We compare the technology of EF vs RF lenses here side by side in terms of their specs and also explain why the newer generation performs better than previous lenses.
By the 1980s, the transition from manual focus to autofocus lenses started to reshape the industry, culminating in the launch of the EF mount in 1987.
Later, even better technologies came along, like the split-image rangefinders for the optical viewfinder and the mechanical shutters. These once-revolutionary mechanical lenses of that time saw another seismic shift with the arrival of EF, a.k.a. electro focus lens.
Fast-forward three decades, RF (reimagined focus systems) came along to match the newer generation of mirrorless cameras, which reset the bar for the entire industry as of today. This transition often sparks a debate about EF vs RF lens as both newcomers and veterans of this niche are interested to know how both these lens systems stack up together. Here is a quick comparison of how they look in terms of specs:
1. FFD dictates Optical Quality
The technical term flange focal distance is the length between your camera's lens mount and its image sensor. This distance significantly impacts the final quality of the pictures you take with your camera. The older EF lens systems are designed with this distance to be at 44mm, which is quite a lot and is so to accommodate the mirror box found in SLR cameras.
This distance makes it harder to create compact camera bodies and also doesn't help to minimize camera distortion in wide angles. On the other hand, the newer models correct this issue as RF lenses are now designed with a much shorter 20mm flange distance since there are no mirrors in them.
You might think it's not that much of an improvement, but this is the most significant factor in this EF vs RF lens comparison, as improvement in FFD for RF lenses brings much better optical performance, lens size, and adaptability. This new breed of lenses also delivers much better image stabilization in the field and are light weight. You also get support for in-body image stabilization.
It is worth mentioning that the aging EF lenses can still be used with new RF camera mounts using adapters, but the new RF lenses are not back-compatible with previous mounts due to their design limitations. So, your new shiny RF camera can still rock the EF lens with adapters if you happen to be investing in EF systems in the past years but expect slower autofocus speeds.
2. Faster Data Speeds!
The RF mount introduces a 12-pin electronic contact system, compared to the 8-pin setup in most EF lenses. This upgrade allows for faster and more precise communication between the lens and the camera body, improving autofocus performance and real-time lens corrections. Simple rule: more pins, more conduction, faster data transfer between the lens and the camera body. The result is that your RF lens will give you much better performance when autofocusing with precise image stabilization.
3. RF are much lighter:
Another important consideration in our EF vs RF lens comparison is the convenience of use, especially if you carry your gear around. RF lenses can be more compact than their EF counterparts, particularly in wide-angle and standard zoom lenses. However, some high-end RF primes, like the RF 50mm f/1.2L, are actually larger due to their more complex optical designs.
You will find RF lenses to be much more compact than EF, but there are some exceptions too; for example, the 50mm f/1.2 RF mount lens in the market is slightly larger as compared to EF counterparts due to their advanced inbuilt optical hardware that takes a lot of space.
4. Upgrades in Mechanics:
The EF lenses use USM & STM motor systems for autofocusing, and the new RF lens uses an upgraded version of these motors called the Nano USM & STM. These systems are much smoother and superior, thanks to their higher data transfer speeds and improved mechanical designs. You get better tracking accuracy and faster auto focus while keeping them silent as compared to EF, which is less optimized, especially for video shooting.
Is EF Lens Worth keeping?
Although this entire article was biased towards the newer RF lenses due to their superior data communication and mechanical advancements (leading to better autofocus speed, image quality, etc), EF lenses still deserve some of your love.
If you have previously invested a lot in the EF lenses & want to save money for the future, then just buying an RF adapter can still be a great option. The OEM RF adapters are known to retain full autofocus and stabilization, and you still don't have a direct RF equivalent of many popular professional lenses, so EF can still be your buddy.
But you will have to deal with bulky lenses, and also, you will be an outlier in the industry, which is now moving towards mirrorless camera systems. As we finish off our EF vs RF lens comparison, it is now time that you decide whether you want to keep your beloved EF lenses or move towards RF. Of course, newer generations of RF lenses are now more common and are here to stay, so an upgrade is imminent.
If you plan to move from your EF lens collection to the ones with native RF mount compatibility, then prepare yourself for significant price tags unless you opt for the saturn 35mm 1.6X full-frame anamorphic lens. Designed specifically for people upgrading to RF mounts who do not want to compromise performance while being light on your wallet and your camera body (it weighs below four hundred grams!). Moreover, it can be used both handheld and with a gimbal, and it is a great choice for filmmakers.