The Zeiss Loxia 35mm f/2 Biogon T* is a manual focus, wide angle lens designed for Sony E Mount. Based on the classic Biogon design, this lens provides exceptional sharpness in a light-weight form factor.

Optical Design

The Loxia 35mm uses a traditional Biogon design with 9 elements in 6 groups. This was an interesting choice by Zeiss. Biogon is an excellent wide-angle design that works with a tight distance from the lens to the focal plane. Note how the last element is at the very end of the lens. Biogon’s work best for mirrorless or rangefinder formats since it won’t clear the mirror in an SLR camera. Even the classic Hasselblad SWC was a special camera and not a system lens and that was why.

Biogons have a somewhat symmetrical layout of elements. Its an older design, but has a beautiful look to it – it definitely has the 3D quality that most people desire.

Zeiss Loxia 35mm Lens Design

MTF Charts

Zeiss take their MTF readings from actual production lenses. Their quality control is always outstanding. The top MTF is a reading at f/2.0, the bottom at f/5.6. You can see clearly how the lens gets much sharper by stopping down. The lenses in this series work great in low light, but their best performance comes when you stop them down. Micro-contrast cleans up beautifully at f/5.6 – that’s the sweet spot where this lens starts to sing.

At f/2.0 this lens does some strange things. As you can see from the top MTF chart, contrast does a lot of dipping across the frame. There’s almost a pictorialist quality to the images. This won’t be to every photographers taste, but I personally like that there’s one more dimension. By f/4 all the blemishes are sorted out but for photographers who shoot in low light and want an interesting look – you’ll get it at f/2.0.

Zeiss Loxia 35mm MTF

Ergonomics

Loxia lenses are some of the nicest build quality you will find from any company. They’re manual focus, but feature an all metal construction with engraved markings. They are beautiful and feel solid. There is an adjustment screw on the bayonet surface that you can turn with the included tool to “de-click” the lens. This makes the aperture collar glide through all of the f stop settings without click stopping. This is used primarily for video application. Since this is a manual focus lens, its a mechanical focus collar – NOT fly by wire.

Specifications

• 35mm E Mount / Full Frame
• Biogon Optical Design
• 9 elements in 6 groups
• f/2 to f/22 aperture range
• Zeiss T* Anti-reflective coating
• Manual Focus
• Manual Aperture Ring – de-clicking option for video
• Electronic interface – transmits lens data to the camera
• all metal
• Weather Resistant lens mount

Sample Images:

Relative Illuminance

Loxia 35mm Relative Illuminance

The solid line represents the measurement taken at f/2.0, the next line up at f/4.0 and the top at f/5.6. You can see vignetting cleans up quickly as you stop down. Even wide open this can be corrected in post.

Relative Distortion

Loxia 35mm Relative Distortion

The Zeiss Loxia 35mm is one of the cleanest lenses you’re going to find with distortion. Both readings were performed on a Sony A7r. The top graph is with in-camera correction turned on. The bottom shows in-camera correction turned off.

Conclusion

I am a huge fan of Zeiss and their partnership with Sony has produced some brilliant lenses. I think that the idea with this lens was to give photographers a manual focus option similar to what Leica offers: a wider aperture lens for low light situations that stops down for landscapes and other high precision types of work. The Loxia 35mm f/2.0 delivers this. Its a wonderful lens with a classic Zeiss look to it that’s quite versatile. This is an excellent street photography lens that can turn around and shoot sharp landscapes.

My favorite part is we used to have to adapt lenses for this kind of thing. The Loxia 35mm transmits data to the camera so there’s never guessing in post production software. Also since its talking to the camera, you can set this up for zoom magnification when you turn the focus collar. With autofocus as good as it is now, I was initially skeptical of if I’d really like this lens. To my surprise its shockingly easy to use.

Also impressive is how small and portable this lens is. Pair this with a Sony A7r III and you’ve got an incredible rig for landscape shooting that rivals medium format – without having to carry heavy equipment.

Highly recommended.