Review: Minolta AF 300mm f/2.8 Apo G (D) SSM

1. Introduction

With telephoto lenses, depth of field is narrow, the long focal lengths make hand-holding tricky, and you're often shooting subjects that don't stand still. This means that fast and precise focusing is critical, bad bokeh has a really unpleasant effect on most pictures, and you'll be shooting your lens wide-open with Anti-Shake turned on most of the time to minimize camera shake. So ideally you want Anti-Shake, fast and accurate focusing, good bokeh and good optical performance at the largest aperture. So lets see how the new Minolta AF 300mm f/2.8 Apo G (D) SSM lens fits this description.

The AF 300mm f2.8 Apo G (D) SSM lens, together with the AF 70-200mm f/2.8 Apo G (D) SSM lens, are the first Minolta lenses to use a supersonic wave motor for focusing. This is equivalent to the Canon USM and the Nikon Silent Wave motor. This AF motor gives a much more quite and smooth AF operation. More on that later. The lens is also part of the Minolta AF G – Series that only uses Minolta's finest optical glass.

When I was heading to India in February 2005 I bought a Minolta 70-200 f/2.8 Apo G (D) SSM lens for the trip. I liked the SSM focusing so much that when I got a really good offer on the 300mm f/2.8 Apo G (D) SSM lens I could not turn it down and bought it to replace my older Minolta 300mm f/2.8 Apo G lens. In this test I compare the newer SSM lens with the older G lens to see if I made the right choice. The lenses are tested on the Minolta Dynax 7D digital SLR. A summary of my thoughts on the lens follows. Remember, this is a subjective review and your opinions might be different. This review is based on my experience with one lens only and sample variations might occur. Anyway I hope you find it useful.

2. SSM Focusing

Minolta’s new SSM lenses employ new supersonic-wave motor technology for quiet, smooth AF operation. Note that the SSM lenses not will autofocus with camera models introduced before the Minolta Dynax/Maxxum 7. The only exception is the Dynax/Maxxum 9 which can be upgraded to take SSM lenses. When you purchase a new SSM lens, Minolta will upgrade one Dynax/Maxxum 9 for free. 

The lens can be used in manual focus on all Minolta cameras.

3. Teleconverters

The SSM lenses will only autofocus when coupled with the new Minolta AF 1.4x Tele Converter Apo (D) and Minolta AF 2.0x Tele Converter Apo (D). These converters are also compatible with all other Minolta lenses. The only difference between these converters and the Tele Converter II Apo's are that the new ones have eight lens contacts versus the older ones five.

4. Lens data

  • Focal Length: 300mm
  • Filter diameter: 42mm drop-in
  • Hood Mount: Slip-on cylindrical hood with locking screw
  • Dimensions: 122mm x 242.5mm (diameter x length)
  • Weight: 2310g (without the 170g tripod mount)
  • Aperture:
    • Largest: f/2.8
    • Smallest: f/32
    • Diaphragm Blades: 9 blade circular aperture.
  • Focusing:
    • Method: Supersonic wave motor, internal focusing, non rotating front element.
    • Minimum distance: 2.0m
    • Maximum magnification: 0.18X
    • Four focus hold buttons
    • Variable focus-range limiter
    • Prefocus function
    • AF/MF switch
    • Two Direct Manual Focus (DMF) modes
  • Optics:
    • Construction:  13 elements (Includes 3 AD glass elements)
                             12 groups
    • Angle of view: 8° 10' 
  • Standard accessories:
    • Lens hood
    • Front cap
    • Rear cap
    • Trunk case
    • Lens strap
    • Tripod-mounting collar
    • 42mm optical element (drop-in filter)
  • Optional accessories:
    • Soft carrying case
    • 42mm drop-in circular polarizing filter
    • Y52, B12, O56, R60, A12, 1B, and ND4X filters
    • AF 1.4x Tele Converter Apo (D)
    • AF 2x Tele Converter Apo (D)
On the left is the 300mm f/2.8 Apo G (D) SSM attached to the Dynax 9 and on the right the older 300mm f/2.8 Apo G (N) attached to the Dynax 700si.

The size of the 300mm f/2.8 Apo G (D) SSM lens is about the same as the older 300mm f/2.8 Apo G (N) lens, however the lens hood is considerable longer as can be seen on the picture.

Length of lens with hood attached:
SSM lens:       37,0 cm
Apo lens :       28,5 cm

Max. diameter of lens with hood attached:
SSM lens:       13,6 cm
Apo lens :       12,8 cm

 

5. Appearance and Handling

This lens was released in March 2003 and is the latest Minolta lens in the G - Series (together with the 70-200mm f/2.8 Apo G (D) SSM). When you first see this lens it gives you an impression of solid quality. The lens is constructed using magnesium alloy internally to hold the optical components, and externally to protect the lens barrel. This keeps the weight of the lens down to a minimum. Even though the weight of the lens, when you include the collar, is the same as the old one it somehow feels lighter. The lens is also much better sealed from sand and dust than the older one. It does not have the recessed focusing ring and the front protective glass element is now part of the lens and not removable. The lens is painted in a finely crinkled white finish. It looks like the same type of paint used on the 28-70mm f/2.8 G lens and looks like it will withstands wear better that the white finish of the older G lenses. The manual focusing collar, placed in the middle of the lens is wide and do not rotate when the lens is autofocusing. The customary golden ring, designating a G construction, is placed in front of the manual-focusing collar. The lens has four focus hold buttons placed right in front of the manual-focusing collar, these are evenly spaced at 90° around the barrel. By pushing one of these buttons you can stop the autofocusing. When releasing the button the lens will start focusing again. By altering the custom functions of your camera you can set these buttons to perform different functions like DOF preview. There is also a read-out window for the distance scale, with some pretty useless depth-of-field indications for f/32, placed just behind the focusing ring.

Behind the focusing ring there are a lot of switches which control the auto focus functions. These are the Focus-mode switch, the upper left one, with which you can switch between autofocus or manual focus. The DMF-mode switch, the upper right one, sets the lens in standard Direct Manual Focus (DMF) or full-time DMF. Standard DMF allows you to fine tune the focus after the AF system has locked onto the subject (only in AF-A or AF-S mode). Full-time DMF gives you access to manual focus control at any time by simply turning the focusing ring. The Focus-range limiter, the middle left button, selects the focusing range. You can choose FULL which is from 2.0m to infinity, from 6.4m to infinity and the last choice is a user defined range. The Focus-range setting switch, middle button on the right, sets the user defined range. To set the range first slide the Focus-range setting switch to the SET position. Then focus the lens to the minimum distance of the range and slide the Focus-range setting switch to the NEAR position. Focus the lens on the maximum distance and slide the Focus-range setting switch to the FAR position to complete the operation. The focus range limiter can be used to reduce the auto-focus time and eliminates the possibility of focusing on an object outside the scene. The third row of buttons is used to control the prefocus function. This allows the lens to store a set focus position that can be recalled at any time by simply pressing one of the four focus hold buttons on the lens barrel. To set the object distance slide the Focus-hold/prefocus switch to the PREFOCUS position. Focus the lens at the correct distance and press the Prefocus set button to store the object distance. The last switch all the way at the buttom, is the Audio-signal switch and turns on or off a audio signal that confirms focusing range is customized or the prefocus distance is set or recalled. The good news is that it does not signal when focus is achived.

The switches are easy to reach and change, still they will not accidentily change position as you handle the lens. This was a big problem with the Canon 70-200mm f/2.8 L USM IS lens. Several times when I brought the camera up to take a picture either the AF or the IS was disengaged accidentily. This happened when I held the camera and lens combination around the lens barrel as I sat on top of an elephant moving through the jungle in search for a tiger or when I had the camera wrapped in a towel to keep dust out when moving around with a jeep at full speed. 

All the way at the back of the lens is solidly built tripod mounting collar that rotates 360 degrees and can be locked at any position. It can easily be removed when you are using the lens handheld. It is a good and compact design.

The lens hood is very large compared to the old 300mm f/2.8 Apo G. It is also detachable and can be reverse mounted for transportation and storage. It is made of lightweight carbon fiber and lined with black velvet to reduce flare. While it theoretically gives a better protection against flare due to the deeper hood, it is bigger and more cumbersome to attach than the sliding hood on older lens. And I never had any problems with flare on that lens either.

The lens uses the totally new (at least for Minolta) SSM focusing. It means that the lens uses an internal motor to adjust the lens elements to focus. The design achieves a much quiter and smoother focusing than the in camera motor used on the other Minolta lenses. The biggest difference is that the lens autofocuses without any noise, which is hardly the case with other Minolta lenses. Focus tracking is also much better and the lens does not run all the way out to infinity when it looses focus like the other Minolta lenses have a tendency to do ever so often. I don't think the speed of the motor is much faster. By that I mean the time it takes the lens to focus from one distance to another. I would say it is about the same as the Minolta 200mm f/2.8 Apo G on the Dynax 9 (which is not bad as I find this combination very fast). But the overall feeling of the focusing is much better. Compared to the Canon EOS 5D and the EF 70-200mm f/2.8 L USM IS lens I would say the focusing with the Minolta Dynax 7D is about the same. And that applies to focusing speed, noise and focus tracking. 

The lens is constructed with 13 elements in 12 groups. Of these three are AD-glass (Anomalous dispersion) elements, one is the protective front element (not removable like on the old lens), and one is a clear optical element screwed into the built-in filter holder. The AD glass elements are used to eliminate chromatic abberations and distortion. High-quality multi-coatings increase transmittance and reduce flare to preserve contrast. A circular aperture keeps the defocused image of point light sources outside the depth of field round between f/2.8 and f/5.6. The filter thread is 42mm drop in filters. The lens is pretty heavy at 2310g but that is about the same as equivalent lenses from the competitors. The 2.0m closes focusing distance however is the best in the class.

 

6. Optical Performance

Different wavelengths of light come into focus at different planes. This effect is know as chromatic aberration and can cause a "rainbow" halo around points of light and reduced sharpness. The Anomalous Dispersion (AD) glass, used in four elements of the lens, virtually eliminates the effects of lateral and longitudinal chromatic aberration, providing increased sharpness and extremely accurate colour rendition.

The tables below summarize my findings when shooting a resolution chart with the lens to test its optical quality. The ratings are as follows:

     *      Very poor 
    **     Poor 
   ***    Ok 
  ****   Good 
 *****  Very Good 


300mm f/2.8 Apo G (D) SSM 

f-stop

Sharpness centre

Sharpness corner

Contrast

2.8

*****

*****

*****

4

*****

*****

*****

5.6

*****

*****

*****

8

*****

*****

*****

11

*****

*****

*****

16

*****

*****

*****

22

***

***

****

32

**

**

****

Overall the AF 300mm f/2.8 Apo G (D) SSM lens delivers a very good image quality. Based on optical performance I would rate the apertures as follows; f5.6, f/8 and f/4 with f/2.8, f/11 and f/16 just a tad behind. While f/22 and f/32 should be avoided as optical performance suffers at these apertures. With the reduced image circle of the digital Minolta Dynax/Maxxum 7D are the sharpness at the corners the same as at the centre. This coincides with the official MTF graph released by Minolta and given below.

Compared to the older Minolta 300mm f/2.8 Apo G lens the sharpness is about the same at all apertures except at f/2.8 were it is noticably better. Sharpness at the edges are also a tad better at f/4 to f/16 with the new SSM lens.

Illumination is even across the frame on the reduced image circle of the digital Dynax/Maxxum 7D.

Geometric distortion is none existent.

The graphs below are the Minolta MTF graphs for the lens.

The graph 
The graph shows MTF in percent for the two line frequencies of 10 lp/mm and 30 lp/mm, from the centre of the image (shown at left) all the way to the corner (shown at right). The bold lines represent sagital MTF (lp/mm aligned like the spokes in a wheel). The thin lines represent tangential MTF (lp/mm arranged like the rim of a wheel, at right angles to sagital lines). On the scale at the bottom 0 represents the centre of the image (on axis), 3 represents 3 mm from the centre, and 21 represents 21 mm from the centre, or the very corner of a 35 mm-film image. Separate lines show results at f8 and full aperture. This is Minoltas own MTF graph for this lens.

7. When the image is out of focus

The word Bokeh is of Japanese origin and relates to the fashion in which the out-of-focus areas of the image are rendered. A sharply focused subject set against a pleasingly silky smooth background characterizes a good bokeh. The transition from in-focus to out-of-focus should occur gradually. A large number of aperture blades give a more circular opening when the lens is stopped down, but this in itself is not sufficient to give a good bokeh. Another feature of the lens that affects bokeh is the degree of spherical aberration correction. Spherical aberration is when the rays of light from the middle and from the outside edges of a lens do not focus to exactly the same point.

The lens has a circular aperture that keeps the defocused image of point light sources outside the depth of field round between f/2.8 and f/5.6. See pictures below. This is much better compared with the older 300mm f/2.8 Apo G (N) and is probably one of the reasons the SSM lens has a better bokeh. The round aperture combined with the good spherical aberration correction of the lens gives the 300mm f/2.8 Apo G (D) SSM a very pleasing image rendition. The background blurring attained by the lens is creamy and silky smooth.

f/2.8 f/4 f/5.6 f/8

8. Flare and ghosting

The narrow field of view of a telephoto lens means that you can use deep hoods that very effectively cut out glare and reduce flare. The lens also uses high-quality multi-coatings and internal baffles to increase transmittance and reduce flare to preserve contrast. So far I have not noticed any problems with flare or ghosting when using the 300mm f/2.8 Apo G (D) SSM lens. 

 

9. Summary and Conclusions

This lens has the excellent optics, build quality and excellent autofocus that is to be expected from a top of the line Minolta G lens. It is equal to or even better than the older version on every aspect. The new silent SSM focusing is much faster and better than the former shaft focusing of the earlier version and the close focusing distance and the smooth manual focusing all comes as a bonus. The pre focus function is a very nice feature when waiting for action to happen. Just pre focus the lens to were you think something will happen, store the focusing distance, and you are free to photograph something else until the action starts. Then just hit the focus hold button and you are ready to go. The detachable tripod collar is nice if you use a beanbag for support. Just take off the collar and the lens becomes lighter and more stable on the beanbag. I am really happy with this lens and don't regret replacing the old one. All I can say is that this an exceptionally fine lens.  

Pros 
   o Excellent optical performance
   o Excellent build quality
   o Fast, accurate and silent focusing
   o Very good bokeh 
   o Image stabilizer with the digital Dynax 5D and 7D (built into the camera body)
   o Close focusing distance of 2.0m is the shortest in its class
   o Removable tripod mounting collar

Cons 
   o Too expensive. It sells new for a lot more than the equivalent Nikon and Canon lenses.
   o I liked the retractable hood of the older lens better than the new detachable design that is more combersome, and not so fast to attach.

So it is worth upgrading from the older 300mm f/2.8 Apo G lens the the new 300mm f/2.8 Apo G (D) SSM? You get better optical performance at f/2.8, more silent autofocus, shorter close focusing distance and some other small features but the price you have to pay is high. I did get the lens at a good price, US $ 3100 instead of the usual US $4600 so I am pretty happy with the switch. However I am not sure I would have done it if I had to pay the normal price which for some reason is a lot more than equivalent lenses from the main competitors.

10. Magazine lens tests

  • German magazine Color Foto test results 
    21 out of 30 on sharpness
    29 out of 30 on contrast
    17 out of 20 on centering
    9 out of 10 on distortion
    8 out of 10 on vignetting
    That makes it 84 out of 100 total and that is the best score by a 300mm f/2.8, equal to the Nikon AF-S Nikkor II 300mm f/2.8 D IF-ED and 2 points ahead of the Canon EF 300mm f/2.8 L IS USM
  • French magazine Chasseur d'Images test results on the Dynax/Maxxum 5D
    Vignetting 5/5
    Chromatic abberation 4/5
    Distortion 5/5
    Sharpness 4/5
    Total score 4/5
    A magnificent lens that gives superb results.

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