In February 2009 I decided to improve the
range of the telephoto lenses for my Olympus E-510 DSLR. This page documents the first
stages of this search. The next stage is described in a separate page.
Summary
The results of this comparison show that neither my old 300 mm lens and teleconverters nor
the supplementary lens offer any advantages over the standard Olympus telephoto lens. The
supplementary lens, in particular, is a complete waste of time and money: it produces
results that are much worse than when it's not used. The Olympus EC-20 teleconverter works, but it's not clear to me yet that it works well enough to justify its
price. I can get similar results by cropping during postprocessing.
The requirements
The real issue was the bird bath in the garden; we often get various interesting birds in
it, but my longest lens is a Olympus 70-300 mm
f/4-5.6 telephoto. I needed something longer, and to make it worthwhile it should be
at least 800mm. At that length, there are a few options:
A real telephoto lens with autofocus and automatic exposure. There's only one, the
Sigma EX
DG HSM APO 300-800 mm f/5.6 , and B&H offer it for $7,199—way out of my price range.
A cheap telephoto lens with manual focus and manual exposure, such as the Samyang 650-1300 mm
lens I have seen around. Apart from the obvious problems of manual focus on a modern
DSLR, which isn't really designed to help, this thing has no diaphragm, so you can't
even stop down for more depth of field. It's claimed to be “f/8-16”, but
that's dependent only on the focal length. The price is OK, but the reviews I read of
it were horrible.
Use a teleconverter with my existing lens. That sounds like a good idea, but Olympus
teleconverters are very expensive, and the strongest one is only 2x, so I wouldn't get
beyond 600 mm. It would also drop the maximum aperture by 2 stops.
Use a screw-on supplementary lens, which fits on the filter thread of the lens. This
maintains automatic focus and exposure, and doesn't alter the maximum aperture. They're
cheap, but I've read bad reports about them too, though not as bad as the Samyang lens.
Stick to what I have now, using a Hanimex Pentax thread 300 mm f/5.5 lens with 2x and 3x
teleconverters, which even gets me as far as 1800mm f/33. This one has the great
advantage that it costs me nothing, but the disadvantages of alternatives 2 and 3, and
also the disadvantage I've already noted that the photo quality is worse than “digital zoom”, just using the Olympus
lens at 300 mm and cropping.
I decided that the only reasonable alternative at the moment was alternative 4, and found a
suitable-looking lens for $129 on eBay from
onlinedigitalshop. Send
a message stating what I want to use it with, and received a reply telling me it should be
fine, so bought one. I'm still not sure that was the correct thing to do, but we'll see.
It, too, can be returned, limiting my exposure to about $30.
The supplementary lens
The supplementary lens was a disaster! I've never seen anything so bad. I'll go into
better comparisons below, but a friend summed up my first
impressions: “It looks like the photo was taken through the bottom of a coke
bottle”:
The Olympus lens with the EC-20 teleconverter, effective focal lengths 140 to 600 mm.
The Olympus lens with the 3x supplementary lens, effective focal lengths 210 to 900 mm.
The Hanimex lens with a 2x teleconverter, effective focal length 600 mm.
The Hanimex lens with a 3x teleconverter, effective focal length 900 mm.
The Hanimex lens with the 2x and 3x teleconverters, effective focal length 1800 mm.
300 mm
There are a number of different ways to get a focal length of 300 mm. Using the Olympus
zoom by itself should give the best results, but I can also use the Hanimex, the Olympus
with the supplementary tele or the Olympus with the EC-20. Here they are at different
apertures. The combination with the EC-20 doesn't supply f/5.6—the widest aperture is
f/11—so I've put that one last. There are two rows of photos for each aperture:
first, the full frame, and secondly a detail. Note the severe vignetting from the
supplementary lens at all apertures
It's interesting to note the colour difference of the Hanimex. Also, it appears that the
supplementary telephoto doesn't quite deliver on its promise of 3x magnification. But
that's dwarfed by the appalling quality.
600mm
I didn't use the supplementary lens at this focal length; we'll see it again at 900 mm.
Here we have the Hanimex with 2x converter, the Olympus at 300 mm with the EC-20, and the
Olympus at 300 mm cropped to size (“digital zoom”).
Now we're down to the Hanimex and the supplementary lens. This is the one place where the
supplementary lens has an advantage: it's the only combination to offer f/5.6 at this focal
length. But at what a price! Here the Hanimex with 3x teleconverter and the Olympus with
the supplementary lens. The apertures are all over the place here, of course; I should have
taken photos with matching real apertures. Each image is first full frame, then detail.
Somehow this combination of focal length and lens confused the exposure system of the
camera. I took additional photos with corrected exposure at f/22, but not here.
This photo was taken with fully 2 EV less exposure than the camera calculated. I don't
understand this: the photos I took yesterday didn't show this problem.
At this focal length, there's only one contender left: the Hanimex with 2x and 3x
teleconverters. The exposure seems to be a little on the low side, but could easily be
corrected.
Of course, longer lenses aren't the only way to get bigger pictures; digital processing,
either in the camera (“digital zoom”) or afterwards, can achieve the same
effect. The picture quality suffers, but so it does with these el-cheapo lenses. Here's an
example of the detail at “900 mm”, taken from left to right with the Olympus
with the supplementary lens, with the Hanimex and 3x teleconverter, with the Olympus lens by
itself at 300 mm and enlarged during postprocessing, and with the Olympus lens and the EC-20
and enlarged during postprocessing. It's clear that this shows a continuous improvement.
In other words, the supplementary lens is worse than useless, since the results are worse
than if I don't use it. The EC-20, on the other hand, shows some advantages.
The following photos compare to full frames at an effective focal length of about 4500 mm
(9000 mm equivalent on a 35 mm camera). Clearly even the good ones are a little fuzzy.
