Old glass: Tamron SP 90mm f/2.5 (52B) macro

If you've been reading a while, you know that I have a weak spot for old things.  This includes old, manual-focus lenses -- some of which are older than I am.  Today marks another installment of my "old glass" series.  This time we'll feature the Tamron SP 90mm f/2.5 (52B) macro lens -- a well-built, well-respected beauty of a lens that works equally well for close-ups and portraits.

Tamron has produced a series of 90mm macro lenses over the years.  While many manufacturers have chosen to produces their mid-range macro lenses in the 100-105mm range, Tamron has always stuck with the slightly shorter 90mm focal length.  Don't ask me why, but it does set them apart from the crowd a bit.  I actually like it, because it better splits the gap between my 55m and 135mm lenses.  With the somewhat shorter focal length, Tamron billed it as a dual-purpose macro and portrait lens (competing with the traditional 85mm portrait length), calling it "the portrait macro."

Tamron's "SP" (Super Performance) line was introduced in 1979 as its professional series.  Even today, many SP optics rival their Canon "L" equivalents.

Tamron has produced quite a lineage of 90mm macro lenses.  The line began with the "52B" 90/2.5, introduced in 1979.  This is the version that I own and will discuss at length below.  The 52B was followed with the "52BB" 90/2.5 in 1988, which is optically identical, but with cosmetic changes (such as a 55mm filter instead of the 52B's 49mm).  Both of these provided a 1:2 (half size) magnification, but could do 1:1 (life size) with an extension tube or a 2X teleconverter.  The 52BB was replaced by the "72B" 90/2.8 lens in 1996, which could do 1:1 natively.  The manual-focus 72B was produced until 2006.  Concurrently, Tamron created an auto-focus version of the 90/2.8 macro dubbed the "72E" in 1996.  The 72E gave way to the "172E" in 1999, and finally to Tamron's current offering, the "272E" 90/2.8 macro lens, in 2003.  There's a great side-by-side listing, with photos, of all the Tamron 90mm macro lens variations on this web page.

While all of these lenses are highly regarded, the 52B is the best known of the group.  In most situations, it can go toe-to-toe with any other macro lens.

During the 1980's, most Tamrons (including the 52B, 52BB, and 72B) used the Adaptall-2 mount.  This was a generic mount, and Tamron then produced Adaptall-2 adapters for each of the various camera mounts (Nikon F, Olympus OM, Pentax M42, etc).  This allowed them to manufacture a single lens for use on every 35mm camera variety.  It also means that if you find a lens you like with the wrong camera mount, you need only acquire the proper Adaptall-II adapter to fit your camera.  My lens came with an M42 "Pentax" screw mount adapter, and I use it on my Canon 7D via one of my several M42-to-EOS adapters.  However, Fotodiox now makes an Adaptall-2 to EOS adapter that will mate these lenses directly to a Canon body.  Adaptall-2 adapters are also currently available for the following camera mounts:  Pentax K, Pentax M42, Nikon F, Sony Alpha, Sony E-series, and Olympus Micro-4/3.

  

The small, silver button at top left releases the Adaptall-2 adapter

The 52B is a solid, heavy, well-built lens, weighing in at 420g (14.8oz).  That's almost as heavy as my Yashica ML 75-150 zoom, which is nearly twice as long as the 52B.  Holding it in your hand, you get the impression that you could put it in a sling an fell giants with it.  It's 64.5mm (2.5") in diameter, and at infinity focus, it's just 66mm (2.6") long without the adapter.  As you zoom in close, the focus ring moves out away from the lens mount, and the front glass moves out at twice that rate (it makes more sense when you see the picture below).  This adds another 2" to the length of the lens.  More boring, technical specs can be found here.

 

The 52B at infinity (left) and minimum (right) focus.
I love how colorful old lenses were. Five different colors
of ink (not including black) grace the exterior of this lens.

The focus ring turns a full 270 degrees from minimum to infinity, allowing very precise focusing.  That, combined with the f/2.5 maximum aperture and the KatzEye split image / micro-prism focusing screen in my Canon 7D, make it extremely easy to nail perfect focus, even on moderately mobile subjects (I'm still not up to focusing manually for sports, though).

Minimum focus is just 390mm (15.3") from the film/sensor plane, or about 9" from the front of the lens.  At 1:2 magnification, you can fill the frame (on an APS-C crop sensor) with an object 45mm (1.75") wide.  This is what's known as a "vari-focal" lens, meaning that the focal length zooms in slightly as you focus from near to far.  It's not a big deal, but you do need to make sure you get your focus point in the right ballpark before you position the tripod and frame your macro shots.

Wide open at f/2.5

Aperture settings range from f/2.5 to f/32 in half-stop increments.  Its eight aperture blades are slightly curved, creating rounded highlights even at smaller apertures.  In fact, this lens produces some of the best out-of-focus highlights of any lens I own.  There's no rings around the edges, and the highlights near the corners of the frame are still almost perfectly circular rather than the squished footballs you get with most lenses.  It's not just the highlights, either.  This lens has some of the softest, creamiest bokeh I've ever seen (this from somebody who owns 30 or so lenses).

Purple spot, full frame at f/32.
This Mirco-Nikkor was used to
take all of the shots of the 52B.

The biggest down side for this lens is something that was never a problem back in the film days.  It comes from the fact that the rear element of the lens is perfectly flat.  When the lens is stopped down to small apertures (like f/11) and a bright light source is in the frame, light coming through the lens bounces off the reflective digital image sensor back toward the lens.  This happens with any lens on any digital camera, of course.  However, the flat rear element on this 52B then reflects that light back toward the sensor again.  The result is a round, purple spot right in the middle of the recorded image.  There are really only two ways around this:  1) use the lens at wider apertures (f/2.5 - f/5.6), or 2) keep bright light sources out of the picture.  The good news is that it's a rather well-defined circle, so it can be removed in post with good results.  More good news is that because it's caused by the shape of the rear element, stacking a teleconverter between the lens and your camera will remove the spot entirely.  You can read more discussion of the purple spot here.

Keeping bright light sources out of the frame is actually a good idea regardless of aperture, as this lens flares badly when shooting directly into the sun, even wide open.  If you want a nice, back-lit shot, pick a different lens.

Another less serious disadvantage is related:  the front element of the lens sits virtually unprotected at the front of the lens.  Direct light sources anywhere in front of the lens will hit the glass and produce flare.  There is no built-in lens hood, so you really need to use one that can screw into the 49mm filter threads.  Fortunately, these are inexpensive and easy to come by.  I own several, since 49mm is a common filter size in my collection.

One other idiosyncrasy I've noticed with my M42-mount version is that even when you use a flanged M42 adapter, the stop-down pin doesn't get pushed all the way into the lens (see the top left photo).  When the pin on the Adaptall-2/M42 adapter is pressed, a spring-loaded button is pushed (lower two photos).  This button in the adapter, in turn, presses on the exposed mechanism in the main lens (on the right side of the top right photo), when then stops down the lens.  The pin has be almost completely recessed in order to stop the lens down all the way.  With a standard flanged M42-EOS adapter, the pin only gets pressed far enough to achieve f/8.

 

 

The quick and dirty solution to this is to super glue the pin down, but this is non-reversible and eliminates the stop-down feature if you ever want to use the lens on an M42 camera body.  A better solution that I found is to cut off about 3mm from the end of the ink tube from a cheap ball-point pen.  Slit the tube down one side and slip it around the pin in the adapter, forcing the pin into the recessed position.  The lens will now always be stopped down, even when using a non-flanged M42-EOS adapter.  Of course, this wouldn't be an issue if you replaced the Adaptal-2 M42 adapter with a native Adaptall-2 EOS adapter.

Awesome subject isolation at f/2.5

All in all, this is a good lens.  It's very sharp, even wide open, and the creamy bokeh is gorgeous.  I actually use the lens more for non-macro shots than for macro work.  Paired with my Canon 10-22mm ultra-wide lens, it's part of my standard two-lens out-on-the-town kit.  The 90mm mild telephoto length, with its close-focus abilities and tight depth of field, is a great match for the 10-22mm for a car show or a day at the zoo with the family.

For macro work, I really only use this lens when I need something longer than my lovely Micro-Nikkor 55mm f/2.8 lens (as when photographing bugs or when I need to restrict how much of the background is in view).  Such was the case for my recent one-light pocket watch shoot (photo below).  Most macro work needs apertures smaller than f/5.6, and the purple spot can start to appear as early as f/8 if the in-frame light is bright enough.

52B at f/8.  No purple flare here.

Click for 100% crop at f/4, 18MP, no sharpening.
The full-frame shot was the same size
as the "purple spot" image above.

Here's a few other resources for this lens that aren't already linked above:

• A discussion in the EOS Manual Lenses Flickr group
• User reviews on the Pentax Forums lens review site
• Review of 52BB and 72B lenses, with good photos (translated from German)
• Tamron discontinued lenses list (including year discontinued)

If you're interested in seeing some more macro shots taken with this lens, check out another PRI post showing the organic patterns that form in the window frost in my 120-year-old home.

So there you have it.  If you want to learn more about using manual focus lenses on modern DSLR's, read this post.  Other manual lenses I've reviewed include my Pentax Takumar 50/1.4's and my Yashica ML 75-150/4.  All of the photos of this 52B were taken with my lovely Nikon Micro-Nikkor 55/2.8, which has occasionally required surgery.  If you've got any comments about this or any other lens, please speak up in the comments below.  We always love to hear from you.