size and weight matter. Vong also points out that cameras like the a7 IV and a7C II force a crop when recording 4K 60p, so having APS-C glass actually restores your wide angle options instead of taking them away. Check out the video above for the full rundown from Vong.
Fantastic video.
One of my cameras will produce 26MP files using APS-C lenses. So...if that's good enough why not use a smaller and lighter lens when appropriate?
Using lenses designed for APS-C sensors on full frame sensor bodies produces the exact opposite of what matters to me - an image file that is bright and clear all the way out in the deepest corners.
Personally, I absolutely detest the vignette look. Dark corners and edges is a gross violation of my sense of what looks right. There are some YouTube channels that intentionally apply vignette to some of their footage, and that is so aesthetically offensive to me that I stop watching videos from that channel, even though the content is extremely interesting to me.
I sometimes do the opposite of what the title of this article suggests - I use full frame lenses on APS-C sensor bodies. In my opinion, this brings out the best trait that APS-C sensors have to offer, which is super bright corners with no hint of vignette whatsoever!
I think that the real advantage of APS-C sensors is the fact that there is no ugly vignette to deal with. And I also think that the greatest downside to using full frame cameras is that there is often some vignetting, even when using the proper full frame lens.
Edges that are just a bit darker than the rest of the frame is a look that I HATE, so I would never exacerbate that horrid tendency by putting a lens with an even smaller image circle on a full frame camera.
Fullframe cameras do now have a crop mode and if the resolution is high enough you can still get decent resolution in crop mode. I don't think it is wise to suggest anyone would use crop lenses on a full frame sensor without it in crop mode. Whether you like vignetting or not, it is obvious the dark corners seen with crop lenses on a FF sensor are not at all desirable.
I think you're a bit confused. This article (and the corresponding video) isn't saying you should throw an APS-C lens on a full frame camera, and shoot using the full width of the sensor... What the article is saying is that a lot of the time, you're already shooting video on a cropped portion of the sensor, whether you realize it or not (when shooting in high frame rates or using high electronic stabilization). Modern full frame MIRRORLESS cameras also have a dedicated APS-C (super 35) mode, meant to allow you to shoot using APS-C lenses. It only uses an APS-C sized portion of the sensor, so there are not any dark corners/vignetting to worry about.
Ok. But I wasn't really meaning to respond directly to the article and it's suggestions. I just happen to be quite opinionated on the issues of sensor size and vignette, and was using the presence of this article as an excuse to "be loud" and get my opinion out there, even though it isn't a perfect fit with what the article was suggesting.