A-mount, bright wide-angle lens MINOLTA AF 28mm F2

1．Overview

The MINOLTA AF 28mm F2 is an autofocus prime lens released by Minolta in 1987.

It is a simple lens with only one control on the lens barrel: the focus ring.

There is a new model of this lens called (New) released around 1998, and an older model from 1987. The only difference between the two is the focus ring design, but the internal lens structure is the same.

It does not feature the focus hold button that is featured on some (New) lenses.

It is possible that the lens coating on the newer model is better, but there are no clear sources for this.

The main specifications of this lens are as follows,with details listed in the specifications table.

• Lens Construction: 9 Elements in 9 Groups
• Minimum Focus Distance: 0.3m
• Filter Diameter: 55mm
• Dedicated Bayonet-Type Flower-Shaped Hood
• Distance Encoder Not Compatible

This lens is a Sony A (α) mount lens, so the aperture is set on the camera. The lens has a minimum focusing distance of 0.3m, which is not particularly distinctive for a wide-angle lens.

It does not have a lens motor, and the autofocus system relies on the camera’s driving force.

As it does not use the SSM (Ultrasonic Motor) / SAM (Smooth AF Motor) motors that are mounted on the lens itself, as used in later Minolta and some Sony lenses, there may be limitations when using it with a Sony α mirrorless camera via a genuine Sony mount adapter.

The restrictions are summarized in the “Specifications, Considerations, etc.” section.

2．Usability

The MINOLTA AF 28mm f/2 is a Sony A (α) mount lens. When used with the α900, a 35mm full-frame sensor camera, it maintains a focal length of 35mm. However, when used with an APS-C sensor camera, it becomes a semi-standard lens equivalent to 42mm, multiplied by the sensor size conversion factor of 1.5.

Looking at the results with a 35mm full-frame sensor, the first sample image is taken at full aperture, with the focal plane positioned at the eye, but the ear is already blurred, confirming the thinness of the focal plane that is not typical of lenses in the f/2.8 class. The corners at full aperture are softer than with the AF 35mm f/2, but as can be seen in the last two sample images, improvement is seen when stopped down to around f/8.

Since sharpness is higher in the center near the maximum aperture than in the periphery, cropping the periphery on an APS-C sensor likely results in a uniform, well-defined image at all apertures. However, the distinct characteristics of the image at full aperture are diminished.

Like Minolta autofocus lenses of the same period, flare and ghosting can occur in backlit situations, but this can be addressed by attaching a hood or cutting out flare.

When using it with the Sony α900 and α700 A-mount digital cameras, I was satisfied with the focusing speed. Furthermore, even in close-up photography, where precision is crucial, the autofocus can accurately focus without hesitation, as long as the subject is reasonably clear. For subjects that autofocus is not good at, the photographer will need to use their own ingenuity, such as changing the shooting mode to manual focus and adjusting the focus position. This lens does not have a built-in distance encoder (D), so direct manual focus is not possible.

Perhaps because of the limited production of the (New) type, used items often fetch above list price when they appear on the market. I sold it when it was at its lowest price, and it’s one of those lenses I wish I had kept.

3．Summary

The MINOLTA AF 28mm F2 is a wide-angle lens that’s one stop brighter than other lenses with a focal length of 28mm.

Like Minolta lenses of the same era, rendering at wide apertures is a little soft, so you’ll need to select the appropriate aperture depending on the scene.

Also, the focal plane at F2 is narrower than you might expect, so if you rely on autofocus, the focus position will be slightly off. Therefore, if you have the time, it’s better to use focus bracketing, which involves taking several shots with different focuses, to reduce regrets when you see the results.

Specifications, considerations, etc.

MINOLTA, the predecessor to Sony cameras, was a camera manufacturer with a full line of lenses, but this bright wide-angle AF 28mm F2 was only released under the Minolta brand; no Sony version was ever released.

The first release was the α-mount version in 1987, and in 1998 (or 1999) it was upgraded to the (New) model with a revised exterior, but it was not updated to the (D) model with a distance encoder for use with flash control.

Also, this lens did not feature the focus hold button found on some (New) lenses, such as the AF 35mm F1.4 (New). Even though it was an F2 lens, the depth of field at full aperture was shallow, so it would have been nice to have a function added, but it is believed that this was because the lens barrel was small and there was no room to add a physical button.

Evolution of the MINOLTA AF 28mm F2

• Y1987 Minolta AF 28mm F/2
• Y1998 Minolta AF 28mm F/2 RS

The A-mount was the world’s first commercially available autofocus interchangeable lens camera mount, but early A-mounts used a motor in the camera body to drive the lens, and while the aperture was controlled from the camera, the actual aperture mechanism was operated mechanically with a lever.

Because the flange focal distance between other companies’ SLR cameras was only a few millimeters shorter, it was difficult to incorporate a mechanism to drive the aperture, even if the focus mechanism could be moved. As a result, no mount adapters were made to allow A-mount lenses to be used with other companies’ SLR cameras.

With the advent of mirrorless cameras, the difference in flange focal distance between SLR cameras was reduced to around 20 mm, and Sony released a mount adapter to allow genuine A-mount lenses to be used with E-mount cameras. There are five types of mount adapters, the features of which are briefly described below.

• LA-EA1: Aperture control + limited autofocus for APS-C sensors
• LA-EA2: Aperture control + autofocus for APS-C sensors (with translucent mirror)
• LA-EA3: Aperture control + limited autofocus for 35mm full-frame sensors
• LA-EA4: Aperture control + autofocus for 35mm full-frame sensors (with translucent mirror)
• LA-EA5: Aperture control + autofocus + camera limit for 35mm full-frame sensors

If you want to use older A (α) mount lenses like the MINOLTA AF 28mm F2 with autofocus, there are two options: for older E-mount cameras, use the LA-EA4, which is equipped with a translucent mirror; for newer cameras like the α7R IV, α7 IV, α1, α6600 and later, use the LA-EA5, which allows you to use autofocus with all A (α) mount lenses.

Sony Lens Compatibility Information

The above is a site where you can select the body and lens you want to use, and then it will show you what restrictions apply to that combination. However, this site doesn’t have a list, making it difficult to understand.
The autofocus notation clearly states if the camera is not compatible, but is silent if it is compatible.

	Image sensor size	AF compatible E-mount camera	Supports image plane phase detection AF with SSM/SAM lenses	Supports focal plane phase detection AF with lenses without a motor (SSM/SAM)
LA-EA1	APS-C	×	×	×
LA-EA2 *	APS-C	△	×	×
LA-EA3	35mm full frame	SSM/SAM lenses only	×	×
LA-EA4 *	35mm full frame	△	×	×
LA-EA5	35mm full frame	SSM/SAM lenses only	α7 II, α7R II, α6300, α6500, α7 III, α7R III, α7R IV, α6100, α6400, α6600, α9, α9 II, α7S III, α7C	α7RⅣ, α7Ⅳ, α1, α6600, and newer cameras

It may be possible to make an A (α) mount adapter for other companies’ mirrorless cameras, but with the aforementioned A (α) mount adapters for the E-mount already available, it is unlikely that any company would be so bold as to make an A (α) mount adapter, which requires complex mechanisms and high development costs, for other companies’ cameras that are unlikely to sell very well.

As an aside, the reason there are so many EF mount adapters for mirrorless cameras from various manufacturers is because the hurdle for product development is low – both aperture and focus are electronically controlled, so as long as there is ROM to convert the control commands, all that’s left to do is match the mount shape to create a mount adapter; and because the EF mount has historically had a large market share, so the market is flooded with used lenses.

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The lens barrel diameter is almost the same as the slightly slower AF 28mm f/2.8, but its overall length is about 7mm longer, but in actual handling there is almost no difference. If you prefer a slightly faster lens, the AF 28mm f/2 is worth choosing.

The AF 28mm f/2 has a more luxurious lens construction, with nine elements in nine groups, compared to the AF 28mm f/2.8’s five elements in five groups. However, it is about 100g heavier. The AF 28mm f/2 also has nine aperture blades, two more than the AF 28mm f/2.8’s seven, resulting in a more circular aperture shape when stopped down. This should make a difference when photographing night scenes.

The used price of the AF 28mm f/2 is higher, so if you can afford the price, it is a lens worth trying.

lens name	AF 28mm F2	AF 28mm F2.8
Focal length	28	28
35mm equivalent focal length (mm)	42	42
Max aperture	2	2.8
Min aperture	22	22
Leaf blade	9	7
Lens Construction	9 elements in 9 groups	5 elements in 5 groups
Min distance(m)	0.3	0.3
Lens length(mm)	49.5	42.5
Max diameter(mm)	66.5	65.5
Filter Size(mm)	55	49
Weight(g)(lens only)	285	185
Lens hood	Bayonet type petal	–
Lens mount	A-mount	A-mount
Release date	1998(New) 1987(Old)	2006(SONY) 1985(MINOLTA)

Reference links

• SONY lens official page
• Sony announces release dates for α lenses and accessories・Degi-came watch
• Y1987 Minolta AF 28mm F/2
• Y1998 Minolta AF 28mm F/2 RS

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Affiliate links

• SONY LA-EA*・Ads by Amazon
• SONY LA-EA5・Ads by Amazon
• SONY α900(A900)・Ads by Amazon
• SONY α900(A900)・Ads by Rakuten

Update history

• 2026.1.31