E-SYSTEM

ZD EC 14

teleconverter lens on test


INTRODUCTION:

Of all my photography, telephoto work probably represents the highest percentage. This likely reflects the area in which I live and undertake the majority of my shots; deep in the Yorkshire Dales. Here in the sweeping majesty of rolling hills and heather clad moors the natural perspective is already that of wide-angle. Putting a wide-angle lens on a camera to capture an existing wide-angle scene can be overkill. As I explained to a friend once "all wide-angle lenses give me is more blue at the top and more green at the bottom" and I can't think of a more pertinent way of putting it. If I lived in a more 'scenically challenged' area I have no doubt my preference would be different. However, I don't, so it follows that a tele-converter, giving additional reach to existing lenses, would be an early addition to my E-System armoury. Having said that I was never greatly enamoured of OM converters, in particular the OM 1.4 times unit which promised much but failed to deliver. With this in mind, It was with some apprehension I ordered the EC14.

FIRST IMPRESSIONS:

About 9 days later my EC14 arrives. Packed very securely in the silver E-System box the EC14 comes with front and back caps and its own little lens pouch made from black leatherette and suede material. I think these new style pouches are simply awful. The old OM system pouches were much superior but they did lack a hard base so, I suppose, (grudgingly) this new design does the job. The EC14 is made from dense machined alloy, quite heavy, well made and beautifully finished, matching the black finish on other ZD lenses. The two outer facing elements of the six that make up the converter are obviously coated - you can easily see the multi (coloured) coating. The element that faces the rear of the attaching lens is masked to the 4/3rds aspect; something I wasn't anticipating. On the body of the converter is placed an independent lens lock/release enabling the user to dismount the attached lens, leaving the converter fitted to the E-1. And of course there are the 9 pass-through pickups for transmission of lens information to the E-1. I begin to see why this piece is so expensive. BUT, how will this converter perform? Let's go see shall we?

TARGET:

Following my example shots with various OMZ's on the E-1 Body (you can see these here), I decided to use the same target in preference to my flat 2D test chart used previously. The procedure is simple. I set the camera on a tripod at 100 foot from the focus point, put it on P, set the mirror up for 3 seconds and use the remote control RM-1. E-1 settings are: ISO = 200; Sharpness -1; Saturation 0; Contrast 0; Colour Space sRGB; all else except mirror OFF. Images are recorded at SHQ and are reproduced here with no post-processing other than saving at 72 dpi to reduce size for web display purposes. If anyone wants full versions for critical analysis please contact me here.

IMPORTANT: While the reduced versions shown in this article serve for illustration, I have had the benefit of examining the full versions in great detail. Be assured that any significant differences between comparable images will be pointed out whether or not such differences are visually voided in the reduction process.

Test conditions today (dull) dictate that in P mode the E-1 will use the lens' maximum aperture throughout, which is what I want.

I take 5 shots with the ZD 50-200mm at 50, 70, 100, 150 and 200mm. I mount the EC14 on the E-1 followed by the 50-200mm and repeat the exercise taking 5 shots at the effective focal lengths of 70, 98, 140, 210 and 280mm. (Remember to double these to 'convert' into 35mm equivalent thinking).

THE RESULTS:

I'm only showing the results from 50mm/70mm (widest FL of the 50-200mm lens) and those at 200/280mm (long end of the 50-200mm lens) for no other reason than I can't think any intermediate settings will be used much when using a EC14.

There was no-one more curious than me to see the results. Having done a series of tests with Telephoto OMZ's on the E-1 body I have an idea of the quality those lenses can produce (or not as the case may be). Just to remind you of the relationship between ZD and OMZ, the unconverted 50-200mm at 200mm is the equivalent FL of the OMZ 200mm f4 or f5 prime, while the converted 50-200mm at 280mm (more difficult to match) is approximately the equivalent of the OMZ 300mm f4.5 prime.

OK, let's take a look at the results;

No 1: ZD 50-200mm at 50mm



This is ZD 50-200mm at 50mm wide-open. Sharpness/contrast/colour excellent.


No 2: ZD 50-200mm with EC14 at 50mm

This is ZD 50-200mm fitted with the converter at minimum focal length. A 20mm change in EFL.


No 3: ZD 50-200mm at 200mm

This is ZD 50-200mm at 200mm wide-open. This lens is so impressive; its native sharpness is really excellent. Contrast and colour are on the nose too.


No 4: ZD 50-200mm with EC14 at 200mm

This is ZD 50-200mm fitted with the converter at maximum focal length. An additional 80mm in EFL but no discernable drop in resolution or reproduction. It is still extremely sharp; you can easily read the 'Nishikoi' brand on the label from 100' : impressive.

In the above image (4) when viewed at 1:1 in PhotoShop it is just possible to read the price (15.25) on the tiny red 22mm x 16mm label attached to the jar. That's pretty good in my book. PS: I must find a more affordable fish food!


Of course you have to bear in mind that you lose a stop or there abouts with the EC14 mounted. When comparing shots 3 & 4 please remember that the result would naturally 'sharpen' as the effective aperture drops from the max f=3.5 in image 3 to f=4.9 in image 4. I believe this is what we are seeing here.

My tests confirm that the accurate light drop in these (poor) conditions, as registered by the exif information, between shots 3 & 4 is 1.4. This is slightly better than the official Olympus literature that indicates the EC14 converts the 50-200mm f=2.8-3.5 to 70-280mm f=4.0-5.0 (a 1.5 loss). I read somewhere, (my memory is terrible), that the easiest conversion is to multiply both focal length and aperture by 1.4. This is very simple and appears to hold good for the Zuiko Digital range of lenses. But from my past experience with analogue converters on film cameras this straightforward conversion was not quite as clear cut. However, my physics leaves much to be desired so I'll leave it to others to do the maths.

It is plain the EC14 is capable of excellent results, but how does the combination of ZD zoom + ZD tele-converter compare to the OM Zuiko prime telephoto's mounted on the E-1?

Let's see shall we?

No 5: ZD 50-200mm at 50mm, no tele-converter



This is ZD 50-200mm at 50mm wide-open. Sharpness/contrast/colour excellent.


No 6: OM Zuiko 50mm 'standard' lens

This is OM Zuiko 50mm x 1.8 at f=2.8. It's enlightening to see side by side results. The slight difference in focal length might be due to the positioning of the tripod, but more I suspect to the difference in lens configuration between the 'simple' 50mm and the 'complex' zoom (at 50mm). However there is a difference. More than this though is the rendering of colour and contrast. To my eyes the ZD rendering is more accurate, fuller and livelier.


No 7: ZD 50-200mm at 200mm, no teleconverter

This is ZD 50-200mm at full reach, wide-open. Sharpness/contrast/colour excellent.


No 8: OM Zuiko 200mm f4 prime telephoto

This is OM Zuiko 200mm x f4 wide open. It's not bad but a little less sharp and lacks some subtlety in colour and contrast.


No 9: ZD 50-200mm with EC14 at 200mm, EFL = 280mm

This is ZD 50-200mm + EC14 at full reach, wide-open (f=4.9) I can't really fault it.


No 10: OM Zuiko 300mm f4.5 prime telephoto

This is OM Zuiko 300mm x f4.5 wide open. Bear in mind the tendency for OMZ's to incorrectly expose, especially wide open. This has minus 2/3rds applied and accounts for most of the slight colour/contrast variance. Having said that there's little to choose between these images. The OM 300mm might look slightly sharper when reading 'Nishikoi' but remember it has an EFL advantage of 40mm over the ZD (600mm over 560mm). An impressive result - from both lenses. (Please also remember that performance varies from lens to lens and my OMZ 300mm might be better/worse than yours. I know owners who have made similar comparisons where the OMZ 300mm is easily out-resolved by the ZD.)


NB: The OM 300mm is a six element simple telphoto prime whereas the ZD 50-200mm is a complex zoom with 16 elements, 3 of which are ED glass and the TC14 adds another 6 elements; 22 bits of finely machined and polished glass through which the light must pass unincumbered.

Purely for fun: The OM 300mm in the 90's cost 900; the combined cost of the ZD 50-200 and EC 14 is 900; a remarkable coincidence? However the ZD is auto focus and an 'intelligent' lens that passes information to the digital body; the 300mm is just a lens/paperweight/doorstop (I jest).

But the purpose of the second part of this article is to compare an OM Zuiko Prime Telephoto with a Zuiko Digital Zoom lens AND a tele-converter. I believe these results show just how far the Olympus lens makers have come. Anyone with experience of analogue converters will be well aware of the dramatic loss of light and resolution that occurs when using them on film cameras, regardless of what the makers told us. (They insisted a 1.4X converter lost one stop, and a 2X lost 2 stops). I don't think I'm alone in disagreeing with their claims.

However, with the EC14 in conjunction with ZD lenses, there appears to be nothing lost in terms of resolution and a minimal loss of useable light. If this is what 21st century lens making combined with digital technology is bringing us then I can't wait for more!


CONCLUSION:

I'm converted too! These results are alarmingly good. I admit to being proven wrong. I genuinely thought any tele-converter would bring with it an inevitable loss of resolution. This is clearly not the case. Well done Olympus. For anyone like me who tends to use the telephoto end more than wide-angle, an EC14 is an excellent way of increasing your lens armoury at a 'reasonable' cost.

Prices: UK = 299 - 345; US = $385 - $425.


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Posted July 2005 14:04 Copyright © 2005 John Foster