E-SYSTEM

ZD14-54mm and ZD11-22mm

that irksome focal length overlap?


INTRODUCTION:

There seems to be a disproportionate amount of overlap between the Zuiko Digital lenses 14-54 and 11-22. On the face of it anyone buying the ZD11-22mm is paying a whole lot of dosh for only 3mm of additional wide angle over that of the 'standard' ZD14-54mm zoom. [The angle of view for each lens stated by Olympus is (for 14-54) 75-23, and (for 11-22) 89-53. The simple maths therefore equates the 3mm of additional focal length to 14 degrees of angle of view]. Generally Olympus appears to plan their lens coverage quite carefully with little overlap between lenses which is surely the most attractive way to do it from the buyers point of view. So how come their first 'new' lens after the initial E-system introduction offerings was the widely overlapping ZD11-22mm? Perhaps the super high grade ZD7-14mm was especially difficult to design and manufacture to meet the demanding optical requirements of the 4/3rds sensor. Maybe Olympus had to compromise on the wide angle capability to bring about a wide angle zoom quickly enough to satisfy immediate demand. Perhaps Olympus could see that their expensive ZD7-14mm was not going to be attractive enough to coax large numbers into the 4/3rds fold. We just don't know.

The ZD11-22mm is rumoured (by some) to be in its death throws after only 2 years of production. Though I hope this to be untrue, I don't know if this is fact or fiction. If true one might be tempted to conclude that someone, somewhere, is saying "I told you so". Wide angles are expensive to manufacture; high performance wide-angle zooms even more so. A direct cost comparison between the ZD14-54 and ZD11-22 demonstrates the latter is around 30% more expensive and the wider and specialised ZD7-14mm is 2x the cost of the ZD11-22 and 3x the ZD14-54. The ZD7-14's extra 4mm over the ZD11-22 is mightily expensive per millimeter of additional focal length. I'm not the only one to have tussled with the problem of what to buy for wide-angle needs, I read about folks in the same position many times. This article is in reponse to several requests from visitors to this site for an opinion.

Both lenses set to 14mm; notice the front element position (height) is about the same.

But more so I've been asked whether the ZD11-22mm is worth having for the seemingly measly 3mm of additional width over the two 'standard' ZD zooms that start at 14mm. This small article endeavours to provide some facts for prospective purchasers to mull over before committing themselves. I bought my ZD11-22mm about a year ago following some issues I had with my ZD14-54 with which I was not happy. In all fairness Olympus did re-calibrate my ZD14-54 and I was much happier with its performance, but I suppose that niggling doubt had been planted. Going through that problem in some ways made it much easier for me to decide the ZD11-22mm was a lens I could easily justify. You may find it useful to read my impressions of the ZD11-22mm here.

My final comment in this introduction is that I'm impressed with the ZD11-22mm and whenever I use it I inevitably think that its focal length spread belies the numbers because at its widest it 'seems' wider than an equivalent 22mm. To settle this question in my own mind I did some direct comparisons. I mounted an OMZ 21mm lens on an OM1 (100% V/F image) and compared the V/F image to an E-1 (also 100%) with ZD11-22 at set at 11mm. I was careful to align both bodies and lens combinations as accurately as possible to the vertical and horizontal planes, and I paid particular attention to the getting film plane reference marks the same; of course this is not scientific or controlled, but I think it serves the purpose.

The V/F image with the 21mm OMZ on an OM body is indeed wider than the V/F image through the E-1 with ZD11-22 set to 11mm by about 5%, and, due to the 4:3 aspect ratio of the E-system, the E-1 provides more vertical V/F coverage (to be expected). However, without actually capturing the same image with both cameras from identical standpoints and comparing the results, I cannot be absolutely definitive. But the question remains, is it an optical illusion caused by the 4:3 ratio that makes the ZD11-22mm seem wider than it is at the widest end, or is there something else at work?

COMPARISONS:

I'm not going to bore you with specifications of both lenses - if you've got this far you will have already gathered this information. Nor am I going to compare the ZD11-22mm to the ZD14-45mm either; a comparison with the better specified ZD14-54mm should suffice. Obviously I can only compare similar focal lengths on each lens so I sample at 14mm and 22mm. My method is simple; tripod with head set to level, E-1 body mounted thereon, lenses attached, images taken using the remote, mode A set to f=3.5. First lens is the ZD14-54; shot one at 14mm (easy as that's its widest) and shot two at 22mm and checked for focal length on the monitor. Attach the ZD11-22; shot one is at 14mm and checked for correct focal length on the monitor and shot two at 22mm (easy as that's its longest). Nothing moves between shots so any variation is due to the lens internal construction. No settings are altered between shots.

TEST 1 AT 14mm:

Images are taken from the card and viewed in Photoshop. No post processing is done other than notation and re-sizing for the web.

If you examine the above two shots it is quite evident that at 14mm the ZD11-22mm captures a wider angle than the ZD14-54mm across the frame but not so evident vertically. Having seen just this difference, I set to in Photoshop and make as accurate an overlay as I can of the image from the lesser ZD14-54 on top of the wider image from the ZD11-22mm. I mark the wider image with yellow lines that demark the extremities of the less wide image to accord with my findings as precisely as I can. I then compute the image sizes so I can make some calculations to show how much additional 'scene' is captured and, in approximate terms, how this equates to focal length.

COMPARISON 1:

It's quite plain; at 14mm the ZD11-22mm captures more than the ZD14-54 set to the same focal length. The 8% difference equates roughly to just over one millimeter of focal length at this setting.

TEST 2 AT 22mm:

Images are taken from the card and viewed in Photoshop. No post processing is done other than notation and re-sizing for the web.

Again the difference in the amount of additional capture is easily seen across the image. The vertical difference is not quite as noticable but is there never the less. Once again I set to in Photoshop and make as accurate an overlay as I can of the image from the lesser ZD14-54 on top of the wider image from the ZD11-22mm. I mark the wider image with yellow lines to accord with my findings. I then compute the image sizes so I can make some calculations to show how much additional 'scene' is captured and, in approximate terms, how this equates to focal length.

COMPARISON 2:

Once again it's plain that at 22mm the ZD11-22mm captures more than the ZD14-54 set to the same focal length. The slightly less difference of 7.5% (could be down to my eyes or maths!) equates roughly to around 1.7 millimeters of focal length at this setting.

CONCLUSION:

No doubt about it, the ZD11-22mm has an optical construction that by default gives you wider images than the ZD14-54mm at the same focal length. Of course this only shows when you can directly compare the results, but it does explain why I (and many others) think the ZD11-22mm is wider than the numbers suggest and why it 'feels' different to the ZD14-54 in the overlapping focal lengths. By applying the approx. 8% additional coverage to the focal length spread of the ZD11-22mm and within the boundaries of this comparison only, the ZD11-22mm is probably more accurately described as a 10-20mm wide-angle zoom.

When making a comparison between the two lenses it may be fairer to the actual results you will get from the lens, to think in terms other than strict focal length spreads. If you are undertaking the comparison you may be better to think of the wide-angle zoom ZD (the 11-22mm) as 'different' from the standard zoom, capable of wide-angle captures of 10mm. I realise that we are talking about an average of one millimeter across the spread of focal length but in the context of this article this 'additional' coverage effectively increases the lens' wide capability by about 10%, a very welcome bonus. It may be fairer still to conclude the lenses are simply too different in their design and subsequent nature to be crudely linked (compared) by their overlapping focal lengths.

So there you have it. The issue of the ZD11-22mm's performance within overlapping focal lengths has bothered me for some time and I know I'm not alone. To have shown the coverage of these lenses at similar focal lengths to be different was quite simple to do and no doubt others may have made the same comparison. I present my findings to you as potentially interesting background information; I hope it answers some of your questions.

NOTE: This article seeks nothing other than to inform. Only you can decide what equipment you want/need for your use. Bear in mind I own these lenses, out of my own pocket; I have nothing to gain or lose by publishing this article, photographs, examples or opinion.


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Posted October 23rd 2006 14:30 Copyright © 2006 John Foster