Pentax Auto 110 Lenses on Full Frame: 18mm, 24mm & 50mm Tested

The quick verdict

I adapted the tiny Pentax Auto 110 18mm, 24mm, and 50mm lenses to a Sony a7S III. The 50mm came closest to a usable full frame image. The shorter lenses gave me much stronger edge distortion, blur, and incomplete coverage.

This was a digital experiment with lenses designed for 110 film. I liked seeing what they would do outside their intended format, but I would choose a normal full frame lens when I needed clean edges.

My Auto 110 to Sony setup

I found a used Auto 110 kit with all three lenses for under $100. That was my particular find, not a price I would expect every buyer to get.

I used a passive Fotasy Pentax Auto 110 to Sony E adapter. Auto 110 is its own lens mount, so a Pentax K adapter is the wrong part. On the Sony, focus was manual and the lenses stayed at f/2.8.

These lenses have no aperture ring or internal iris. The original camera body handled the aperture. A simple passive digital adapter does not give them a normal adjustable diaphragm.

I kept the camera position the same for the comparisons. These results come from the Sony, not from shooting a roll of 110 film.

18mm, 24mm, and 50mm compared

These are observations from my copies and adapter. I would test the actual combination rather than assume every old lens and adapter will behave identically.

The 50mm was the easiest to use

The 50mm gave me the most complete frame. There was still some darkening and softness near the edges, but the center was easier to work with.

If I wanted to try just one lens from this group on full frame, this would be my first choice. I would keep the main subject away from the corners and decide whether I liked the falloff before buying a whole kit.

The 18mm and 24mm were much stranger

The 24mm became very distorted and soft away from the center. The 18mm showed the limits of its image circle even more clearly.

The 18mm could suggest a fisheye look in the way the restricted image filled the frame, but it is not actually a fisheye lens. Using it far beyond the format it was designed to cover created the unusual result.

Cropping can hide the worst edges or the visible image circle. It also narrows the view and throws away part of the file, so I would judge the cropped result at the size I actually planned to use.

What to inspect in an old kit

• The exact Auto 110 mount and a correctly fitting Sony E adapter.
• Smooth focus movement, secure mounting, and clean glass.
• Haze, fungus, scratches, or separation that could affect the image.
• Loose material in an old pouch before placing clean lenses inside.

My old pouch was shedding material. I would clean or replace that before using it for storage. A small lens is still worth protecting from debris.

You do not need the original film body or any film to use these lenses with a digital adapter. Buy a complete kit only if you want the camera too or the package makes sense at its asking price.

If you also want to try 110 film

The Auto 110 body uses 110 film cartridges. Check the body, film availability, processing, and scanning costs before treating a cheap kit as a complete film setup.

Check Lomography’s current 110 film selection. This digital lens test does not establish how my kit performs on film.

My verdict

The 50mm was my pick for a full frame experiment. The 18mm and 24mm were better suited to pictures where the distorted edges or restricted coverage were part of the idea. I would start with one inexpensive clean lens and the correct adapter rather than buy the set expecting conventional full frame performance.