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Home >> Photography >> Film Equipment Tamron
20-40mm f2.7-3.5 AF Background Long end to be covered but what about the wide end? For a time my widest lens was the Nikon 24mm f2.8 AF-D and it was a fine lens when I took the time to use it properly and get the most out its wide perspective. When I used it in urban settings such as photographing parades or just walking through interesting areas such as Chinatown, the 24mm lens was very effective for getting close while revealing a bit of background for a fuller shot. Good as this lens was/is, I still longed for wider coverage and preferably in a zoom lens so that lens changing and packing could be kept to a minimum. After trying out my friend Wilson's 20mm Nikkor, the extra wide perspective hooked me and I started my search.
Two obvious choices came to mind that would fit the bill, both from Nikon. The older and now discontinued 20-35mm f2.8 AF-D and its replacement the 17-35mm f2.8 AF-S zoom lenses. As much as I would have loved to have bought either one I immediately discounted them out of contention for one reason only, cost. These two lenses are very expensive in keeping with the price points for professional quality zooms. Although I have two other pro-quality Nikkor zooms, the 37-70 f2.8 AF-D and the 80-200 f2.8 AF-D, they're bargains compared to the wide angle zooms, especially the 35-70mm lens (sharp as any other quality pro zoom lens but priced far more sanely). The 80-200 is also priced quite nicely in relation to its Silent Wave counterpart. So with the Nikon zooms out I had to look at third party offerings from the big three of Sigma, Tokina and Tamron. Sigma was not a choice that I took seriously due its very bad reputation for mechanical integrity. From everything I've heard and read of Sigma lenses, they do seem to offer decent optical quality but the build quality of the lenses in general are just too suspect with many stories of continuous servicing required. My own offhand experience with Sigma was as an observer when I happened to be in my main photo shop of Broadway Camera and was waiting for my main contact person to finish his business with another client. A young fellow, probably about my age came into talk to another salesperson regarding his Sigma 80-200mm f2.8 HSM lens (Nikon mount). He was bringing it in for servicing and it wasn't something that I took much notice in until after Henry had finished and came to talk to me and suggested that I stay away from Sigma lenses because it apparently wasn't the first time the fellow had been in to service his lens. The next time I was back in the store for more items was about a month later and I saw the same fellow come in again with his Sigma lens for further servicing. I just hope that is was all under warranty for him. This experience as an observer of Sigma quality put me off of Sigma lenses despite the seemingly attractive lure of getting HSM (similar to USM and Silent Wave) in fast aperture lenses for less then the cost of original manufacturer's lenses. I did look at the Sigma 17-34mm f2.8-4 lens but it seemed pretty lightweight and its 82mm filter size was definitely not a plus either. It made me wonder why Sigma would have to use such a large front element in a variable aperture wide-angle zoom lens when Nikon and Canon could keep the filter size to 77mm in their constant aperture zoom lenses. End of story for Sigma and onto Tokina. Tokina is back in Canada again with a new distributor after an absence of a few years. It has a very good reputation for build and optical quality with the likes of Moose Peterson and John Herbst vouching for the company. I think that such glowing testimony has be taken with a few grains of salt though but acknowledgement is fairly widespread among amateur photographers using Tokina lenses and it seemed a worthwhile look. That is if any store actually had any to show. Widespread distribution of Tokina lenses is still low and most stores seemed disinclined to have more then two or three lenses in stock (if any for that matter). I could only go with third party reviews and lens comparison charts from the Internet. Aside from the Sigma only Tamron had very widespread distribution that I could actually handle some of the more interesting lenses. The die seemed to be cast for Tamron but I did some searching on the net for more information. Update November 5, 2005 - Tokina is not available in Canada anymore. The Tamron SP 20-40mm f2.7-3.5 AF lens is not one that has many reports written about it and almost no detailed reporting of its quality seems to be available (Popular Photography did review it and gave it a very positive grade). What I did find was that various users who reported their findings to the Photozone Lens Chart regarded it as being a decent performer and given its price point seemed to provide good value for the money as it was the most affordable of the three major third party manufacturers. The most interesting report was from Photodo, the website with the massive list of MTF graphs of many 35mm lenses. Of all the wide-angle zoom lenses that Photodo has tested the Tamron 20-40mm received the best grading, beating out such high quality offerings as the Canon 17-35mm f2.8L USM and the older Nikon 20-35mm AF-D. It of course bettered the Tokina and Sigma equivalents (surprisingly Tokina's cheaper 20-35mm lens ranked higher then their AT-X version). Most curious and the Photodo report stuck in my mind and was probably the final clincher for me to go with the Tamron lens. A good price offered me by Broadway Camera also helped me make that decision too. One aside here, Richard Martin, a regular contributor to the Canadian photo magazine Photo Life, uses Tamron lenses almost exclusively as can be seen in his comments to his published photos. I believe he shoots stock as well as doing workshops and it would certainly indicate that Tamron lenses are up to snuff as far as high quality optics are concerned if Richard Martin has such confidence to continue using them. Tamron SP 20-40mm f2.7-3.5 AF Zoom
Lens The 20-40mm lens cost me nearly $1k in Canadian dollars (and is actually a better buy then if I were to buy from the US, believe it or not) and while certainly expensive it is still only 2/5 the price of the Nikkor 17-35mm AF-S lens and half that of the 20-35mm (based upon B&H grey market price for the remaining ones in stock). It has a 77mm filter size, which is in keeping with most other pro-quality zoom lenses. The lens comes with a flower petal (or scalloped as some call it) bayonet hood and is packed in a leather bag. Size and weight are not bad at all with good heft and a more compact size then one would have expected for a wide-angle zoom lens but keep in mind that it is a variable aperture design so that allows the size and weight to be kept down.
AF speed with my F100 body seemed pretty good but most wide-angle zoom lenses are going to have pretty good AF speed due to immense depth of field and narrow focus throw. AF noise level was about average but it does remind me of recent incident when I had the F100 and the 20-40mm lens at work for a bit of lunchtime shooting. One of my coworkers who happens to use Canon equipment came down and checked out the kit and when he started to AF he mentioned how loud it was as he was not used to hearing so much noise when shooting. That hurt! As I mentioned earlier the noise level from the Tamron lens was not quiet but not loud either but compared to Canon's USM lenses any noise is loud. The 20-40mm lens is a variable aperture lens, which brings down cost considerably compared to the Nikon zooms and even against the Tokina AT-X 20-35mm f2.8 lens at roughly 50% more. Tamron has a thing for trying to eke out a bit more speed out of various designs in their history. I recall that they made a 180mm f2.5 lens and they also have a 24mm f2.5 manual focus lens still in the lineup. The 20-40mm has this very insignificant ability to go to f2.7 at the 20mm setting. I really don't know why they would bother with such a ridiculous aperture setting, as it most certainly is not a selling feature (at least not for me since I'd rather have the extra speed at the long end). Here is how the lens' minimum aperture changes as you zoom through its range:
As can be seen the range changes gradually and through most of the very important wide angle settings, a f2.8 aperture is kept with basically 28mm settings and up losing speed. Overall speed lost from widest setting to longest setting at 40mm is roughly half of a stop since f3.3 is the actual midway point between f2.8 and f4. This is based upon what Tamron would like you to believe as far as performance specs are concerned but as we all know performance specs are never exactly as published. Using Popular Photography's lens test we get these more exact specs for the Tamron 20-40mm lens (I've also added in the specs for the Nikon 20-35mm f2.8 lens for comparison purposes):
I won't get too much into the Popular Photography tests but in comparing the two lenses' SQF figures from Popular Photography, it does appear that the Tamron is actually a touch better performer then the Nikon lens when comparing large scale print sizes of 20x24 inches. This seems consistent with Photodo's MTF rankings and the Tamron's better performance figures then the Nikon. Incidentally, I've never used the Nikon 20-35mm lens but understand it to be an excellent performer. Another point to add is that Popular Photography states that it would take a full ten point difference for differences to be seen when comparing lenses and although the Tamron betters the Nikkor, the differences are not even close to a full 10 point spread. In essence, differences would not be observable if prints were compared side by side from the two lenses are far as sharpness is concerned. So how about that? A third party lens betters a major manufacturer's own very expensive version. What does it cost you? A little bit of speed at the long end of the lens, which in my opinion is not what these lenses are about. The wide-angle coverage is where it's at and from the technical side of it, there is little lost if anything. Giant killer status seems appropriate for the little Tamron that could. So why haven't we heard more about this Tamron 20-40mm lens? Why hasn't the photo world discovered this gem in the not so rough and accepted it into legend status? As I found out sharpness and technical specs aren't everything. The Actual Testing Part I I shot half a dozen rolls of slide film to introduce myself to the Tamron lens to see how it would fare by itself and in comparison tests against some Nikkor lenses I had available at the time. I'm not going to try and fool anyone and suggest that I'm a good lens tester because I'm not but I did the best that I could and I'll explain in further detail what and how I did things. The first roll of film shot was just to ensure that everything seemed to be working and to try out the various capabilities of the lens. Nothing was amiss from this introductory roll of film and I was satisfied with it but the tech geek in me couldn't leave well enough alone and I had to try and compare it to some wide-angle prime lenses that I was borrowing from my friend Wilson. These were the well-regarded 20mm f2.8 AF-D and the 35mm f2 AF-D. In addition I also had my 35-70mm f2.8 AF-D lens and then later on my new 24-120mm f3.5-5.6 AF-D lens. The first comparison tests did not provide me with much usable information due to a technical mistake on my part. I did the test in manual mode with a F100 body and used my Sekonic 508 meter to provide me with a reference exposure for the scene in question. The scene was my bedroom bay window with a wine bottle set up on the ceramic tile of the window's ledge. An old and not so attractive brass flowerpot with a vine like plant was placed beside the wine bottle. These were my foreground subjects and looking out the window, the background was my back driveway and a back alley access road. Beyond this were the neighbors' houses and various details of fences and garbage cans and other mundane items of suburbia. The focus distance was base upon the minimum focus distance of the Tamron lens and the two other Nikkors were also used at the same distance. Using the base exposure from the Sekonic 508, I worked through the aperture settings at full stop clicks and adjusted the shutter speed manually also at full stop clicks. The same values were used for all three lenses. This was my big mistake. Although I had come across the light transmissive qualities of zoom lenses versus prime lenses before in Bryan Geyer's Really Right Stuff catalogue, I didn't clue in that by using the exact same exposure value as would be dictated by logic, I was actually receiving very different results on film. This is because single focal length prime lenses are actually faster then zoom lenses set to the same focal length and same aperture due to all the glass elements in the way of the light traveling through a zoom lens. This difference can typically be about 1/3 of stop and this was what had happened after I received my slides back from the lab. The difference at 20mm was not so great that I couldn't glean something out of them but at 35mm the Nikkor prime lens was much faster then the Tamron, probably a full stop difference or more. The Nikkor 35mm so over exposed the background that it became a white wash and besides which the overall overexposure negated any meaningful comparisons anyway. What I got from the 20mm comparisons was a difference in colorcast. Looking through a 4X and 8X loupe I could easily see that the Tamron had a warmer balance then the Nikon lens. Trying to go beyond that obvious difference was a bit harder. Looking through the 8X loupe I compared the detail in the background fences in my back driveway and finally determined that the Nikon 20mm lens had better delineation of details at comparable aperture settings. This should be no surprise since we're comparing a high quality prime lens to a zoom lens and also keep in mind that the Nikon 20mm lens is only slightly less expensive then the Tamron 20-40mm lens. You would expect no less of a performance from the Nikon lens. The Tamron seemed to hold its own in the background detail and would probably do better against other comparable zoom lenses. As for the color difference, it was hard to say which would be preferable. If you didn't have the two to compare against each other I doubt that a person would ever be concerned and in fact some people may consider the extra bit of warmth in the Tamron lens to be beneficial since they wouldn't have to buy a warming filter. I didn't check the amount of warmth added by the Tamron but it is something I plan to do later on with one of my 81A filters. That was all I could get from the first set of tests and I determined that I would do the next set of test differently to minimize the effects of light transmittance. I would do this by using the F100 body in Aperture Priority mode and using the Centre Weighted meter. This way I would let the body determine the most accurate shutter speed for the parameters set. For the most part it worked well enough that I could do some meaningful comparisons but a poor choice of subject matter made the very wide 20mm comparisons difficult. Walking along the Burrard Inlet waterfront in Burnaby, I sought a subject matter that would have a multitude of detail. The running trail I was on had a resting area with a park bench set up for a viewing area over the water. When I came to this area I looked at the water and thought, "Who in the hell came up with the bright idea of putting a sitting bench to overlook some ugly industrial plant on the other side of the inlet?" No matter though as I unloaded my weighty Lowepro Pro Trekker backpack and set up my tripod, ugly as the industrial area was it had lots of intricate details that could prove useful for comparisons. The industrial plant was useful for the telephoto shots I took from the 120mm setting on my 24-120mm lens and my Bronica 150mm and 2x TC combination (about 180mm in 35mm format). The multitude of shacks, trucks, dockyard and background hydro tower lines made for easy discerning of the resolving power of my telephoto range lenses but alas was too far away for the wide angle lenses. The subject and testing procedure still gave me further insight into the Tamron 20-40mm lens though vis a vis the Nikkor lenses. Color fidelity was the other easily discerned quality. I kept flare to a minimum by placing my body between the sun and the lens so that they would have excellent shading. This was very important for the prime lenses as Wilson has not bought any lens hoods for his primes lenses and flare control would be important. What I found was that the Tamron lens had a duller presentation of the scene compared to the Nikkors including the Nikkor zoom lenses. In other words the color saturation was much richer with the Nikkors. Can we say that the Tamron is more accurate? Perhaps and if I'm honest about it, I should say yes, the Tamron seemed to have obtained a more realistic portrayal of the scene but this was with Fuji Velvia film, a film not given to realistic color balances. All the Nikkors lenses in which the sky was present had a more vivid blue and if you compared the Tamron shots to the Nikkor shots, you would be led to believe that I had used a polarizer with the Nikon lenses. I of course had not. The slides taken with the Nikkors also seemed "cleaner" and crisper and I was very surprised and appreciative of Nikon's consistency in keeping a family look throughout the lens range from a top consumer level zoom lens such as the 24-120mm lens through to its more expensive pro-oriented zooms and of course the prime lenses. Detail wise, I don't think the Tamron lens gave up much but often times, better or higher contrast is often mistaken for sharpness and perhaps that was what I was seeing too in the Nikkors, superior contrast and tone. Incidentally, although I tried to minimize the lens transmittance issue, the Nikon 35mm f2 AF-D lens still overexposed the scene compared to all the other lenses, probably between 1/3 to 1/2 a stop, indicating a need for exposure compensation or bracketing for very critical shots using this particular sample. It was after viewing the five rolls of slides from this last test that me led me to question the worth of the Tamron lens and thinking of the old adage, you get what you pay for. I cheaped out (if you can call $1k cheaping out) in favoring the Tamron lens and now I wonder if it will still have a place in my photo kit. I also shot some print film with the Tamron; some casual family shots as well a few for a wedding I shot. Honestly, I didn't care for the look and dull color but I attributed that to the use of low contrast films such as Fuji NPS, NPH and NHG and to the printer not doing as good a job as I would have expected. But now after seeing the color fidelity of the lens versus the Nikkors on slide film, I'm led to believe that the lens had a bigger role in the dull look. Another thing to point out and not solely negative on just the Tamron but of all wide angle lenses, is the edge distortion that becomes very apparent when taking photos of groups. The poor people at the edge of the frame will become widened and look far larger then they actually are. I knew that this would happen during the wedding I shot using the Tamron lens but given the tight quarters I was forced to work in I had little choice but to use the 20mm setting more often then I cared too because my other available lens for such shots, the 35-70mm, would have cut out half the group. Lens Test Part II I shot another two and a half rolls of film trying to see if the look of the Tamron would be consistent with another type of film. This time around I used Kodak E100VS with the half roll being Fuji Velvia. The Tamron gave the same kind of color and look compared to the Nikon lenses and when I did the tests with the last roll of Velvia, I tried to narrow down the warm cast of the lens. I mounted an 81A filter on a couple of Nikon lenses and compared the results to those from the Tamron by itself. This added bit of warmth or Tamron color is hard to describe. It is not the same type of warmth as an 81A as the colorcast seems a bit duller perhaps even muddier then the Nikkors with the 81A and without. The blue sky from the Tamron with both E100VS and Velvia turned out baby blue but flatter or more matte in finish whereas the Nikkors had a richer royal blue look and could be regarded as glossier. I think maybe that's what it comes down to, the Tamron is matte and the Nikkors are glossy. By itself the Tamron is not bad nor could it really be seen as wrong, just different. I imagine that the difference the Nikkors and the Tamron is what I would get in comparing Leica lenses to Nikkors. I hope to get that chance to see if the change is of the same magnitude as the difference between the Tamron and Nikons. General Handling The inclusion of the lens hood is a nice touch and is something that Nikon will not do except for their most expensive lenses, i.e. AF-S or VR. But the fit of the plastic lens hood on the 20-40mm is not smooth and is also not locking and while Nikon bayonet hoods don't lock either they are much smoother to mount and dismount. One very nice feature of the Tamron lens is the front lens cap. It has the normal push in tabs at the edge of the cap for releasing it but also in the centre of the cap so that the cap can be release without removing the lens hood. A beautiful idea that all other lens makers should copy. One thing that I've concluded out of all this is that Nikon lenses use Nikon glass. Let me clarify that astoundingly stupid sounding statement. Nikon lenses could be built by other manufacturers such as Tamron and Tokina but my testing of the Nikon lenses indicate a consistent family look. The results from the 24-120mm lens was the deciding factor because this lens as well as the Nikon 70-300mm 4.5-5.6 ED and the Nikon 28-200mm lenses are among those rumoured to be manufactured by Tamron for Nikon. The 70-300mm lens is a near copy of the Tamron 70-300mm lens and about the only major difference is in the filter thread size with the Nikon being a traditional 62mm size and the Tamron being a 58mm size. The Nikon 24-120mm and 28-200mm lenses use very similar barrels as the Tamron 28-200mm lens and it would certainly seem to make economic sense to reduce cost by using the same barrel for a variety of lenses. All three lenses share the same 72mm filter size and when zoomed out all three seem a bit too close for comfort. It could be that Nikon buys the barrels from Tamron but that's being a bit facetious and I believe that it is more likely that Tamron builds the lenses for Nikon in their factories. But the quality of the glass does not appear to be the same and it makes me question the potential quality of other Tamron lenses. I suspect that Tamron sources its glass from Hoya and I've never been entirely pleased with Hoya quality from experience with their filters. Conclusion I think if I never became overly curious and nosy about how the Tamron fared against Nikon lenses, I just might have been satisfied with the performance of it. But I must admit that I was never particularly comfortable with the idea of leaving Mother Nikon and buying a third party brand lens. This was a subconscious and probably conscious nagging little thing in my mind and perhaps what I was looking for was the excuse to go back to Nikon despite the horrendous cost to my wallet. Although, as I mentioned in the section about the second round of testing that the color seemed more neutral then the Nikkors, that was with Fuji Velvia. When using this film, neutrality is the last thing you expect and the last thing you want out this film. You want all the punch and saturation and vitality that this film will provide and the fact that it didn't do so with the Tamron lens would reveal the lens' major weakness. Even the variable aperture design of it does not bother me but I want consistency out of my lenses and if one is not consistent in providing me with a family look then it will become a nagging problem in my mind. The alternative though is not pleasant to think about, $2500 Canadian for the 17-35mm AF-S lens. Stay tuned for future developments. Update - the future development turned out to be Nikon's 18-35mm f3.5-4.5D AF lens.
Link to Tamron Japan and Tamron USA |
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Correspondence & About this website Copyright © 1998-2010 Edwin Leong |
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Early
on in my photographic journey, I realized that I was weak in two
areas of lens focal length coverage, the very wide angle and the
very long telephoto. The long telephoto is the key element of very
serious wildlife and sports photographers and poor old me just would
never be able to gather up enough pennies to buy into some gargantuanly
fast aperture, super telephotos. Even off-brand super telephotos
were still too expensive for me to consider. This poor boy's solution
will be to compromise and buy a very high quality off-brand 2X teleconvertor,
specifically the Tamron SP Pro, which is made for Tamron by Kenko
of the THK Group (Tokina, Hoya and Kenko). This teleconvertor would
be mated with the two-ring 80-200 f2.8 AF-D lens with the built
in tripod bracket to provide an autofocus 160-400mm f5.6 lens. Trying
to afford anything longer and faster would be grounds for divorce
and even poor boy has to acknowledge there ARE other things besides
hi-fi and photo equipment to worry about. 
Sized
up against the Nikkor 35-70mm f2.8 AF-D lens 
The
build of the lens seems fairly good with more metal then I might have
expected too, in fact I could not see any plastic being used in the
construction of lens save for the small window that shows the focus
distance (similar to that of the Nikon 80-200mm f2.8 lenses). The
lens caps and lens hood are obviously plastic but the build of the
lens and the feel of it was nice indeed, if a bit light compared to
my more stout 35-70mm lens. The zooming and focusing barrel are both
covered with rubber to provide good traction grip and both rings seemed
adequately big enough for quick use. One gripe though about the focusing
ring, it's too loose. The damping on this ring is pretty much non-existent
but I suppose we have to expect that if we want decent autofocus performance
from the lens and I can say that it wasn't isolated to this sample
I bought but to all other 20-40mm lenses made by Tamron. I briefly
played with a Canon mount version of the lens and found the manual
focus feel to be too loose and Popular Photography's review of the
lens also mentioned the same quality. This is a minor issue for users
who AF most of the time like me but various situations out in the
field when AF is not desired or required then a better damped focus
ring would be much preferred. 
In
the meantime a zoom lens covering very wide to near normal is convenient
and is a good fit with my 35-70mm and my 80-200mm. In fact the 20-40mm
is long enough that the 35-70mm doesn't even need to be used most
times as the 80-200mm is not so far away from 40mm to take over. The
Tamron balances nicely with the F100 and its only operational quirk
was the opposite direction for focusing to Nikon lenses. I also thought
the zoom direction was the opposite but my two-ring 80-200mm lens
actually zooms in the same direction as the Tamron while my 35-70mm
is a push-pull zoom leaving my 24-120mm as the oddball lens that zooms
in the opposite direction. 
