Sunday, June 30, 2013

Fast Standard Full Frame Zoom on a Budget: Tamron 28-75 f/2.8


In this post, I would like to have a second look at the Tamron 28-75 2.8, a lens that has been around for a while.  I used it when I had a Nikon D80.  I recently repurchased it to use it as a full frame lens for the Nikon D600.

BACKGROUND
When I moved to Nikon, the first camera I got was the Nikon D80, and the first lens I got for it was the Tamron 28-75.  I chose the Tamron on the strength of reviews such as from photozone.de.  Here is a sample shot (from July 2008!).  You can click on it for the full higher resolution.  BTW, all the shots here have had little editing, so that they are representative of what you can expect from this lens.

Nikon D80 + Tamron 28-75.  f/2.8, 1/160, ISO 100.
This shot had no additional sharpening applied.  Although I wouldn't say it's super sharp, it was sharp enough to capture pretty much all relevant details, including the texture and fine hairs of the skin.  Here is another one from August 2008:

Nikon D80 + Tamron 28-75.  f/2.8, 1/160, ISO 320.
As with the previous sample the Tamron 28-75 captured tiny details.  I was pretty happy with the Tamron 28-75 on my APS-C D80.  A couple of years later, however, I sold the Tamron 28-75 and got the then-recently released Tamron 17-50 VC, primarily because I wanted to be able to capture wider angles.

When I upgraded to full frame, I sold the Tamron 17-50 VC and for my standard zoom, I used a Nikon 28-70 2.8D on my Nikon D3.  I later upgraded to a Nikon 24-70.  Eventually, I found the standard zoom focal length to be too predictable, so I used it less and less, and after a while I sold the 24-70 because I could not justify the cost for the infrequent times that I used it.

Although I could not justify the ~$1500 or so (used) for a Nikon 24-70 that I would not use very often, I wondered whether the Tamron 28-75, which costs only a fraction of the Nikon 24-70, would be a practical alternative for those occasions when I might use a fast standard zoom.

TAMRON 28-75 ON FULL FRAME
Just because the Tamron 28-75 was pretty good on a 10mp APS-C sensor camera doesn't necessarily mean it would do as well on a camera with a full frame sensor, especially one with a higher resolution.  I couldn't find any comparisons between the Tamron 28-75 and either the Nikon 28-70 2.8D or the 24-70 2.8G so I had to take a leap of faith.  This time the version I got was the one without the built-in motor (because Tamron 28-75 users said that the non-BIM version focused faster than its BIM counterpart).

Body
The Tamron 28-75 is dwarfed by the Nikon 28-70
If you are familiar with the Nikon 24-70 and 28-70, the first thing you notice about the Tamron 28-75 is the size and weight.  It's very compact compared to the 24-70 and 28-70, which is surprising considering that it covers the same focal range as the latter and has the same constant f/2.8 aperture.  It is also much lighter (510g) than the 24-70 (900g) or 28-70 (935g).

With the lens hoods attached, the size difference is even more apparent
The 28-75 has a polycarbonate body with rubberized focus ring and zoom ring, and a metal mount.  It comes with a petal-shaped hood and a center-pinch lens cap. The build quality is somewhat similar to those of more recent Tamron lenses I've tried (18-250, 17-50 VC, 70-300 VC), although I would say that it seems slightly less solidly built than the 17-50 VC and 70-300 VC but better built than the Tamron 28-105 2.8.


There is a physical aperture ring with full stop detents.  The minimum aperture is f/32.  Because it has an aperture ring, it is possible to change the aperture in real time during live view with the D600 (or other mid- and low-end Nikon DSLRs).



The 28-75 has an internal focusing design, meaning that the front element does not extend or retract when the camera focuses, nor does the front element rotate.  The filter size is 67mm.



The lens extends from 3.6 inches (92mm) at 28mm to approximately 5 inches (127 mm) at 75mm.  There is a zoom lock to prevent zoom creep, although even without the lock engaged, I did not find any issues with zoom creep (unlike the Tamron 28-105 2.8).

Sharpness
When the Tamron is stopped down to f/4.0, it is quite sharp, not just in the center, but almost to the edges.
Nikon D600 + Tamron 28-75.  f/4.0, 1/1600, ISO 100. 52mm.
Nikon D600 + Tamron 28-75.  f/4.0, 1/1000, ISO 100.  52mm.
However, a constant 2.8 lens is intended to be used wide open at least some of the time.  In this regard, the Tamron 28-75 looks reasonably sharp wide open at about 12mp.

However, when images are viewed at 24mp at 100%, the Tamron doesn't look very sharp.  On the other hand, for real world shots, I find the sharpness is acceptable to me for photos of people (as opposed to objects or still life, for example), as long as you don't intend to print them at very large sizes.


COMPARISON WITH NIKON 28-70 2.8D

It so happened that after I got the Tamron 28-75, I saw a Nikon 28-70 for a very good price, so I repurchased it as well.  Here then are comparisons between the Nikon 28-70 and Tamron 28-75.  For each of them I showed the Nikon 28-70, then the Tamron 28-75, first at f/2.8, then at f/4.0.  I tested focal lengths from 28mm, 35mm, 50mm and 70mm.  In the case of the Tamron, I also showed 75mm.  All the shots here are available at their full resolution.  You can go to the web album instead.

Entire frame:

Web album here.

To me, the most obvious differences between the Nikon 28-70 and the Tamron 28-75 are the color cast and pattern of vignetting.  So far, all the Tamron lenses I've tried have a warm color cast, and this one is no exception.  The effect is somewhat similar to using a warming filter.  The Tamron is much warmer than the 28-70 (as an aside, the Nikon 24-70 also has a much warmer tone than the Nikon 28-70, although I don't recall it being as warm as the Tamron 28-75).

The Tamron has a little more vignetting than the 28-70, and when both lenses are stopped down, the vignetting on the Nikon 28-70 evens out, whereas with the Tamron, the vignetting remains noticeable.

The Lightroom lens profile for Tamron slightly overcorrects the vignetting, although the vignetting correction can be adjusted.

Crop from center:

Web album here.

The Nikon 28-70 is consistently sharper than the Tamron, though the Tamron is not bad, except at 35mm it gets a little soft.  There is a significant improvement in the Tamron by stopping down to f/4.

Crop from edge:

Web album here.

Wide open, the Nikon 28-70 is generally sharper at the edges than the Tamron, except at 28mm when they are both soft.  The difference in sharpness at the edges is most noticeable at 35mm where the Nikon is reasonably sharp while the Tamron is soft.  Stopped down to f/4, there is a significant improvement at the edges in the Tamron, and the Tamron becomes more similar to the Nikon at 28mm and 35mm, and actually is sharper than the 28-70 at 50mm and 70mm.


Color:
As mentioned above the Tamron 28-75 has a warm color cast.  When I'm taking photos of people, I find the extra warmth is more flattering for subjects, so I don't mind the color cast.


white balance with no adjustments - in an indoor gym
no adjustments to white balance - fluorescent lights

Focus Speed and Accuracy:

The Tamron 28-75 that I got was the one without a built-in autofocus motor, therefore AF speed depends largely on the body.  On the D600, the Tamron 28-75 focused quickly.  It's not quiet like the newer lenses with ultrasonic motors but it's fast.  As for accuracy, after I had dialed in the AF fine tuning, it focused reasonably well, although not always with critical accuracy.

Usually the Tamron 28-75 has accurate autofocus

Slightly backfocused
The Tamron 28-75 can autofocus while in live view on the D600, including full-time autofocus during movie mode.

Distortion
At 28mm, the 28-75 has noticeable moustache distortion (barrel distortion in the middle but flat at the edges).  The distortion is reduced at 35mm (slight moustache) and 50mm (slight pincushion).  There is pincushion distortion at 75mm.  Lightroom 5 has a lens correction profile for the Tamron that corrects the distortion. (I believe older versions of LR have the profile as well, but I don't know in which version the profile was introduced).

Here is a slideshow with the uncorrected shot, followed by the version corrected in Lightroom, at 28mm, 35mm, 50mm and 75mm.  Web album here.


Flare resistance:
The Tamron 28-75 has amazing flare resistance.  Even when the sun is in the frame, I only get a tiny blob of lens flare, with no observable reduction in contrast.

Here is a video that shows the Tamron 28-75's flare resistance.



no flare
Bokeh:
I find the Tamron 28-75's bokeh to be pleasant and smooth.  Bokeh is subjective so you don't have to take my word for it -- you can check out the shot below which is representative of its performance.

front and rear bokeh

CONCLUSION
If you want a fast standard zoom but have a limited budget, the Tamron 28-75 is a decent alternative, as long as you have reasonable expectations.  In my case, I very rarely make large prints (often, my images are only for the web) so the Tamron has adequate sharpness for me, even wide open.  As a bonus, the Tamron 28-75 is very compact and lightweight.  I also appreciate that it has very strong flare resistance, which is helpful for backlit images.  In my humble opinion, it is more than capable of providing me with good photos.

Before I show you some more samples, just a reminder that Google Reader will end on June 30.  You can transfer your RSS feeds to another aggregator such as Feedly (the process is relatively pain-free while Google Reader is still working).

RELATED POSTS:
Nikon 24-70 Review
Nikon 28-70 Review
DXOMark's Test Results for Tamron 28-75 for Nikon
DXO's Comparison with Nikon 24-70 and Nikon 24-85 3.5-4.5 VR

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