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Language Teaching in Japan
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The KM / Sony 18-70mm kit lens |
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This is a little look at
analysing a lens, and getting to know it better. If you are considering
purchasing this lens, then the following should give you a good idea of
what to look for in lenses, even for Canon, Nikon, and other brands.
This is a user review, that is, it's not an objective review, but a very
subjective (user's) review. |
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Background
The Minolta camera company began in 1928,
and has been producing both lenses and cameras since that time. In 1985,
Minolta changed their system to the Auto-Focus (AF) system, which
included evolving their existing lenses. Today, Sony continues the AF
system as the 'Alpha' system, whilst carrying on the tradition of
improving on top quality lenses with successful refinements. This
Minolta 50mm f1.4 lens is from that heritage, designed many years
before, continuously refined, and this was made perhaps in the 1980's.
In 2003 Minolta merged with Konica to form Konica Minolta [1], hence the
"KM" in the brand title. Then KM backed out of the SLR business in 2006,
leaving the camera division in the hands of Sony [1].
This is the fabled "kit lens" that came
supplied with the Konica Minolta Alpha Sweet / Dynax 5 / Maxxum 5, then
numerous consumer models under the Sony label including the A100, A200,
and the early A300 series. The Sony version is mechanically and
optically exactly the same, though cosmetically a little different.
Without a doubt, this would have to be the worst lens produced by KM /
Sony for the Auto Focus / Alpha mount. However, because it is so cheap
to produce, and covers the general needs of consumers it seems to have
become quite popular. To me, it's nothing more than a yogurt container
with glass attached.
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| The
Konica Minolta / Sony 18-70mm kit lens |
For
more talk on these lenses |
First test shots (all handheld)
| Picture 1. The
World Cosplay Summit 2008, in Nagoya, Japan. In the field, at night
and with a flash it performs fine, no focusing problems and no
apparent distortion. KM 5d,
F5.6, 1/125, iso800, at 50mm. |
1.
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| Picture 2,
Yunoyama. It's a very general purpose lens, and it's
lightweight, making it perfect for hiking and mountain climbing (and
other high risk of breakage activities). KM 5d,
F9, 1/125, iso100; at 18mm, with Cokin P160 linear polariser |
2.
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| Picture 3
It claims to be a macro lens, but it's
not. A real macro lens is a little bit different, but instead, this
allows you to focus from as little as 38cm [2], making it
more of a 'close-up' lens. KM 5d, F10,
1/100, iso200 |
3.
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| Picture 4
Despite it being as good as a yogurt container with glass
attached, in studio situations it can perform well, except in Manual
Focus, where the focus ring is so loose that it's almost impossible
to get a good fix. Incidentally, this image has sold well. KM 5d,
F11, 1/125, iso100; 800watt flash |
4.
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| Picture 5
It's perfect for messy, clumsy, sticky-fingered photographers... and
their children. It can do all right for portraits, but it tends to
be soft for my liking. Portraiture is definitely not what it's
designed for. KM 5d,
F11, 1/125, iso100; 18-70mm lens.
800watt flash |
5.
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| Picture 6
This sample is not from the 18-70mm kit
lens, but from the 75-300mm kit lens. The 18-70mm does suffer from
chromatic aberrations, just as its longer stable mate does. |
6.
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| Picture 7
It tends to suffer from barrel
distortion [3], where in similar pictures you'd see power lines and
smoke stacks leaning in towards the middle of the picture.
KM5d, F22, 1/80, iso100; at 60mm; Cokin
P124 tobacco graduated filter, and tripod used |
7.
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| Picture 8
This image used the Cokin P124 tobacco graduated filter, which needs
to be kept upright to maintain the a level tobacco line (the bottom
is clear and gradually changes to tobacco colour to the top).
However, the front element rotates as it focuses, so you need to
readjust the filters, which becomes difficult
when in manual mode. KM 5d, F8,
1/25, iso100; at 45mm. |
8.
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| Picture 9.
The camera allows you to focus from a minimum distace of 38cm [2],
and when coupled with the Cokin P103 (+3) magnifier you can get all
right macro shots. Though, both of these are soft, but suited
for this particular instance. KM 5d,
F6.3, 1/160, iso250; at 60mm. |
9.
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| Picture 10.
In the Christmas-Tree Bokeh Test (a test I invented), not yet done,
but coming. I can tell you now, it won't be good, so don't bother
waiting. |
10. |
Comments
This lens came with my purchase of the KM
5d, replacing the 35-80mm lens I had previously, and is now on long-term
permanent loan to a friend. I should have bought the 5d 'body-only'. The
lens is a "DT" by classification, which means the image circle it makes
is too small for film, but is fine for the APS-C digital sensor. I wish
I had not got this lens, and kept my 35-80mm, as that was full frame,
and so any distortion it had won't appear on the sensor. However, having
18mm (27mm on APS-C 35mm film equivalent) can be useful. It's really
light weight, ultra cheap, and so it has it's uses.
Specifications:
Its minimum focusing distance is 38cm [2], and it's marketed as a macro
lens, though it's not a one (see here for more
information on macros).
Made for film:
Not. It's DT, so only for APS-C format digital and APS-C SLR film
cameras (I don't think Minolta made APS-C format SLR film cameras, but
others have).
Focusing: This is also considered as
it can be taken as a sign of build quality. The manual focusing ring is
fairly loose, making it aggravating when trying to do very fine manual
focusing. Also, in auto focus mode, it can be moderate in speed.
Money Talks:
For a cheap, disposable, light weight lens for a holiday, for testing
experimental photographic-diving equipment, you can't go past this.
Flexibility:
18mm wide-angle ability is nice, especially for the family user. Being
ultra cheap makes it great for experimenting rock-climbing photography;
being lightweight is great for hiking.
Filters:
The 55mm front screw mount element does rotate, making it a nuisance
with graduated filters and polarisers (see Picture 8, above).
Quality Controls:
I think they forgot to do this when manufacturing. Well, in all honesty,
I think they made them pretty consistently, and I've never heard of one
of these failing. Unfortunately, I'm sure mine will live on for a very
long time. The outer case is made of hard plastic, adding to it's light
weigthtness, and it just may be durable.
Final Rating:
Well, what does a number mean, anyway? I've learnt it's limitations, its
weaknesses and strengths, and feel more confident in knowing when to use
this lens, and when not. It can be really soft, and especially
noticeable on portraits, so it's limited there. It doesn't like direct
sun, so cloudy days and in-studio use is fine for it. Avoid using it at
the 18mm end, as it suffers badly from barrel distortion [3], and it's
soft at 70mm. This lens was perhaps made for the a 6mp KM 5d and 7d, but
not for higher resolutions, as its flaws tends to be even more
pronounced. This lens has now been replaced by the SAL18-55mm SAM on the
A230, A330, and A380 series, so hopefully the 18-55 is a better product.
References
[1] Minolta, Wikipedia. Accessed 25 Sept
2009.
http://en.wikipedia.org/wiki/Minolta
[2] Mhohner.de. Accessed 25 Sept 2009.
http://mhohner.de/sony-minolta/onelens/afdt18-70f35d
[3] PhotoZone.de. Accessed 25 Sept 2009.
http://www.photozone.de/sony-alpha-aps-c-lens-tests/140-sony-18-70mm-f35-56-dt-review--lab-test-report
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