On 17 February 2009 I investigated a supplementary telephoto
lens for my Olympus ZUIKO DIGITAL ED
70-300mm F4.0-5.6 telephoto lens. On eBay I found a vendor offering a “3x Telephoto Lens for Olympus EVOLT E510 E410 E520”. I've heard
some bad things about supplementary lenses, but the feedback he had for these lenses seemed
uniformly good, so I sent a message just to be on the safe side, and received confirmation
that there should be no problem in conjunction with this lens. So I ordered one.
It arrived a week later. What's the name? It has the
text “Digital Optic” written on it, but who knows if there's a company of that
name?
What a catastrophe! Beyond the discrepancy between the claims and the real quality, there's
no reason to believe that there's anything wrong with this specific item. But it is so bad
that it's worse than useless.
The problems include, roughly from the worst to the least bad:
It's possible that the extreme problems come from the use of this specific lens, and that
things aren't quite as bad with a “standard” lens. But my brief tests with a
Pentax Z-1 and the standard 28-80 zoom lens didn't confirm that. I didn't have a film for
the Pentax, and I didn't want to waste one on this lens, but the viewfinder image looked bad
enough. The vignetting was unacceptable at settings below about 70 mm, and above that the
image in the viewfinder still looked washed-out and unsharp.
The vendor knows this, but doesn't advertise it. In the ensuing email exchange, he wrote:
5. Do not use the camera wide angle mode while telephoto lens is on camera
6. This will cause black borders and tunnel effect around lens
I've done a more detailed
comparison with other ways of extending the telephoto range; they show in particular
that simply magnifying images taken with just the base lens gives results that are much
better than with the supplementary lens. So the whole thing is a waste of time.
Is this a general condemnation of supplementary lenses? No. I think that this particular
lens was designed for video cameras, and I suspect that even there it's not very good. I
have a couple of similar wide-angle lenses that I bought years ago. They don't fit on the
standard lens on my Olympus, but I was able to fit one of them to the Pentax, and the
results looked markedly better. But of course I don't want a wide-angle lens.
Also, despite my “experience” with the Pentax, it's possible that the lens
performs better with a standard lens than with my Olympus telephoto. It's difficult to
understand why so many people seem to be satisfied with it.
Also, Andrzej Wrotniak has done a
similar comparison using
a Sigma DC 55-200 mm lens and a TCON-17
supplementary telephoto and had acceptable results. This was only a 1.7x
magnification, though. So maybe it's worth trying a different brand; but I'll only do that
if it's a question of payment on satisfaction.
