Viltrox AF FE 28mm f/4.5 VCM ASPH ED Lens Overview

Viltrox asked me if I wanted to take a look at this unique compact autofocus full-frame prime lens with a focal length of 28mm and a fixed f/4.5 aperture for Sony E-mount cameras. Viltrox agreed to my standard collaboration terms before sending me the lens. 

 

In the video I talk about features, how it works in practice, and show photos I had taken on a photo walk with the Sony a7S as well as the APS-C a6000.

 

The front of the lens.

Check out my newer article where i take the lens on a photowalk with the Sony ZV-E10 camera.

Key Specifications:

• Focal length: 28mm
• Aperture: constant f/4.5
• Field of view: 73.42 degrees on full-frame
• Lens elements: 6 total (2 ED low-dispersion, 2 aspherical)
• Focal range: 0.32m to infinity
• Magnification: 0.11x
• Focus motor: VCM type
• Weight: Approximately 60g
• Size: 60.3mm x 15.3mm
• Port: USB-C for potential future firmware updates

The back of the lens. Take note of the USB-C port for potential firmware updates.

Build Quality & Design:

The build of the lens is a mix of plastic and metal. Mostly plastic in the front and metal in the back. The plastics feel solid. It’s a very compact lens, and on some Sony cameras like the a6000, it might even fit in a pocket. At least a cargo pants or coat sized one. 

One of the best things about this lens is that it covers a full-frame sensor while still maintaining autofocus and a decently wide aperture.

After I had already published my video, I took a look at what others had to say about the lens. Christopher Frost noticed that the back element of the lens can extend very low. Nearly or slightly past the mount, so you should be careful with that when setting the lens down! Use the cap or place it front side down with the lens cover closed.

A quick photo I took to show how low that back element extends into the mount.

Another consideration will be dust and dirt in regard to the built-in lens cover with the related toggle mechanism. Be careful to make sure it is clean before sliding it open or closed.

Autofocus and AF in Video:

Single shot AF-S autofocus did function decently enough in good lighting and many of the photos on my photo walk were focused where I had expected them to be. The lens felt like it focused a bit faster on the a6000.

Continuous autofocus didn't work well on either camera, though the a6000 was again a bit better with locking focus. I'd describe the lens as "hyperactive" in AF-C modes. When it would normally gain focus in AF-S, it would continue racking back and forth in AF-C mode. At least with what I assume is pre-release firmware, I'd consider the lens AF-S only with this earlier generation of Sony cameras. Hopefully autofocus will improve on this generation of Sony cameras with a future firmware update.

I was able to set the camera to manual focus and assign a custom button to "AF/MF Control Hold" to mimic AF-S. Also, assign another button to "Focus Area" so that the focus point can more easily be adjusted. At least with flexible spot mode which is what I tend to use. 

You can also pause autofocus when it is in AF-C by default with the button inside the AF/MF AEL toggle switch on the a7S. 

Testing it out in video mode, I used this lens for some b-roll footage on the a7S. The clear image zoom feature on the a7S was a nice bonus, letting me adjust framing of the video to get more detail on my subject.

B-roll with the a7S, Viltrox lens, clear image zoom, and that focusing technique. Recorded into an Atomos Ninja V in 4k with HDMI output from the camera.

Optical Performance: 

The lens has optical limitations, but I was able to get a lot of nice photos from my outing with both cameras. I produced a second video that focuses on the photography outing with this lens. It's a good way to see more samples than what I could realistically show in the main video.

Many of the images here have a full view and 100% crop so that details can be seen where I think the focal point was. 

 

A close up crop of the center of the image.

You will likely notice vignetting and soft corners as well as lowering of contrast depending on how light hits the lens. Since the aperture is fixed, you can’t improve those properties. Though, a fun experiment in the future might be using something like gaffer tape to create smaller apertures. That might not work considering how the lens focuses, but could be fun to try out.

 

A photo focused further out where you can see a crop of the left side.

Focus breathing is pretty extreme on this lens. Not an issue with photography, but definitely a consideration in video mode. Like I said, I did look at a few videos from other YouTube channels after I had released my main video. It looks like more recent Sony cameras work a lot better in AF-C video mode. 

Take note of the bag on the left and hat on the right between the two. A lot more is visible as focus racks back and forth while the lens is trying to gain focus on the far left near the bag.

In bright side-lit scenes you’ll lose contrast and there’s no lens hood or filter thread to help with that. It's a trade off for having such a thin profile lens. 

 

This close up crop shows what happens optically when light hits the lens at certain angles.

What flare can look like. It could be used creatively if you are into that.

Diffraction spikes (sunstars) are present, but not super well defined considering the aperture is fixed to f/4.5. It can be pretty unique looking! 

What the diffraction spikes look like when conditions are ideal.

That said, the background image quality can look nice, especially on full-frame. You can get smooth and interesting backgrounds at f/4.5. For landscapes, it’s workable, but you’ll deal with the aperture limitation and vignetting. I did manage decent landscape style shots but it isn't a lens designed for that purpose. 

Smooth backgrounds are possible considering the f/4.5 aperture limitation.

 

The Viltrox AF FE 28mm f/4.5 VCM ASPH ED Lens box.

This lens feels like a good example of what is possible with the short registration distance of mirrorless cameras. You've got the small front element of the lens with a large back piece of glass. I have seen quite a few native mirrorless lenses from camera companies following that design, but this feels like an extreme example in line with a much more expensive lens like the Nikon Z 26mm f/2.8 at 1/5th of the MSRP. The Viltrox looks thinner in use and has a built-in lens cover. The Nikon likely has higher image quality, faster focusing, and a larger maximum aperture. 

I'd personally like to see a future lens combining the two designs. A lens still as thin as possible but offering a filter thread, higher magnification, a maximum aperture of f/3.2 or f/2.8, consistent optical performance, and a quick and accurate focusing motor.

It seems like Viltrox could be on the path now to develop many very interesting compact lens designs for mirrorless cameras!

 

Check out the Viltrox AF 28mm f/4.5 FE Lens for Sony E-mount:  

• B&H: https://bhpho.to/40cwMTy 
• Amazon: https://amzn.to/4kz4qdt 
• ebay: https://ebay.us/MKVVgC 

As an affiliate of these shops, I earn from qualifying purchases! It's more about time from the click rather than what you buy. Usually anything within 24 hours of the visit.