Minolta MC Rokkor SI 28mm 1:2.5 W – MC II – review

Published by Tony on

Minolta MC Rokkor SI 28mm 1:2.5 W vintage manual lens review (Minolta MC W Rokkor-SI 1:2.5 f=28mm)

  • Official classification: MC
  • Collector’s classification: MC II, Hills &Valleys, Knurled

A very popular lens which is often mentioned in recommendations for someone who is looking for a wide-angle tool.

Minolta MC Rokkor SI 28mm 1:2.5 + Minolta SRT-101

Minolta MC Rokkor SI 28mm 1:2.5 specifications

# in minolta.eazypix.de index 43
Name engraved on lens MC W.ROKKOR-SI
f[mm] 28
A max [1/f] 2,5
A min[1/f] 16
Lens design [el.] 9
Lens design [gr.] 7
Filter thread Ø front(rear)[mm] 55
Lens Shade screw-in
closefocus[m/ft] 0.5/1.5
Dimension Ø x length [mm] 64×61
Weight[g] 340
Year 1970
Style MC II
Code No. (ROKKOR-X) or Order No. 607-018

More data

Floating elements NO
Aperture blades number 6
Confidence in the test results of reviewed copies Enough high
Reviewed Lens SN: 1561256

Historical notes

The lens has three reincarnations – MC I, MC II, and MC III (by popular collectors classification). This revied “Hills & Valleys” or “Knurled” design is MC II – the second generation that was born in 1970. All released lenses with parameters 28mm F2.5 by Minolta are radioactive. If my information is correct, the Minolta produced for 35mm cameras only two lens models which contain active elements in the glass – this 28/2.5 and 58/1.2 (reviewed already in non-radioactive version).

The 28/2.5 hasn’t non-radioactive versions but from my point of view the level of activity is low and if to follow simple rules (like not to eat yellow snow… the yellow glass I mean. But yellow snow also in this list…) everything will be fine. I recommend to google more about radioactivity if you are worried. It seems to me that this trait adds a few scores for the popularity of this lens – it makes it a little unique and dangerous, so, only real rebels and cool guys can use it.

About yellowing of tested copy

The reviewed copy has the easily visible yellow-tint on the back lens – it’s a result of radioactive decay. The color can be easily fixed with an ultraviolet lamp (or sun-bath) but I prefer to leave it because two reasons, firstly I wanted to check how easy it can be fixed with auto-WB in digital editors, secondly the keeping this tint untouchable may turn the lens into good example which demonstrates the radioactive effect on glass if such example will be needed in future, for today this is only one radioactive lens which is available for me.

Minolta MC Rokkor SI 28mm 1:2.5 lens exterior

Minolta MC Rokkor SI 28mm 1:2.5 mounted on camera Minolta SR-T101

Minolta MC Rokkor SI 28mm 1:2.5 sharpness

Сlose-distance resolution test, minimal distance

Testing methods description

  • Target: 10-15 cm picture, printed on glossy photo paper
  • Distance: 1.7m
  • Camera: Sony A7II (24mpx, full-frame, tripod, remote control). M-mode, ISO fixed, WB fixed, SteadyShot – OFF.
  • The test was repeated for every F-stop on every focus position with manual focus adjustment for each shot. That is to avoid the effect of field curvature.
  • RAW processing: Capture One, default settings. All quality settings – 100%. Crops – 300×200 px

Original target image (printed in horizontal orientation on 10cm X 15cm glossy photo paper)

Scene preview

Test results

Long-distance resolution test

Testing methods description

  • Target: cityscape
  • Distance: > 200 meters to center focus point
  • Camera: Sony A7II (24mpx, full-frame, tripod, remote control). M-mode, ISO fixed, WB fixed, SteadyShot – OFF. The focus point is on the center only.
  • RAW processing: Capture One, default settings. All quality settings – 100%. Crops – 300×200 px

Scene preview

Test results

Minolta MC Rokkor SI 28mm 1:2.5 aberrations


Geometric distortion

Coma aberrations

Chromatic aberrations

Long-distance bokeh


Test conditions: the lens was focused on 0.5m, buildings are on “infinity”-distance


Test conditions: lens was focused on 1m

Light bubbles bokeh – infinity

Test #1

The lens is on the minimal focusing distance 0.5m, lights are on infinity (cityscape)

Test #2

Test conditions: lens was focused on 1m

Minolta MC Rokkor SI 28mm 1:2.5 final conclusion

Instead of other lenses from the era of “full metal jackets” this lens, not just a simple “steel&glass” but “steel&glass&radioactivity” so it is a treasure for anti-plastic rebels and a nice training tool for the preppers. Of course, it’s not the only advantage.

Seriously, it has low aberrations and nicely fixed geometric distortion. I’m not a connoisseur of bokeh from wide-angle lenses but test samples demonstrate that this lens has a pleasant rendering that may be successfully used for a herbs/flower photography or subject photography, etc.

About the sharpness: the lens is really sharpened and provides enough good resolution over the frame from F5.6 (F8.0 is better of course) – an amazing result for wide lenses. No doubts that it is the best 28 lens from the “steel&glass” series. I can’t say that this is a gem, but it stays on position right after fantastic New-MD 28mm F2.

What about radioactivity – it seems to me as a disadvantage, not because of influence for health – just follow simple rules and everything will be fine, but because of the fact of the existence of these rules (and of course not because of yellow tint which can be easily fixed).

The lens can be recommended by it’s IQ, but what about the disadvantages – it’s a personal choice of a photographer.



Zeek · 2022-04-01 at 18:33

The MCIII (or MC-X in the US) has the rubber grip and it’s less common, it’s official measurements are; 65.8mm x 61.5mm and 350g. Your version tested here is 64mm x 61mm and 340g even though it has a larger all metal focus control it weighs less ? The MCIII/X version is much larger appearing than your version tested here, and much longer than a MDII 24 2.8 or MC 50 1.4 by nearly double. It is the physically largest 28mm (2.8) lens I know of without going ultra fast. I have also noticed that the yellowing effect is far less intense and only slight often in other samples, there’s only a 1969 to 1973 separation in productions so I don’t believe age is a factor. I have had MCII samples that were almost opaque and amber. The benefit of the tint is huge for b&w in both landscapes and for dramatic skins tones. My sample out resolves my MDII 24 2.8 in intense pixel peeping only. On M4/3’s it rivals the Lumix Leica 25 1.4 except in speed obviously, that’s a blow out. Thank You for your contributions, btw.

Dk · 2023-07-18 at 12:46

I’m curious can radiation damage the digital camera sensor?

Leave a Reply

Avatar placeholder

Your email address will not be published. Required fields are marked *