* Item pictured for illustrative purposes only, actual item not pictured. See ‘Notes’ next to grade for included items.
Nikon 45mm f/2.8 GN Auto NIKKOR Non AI Manual Focus Lens {52}
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All rental gear is between Excellent and Like New Minus condition
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Standard accessories included
Nikon 45mm f/2.8 GN Auto NIKKOR: flash metering built into the glass.
The GN Auto NIKKOR 45mm f/2.8 is a specialized piece of Nikon F-mount history, designed around a specific problem: getting correct flash exposure without a dedicated TTL meter. The Guide Number Auto coupling links aperture to focus distance, so as you focus on a subject, the lens sets the appropriate aperture for a given flash guide number. For photographers who understood the system, it removed a layer of manual calculation from flash shooting.
The lens uses a Non-AI mount, meaning it predates Nikon's Automatic Indexing coupling introduced in the mid-1970s. It will mount on modern Nikon F-mount bodies, but metering compatibility depends on the body. On film-era Nikon bodies designed for Non-AI glass, this lens works as intended. The 52mm filter thread is a Nikon staple, so existing filter sets carry over without adapters.
At f/2.8 on a 45mm focal length, this sits in near-normal territory, slightly tighter than a 50mm, with enough working distance to feel natural for close subjects. As a piece of functional photographic history, it rewards shooters who want to understand flash exposure at a mechanical level.
Who It's For
Film photographers shooting with vintage Nikon bodies who want to work with manual flash systems will find the GN Auto coupling genuinely useful than a novelty, the lens does real work once you understand guide number math. Collectors drawn to Nikon's pre-AI era have a strong reason to seek this out, as the GN Auto designation marks a distinct design philosophy. Experimental shooters interested in mechanical exposure control, particularly in a 45mm normal-adjacent focal length, get a lens that imposes discipline on the flash relationship between distance and aperture.
Key Features
- 45mm focal length, near-normal angle of view
- f/2.8 maximum aperture
- GN Auto guide number coupling for flash metering
- Nikon F-mount Non-AI design
- Manual focus operation
- 52mm filter thread
FAQ
- What does GN Auto mean on this lens?
- GN Auto links the lens aperture to focus distance, automatically setting the correct f-stop for a given flash guide number as you focus. It eliminates manual aperture selection for flash exposure once you dial in your flash's guide number.
- Will this lens work on modern Nikon F-mount cameras?
- It will physically mount on modern Nikon F bodies, but metering compatibility depends on the camera. Non-AI mounts work best with film-era Nikon bodies designed for Non-AI glass; modern DSLRs and mirrorless cameras won't recognize the GN Auto coupling.
- What's the practical focal length and angle of view?
- At 45mm, it sits slightly tighter than a standard 50mm - near-normal angle of view with enough working distance for close subjects without extreme magnification.
- Can I use my existing filters on this lens?
- Yes. The 52mm filter thread is standard across decades of Nikon glass, so existing filter sets attach directly without adapters.
- How does the GN Auto system compare to modern TTL flash metering?
- GN Auto is mechanical - no camera electronics involved. You set your flash's guide number, focus on the subject, and the lens automatically sets aperture. Modern TTL meters the actual light reflected from the subject; GN Auto uses distance and a preset guide number. It's simpler but requires understanding your flash's output.
- Is this lens fully manual to operate?
- Yes. Focusing is entirely manual, and the GN Auto aperture coupling responds to your focus distance - no autofocus or motor drive.
| Specification | Value |
|---|---|
| Focal Length | 45mm |
| Max Aperture | f/2.8 |
| Mount | Nikon F (Non-AI) |
This description was generated using AI based on KEH's internal product standards, product expertise, and knowing what customers care about most. While we strive for accuracy, details may vary by individual item.
| Brand Name | Nikon |
|---|---|
| Filter Size | 52mm |
| Focus Type | Manual focus (only) |
| Lens Mount | Nikon F Non-Ai |
| Lens Type | Standard / Normal |
| Max Focal Length | 45mm |
| Min Focal Length | 45mm |
Learn what to expect from each condition, cosmetically. Images are representative of each grade and may not show the exact item you receive. All equipment is guaranteed to work as intended, unless otherwise noted. We also occasionally offer items that fall .
Exceptions
- New
- New in box complete with manufacturer's USA warranty. Not previously owned or used.
- Like New
- Essentially new with no signs of use. “Open box.” In manufacturer's packaging with original accessories and instructions. 180-day warranty.
- As Is
- Non-functional or damaged. Equipment will not work. Usable for parts. Not covered under KEH warranty and non-returnable.
Like New Minus
Like New Minus
Barely used with virtually no traces of wear. Only the closest inspections will reveal slight use. Lens glass could contain light dust or debris. Excellent picture quality. Accessories usually not included, unless noted in listing. 180-day warranty.
Excellent Plus
Excellent Plus
Lightly used with limited signs of wear. Exceptionally nice but may have slight wear on finish visible. Lens glass could contain light dust or debris. Excellent picture quality. Accessories usually not included, unless noted in listing. 180-day warranty.
Excellent
Excellent
Noticeably used with average signs of wear. Shows moderate wear for the age of the item, with the possibility of blemishes and/or minimal dings. Lens glass may have average dust and zoom/focus ring tension may have slight looseness or tightness overall, but will not affect picture quality. Accessories usually not included, unless noted in listing. 180-day warranty.
Bargain
Bargain
Frequently used with above-average wear. May have dents, dings, or finish loss. Lens glass may have small scratches, dust, and blemishes, and zoom/focus ring tension may have moderate looseness or tightness overall, but should not affect picture quality. Accessories usually not included, unless noted in listing. 180-day warranty.
Ugly
Ugly
Heavily used with extensive visible wear. Equipment is rough, with multiple impressions in the finish, excessive finish loss and brassing. Glass will have marks, fungus and/or heavy/cloudy haze which could affect picture quality. Accessories usually not included, unless noted in listing. Not covered under KEH warranty.
