Tamron 35mm f2.8 Di III Lens

After all that talk the other day about street photography lets talk about a focal length that is synonymous with the street photography genre – the 35mm. In particular the Tamron 35mm f2.8 Di III lens.

Tamron 35mm f2.8 Di III lens mounted to a Sony A7r.

TLDR


Introduction

 

The Tamron 35mm f2.8 lens for Sony E mount cameras was announced back in November 2019 as part of a trio of prime lenses which share the same exterior design, construction, size, filter diameter and f stop. The other lens being the 24 and 20 mm. As lenses are becoming ever faster and even larger with price tags to match it is nice to see Tamron do something significantly different. The modest apertures and price tags may put off lens snobs, but they have enabled Tamron to give good optical performance at very reasonable price of $450 AUD. To many f2.8 may be disappointing, but honestly apart from bragging rights about shallow DOF we do not honestly need ultra fast lenses as todays cameras have absolutely astounding high ISO performance. When I started photography you needed fast lenses because film speeds were slow. I regularly shot ISO 25, 50 and 64 film emulsions and I wanted to do it handheld not on a tripod. Now shooting full frame digital at ISO 6400 gives the same image quality as as shooting ISO 64 film stock.

 


Specifications

A schematic of the lens construction.

 

Focal Length 35mm
Maximum Aperture F/2.8
Angle of View (diagonal) 63° 26′ (for full-frame mirrorless format)
Optical Construction 9 elements in 8 groups with 1 low dispersion element and 1 moulded glass aspherical element
Minimum Object Distance 0.15m (5.9 in)
Maximum Magnification Ratio 1:2
Filter Size Φ67mm
Maximum Diameter Φ73mm
Length* 64mm (2.5 in)
Weight 210g (7.4 oz)
Diaphragm Blade Number 7 (circular diaphragm) The circular diaphragm stays almost perfectly circular up to two stops down from maximum aperture.
Minimum Aperture F/22
Standard Accessories Flower-shaped hood, Lens caps
Compatible Mounts Sony E-mount

 

Golden Orb-Weaving Spider, Nephila edulis. Despite its size and their massive webs they are harmless to humans. Yellagonga Regional Park, Western Australia. The 1:2 magnification of the Tamron 35mm f2.8 makes this sort of photography a breeze.

 

For me the interesting aspect of this lens and indeed of its siblings is the cminimum focusing distance and it’s ability to shoot half life size. For me this makes them very suitable to creative macro and close up work. It’s not what you’d use to photography small critters as the lens has to be very close to the subject and will scare them off. For product shots, still life and another form of table shot photography it is a very interesting choice.

With a close focusing distance of just 15cm and a magnification ratio of 1:2 the Tamron 35mm f2.8 Di III is very suited to product photography.

Build Quality

In terms of build quality the Tamron 35mm the internet has largely been critical of it. The body is made out of some form of engineering plastic which you’d think had been manufactured by Tupperware judging by a lot of the reactions. Comparing this to recent Sigma lenses and Canon L lenses there is very little to distinguish the Tamron from the others. The only difference I can find without some sort of destructive testing is that the Tamron has a slightly more “satin” finish than the more “mat” of the Canons and Sigmas. The lens mount appears to be chrome plated brass which is nice, and there is an “o” ring which provides some semblance of sealing from the elements at the mount. There is no other weather sealing so I would say the lens isn’t really weather sealed at all despite Tamron’s claims. Tamron isn’t alone in this and I think it is high time the industry took a leaf out of Olympus’s book and actually stated to what level their products are sealed and give an IPX rating. Anything else is just weasley marketing BS as the majority of the camera and lens manufacturers state their products are weather sealed but won’t cover water water ingress under their warranties.  

The metal lens mount as a gasket to provide some weather sealing.

The lens is larger than other 35mm lenses of similar specifications and feels quite light in the hand, but it doesn’t feel cheap. It feels quite sturdy and well made. On the lens barrel there is only a ribbed focusing ring which is of the focus by wire type which means there is little chance of getting repeatable focus pulls using it.A the front of the lens the front lens element is well recessed and while the lens doesn’t focus internally it extends within that recess so it does not protrude beyond the front of the lens barrel. Like all Tamron’s mirrorless range so far the 35mm f2.8 has a 67mm filter thread. Tamron thoughtfully include a lens hood with the lens. Other manufacturers please take note – if Tamron can include a lens hood with its budget lenses there no reason why you can’t. I’m looking at Olympus and Canon here. The lens hood warrants some discussion here as it is quite an interesting design. It is not the conventional bucket or petal shape. Instead it is like a plastic blank that has had a rectangular hole cut in the front and it is very effective at preventing flare and would also provide a degree of protection for the front element. The hood is threaded to take 67mm filters which means that you don’t have to remove it if you want to use a polarising filter. Somebody at Tamron has been doing some thinking. The hood bayonets into place.

The front lens element is well recessed.

Optical Performance

The Tamron 35mm f2.8 has built in lens profiles that are applied to jpgs and RAW files if so selected in the camera’s menu. I’ve opened the files in both Lightroom with the profiles switched on and then in RawTherapee with no profiles. 

Click on the chart to see larger.

In terms of sharpness well at f2.8 at the centre of the image the lens is nicely sharp and contrasty. At f4 the it reaches its best performance and stays there to f11. At the edges wide open it isn’t quite as sharp as the centre, but by f5.6 the edges are as good as the centre. The old adage of stoping down two stops from wide open to achieve optimum performance certainly holds true of this lens. By f16 the image starts to soften as diffraction rears its ugly head.

In terms of optical aberrations well once the lens profile is switched off there is very slight evidence of pincushion distortion and vignetting. At f5.6 the vignetting disappears. A small amount of lateral chromatic aberration can be seen, but it is so slight I had to magnify the images to 300% to see them. Easily fixed in Lightroom. With a maximum aperture of f2.8 longitudinal chromatic aberration is not a problem. It is really fast apertures of f1.2 and f1.4 that really cause problems with this.

Without a lenshood the lens exhibits quite pronounced ghosting flare. Note the discolourateion on the tree trunk halfway down and the polygonal shape on the trunk at the bottom of the frame. At f22 the sunstars are pronounced, but aren’t that well defined.

Flare resistance is a bit on the pedestrian side without the lens-hood with ghosting visible. The lens-hood is included in the box for a reason so use it. The seven bladed iris produces what to me are quite attractive sun-stars. Speaking of how the lens handles specular highlights the bokeh is not what I would call thrilling but it is not offensive either.  Wide open in the centre there are round balls with faint onion rings present from moulded aspherical element. I suppose the final polishing wasn’t as smooth as that on more expensive lenses as a cost cutting measure. The edges of the balls are not smooth, they have a fuzzy appearance as the light bleeds into the darker areas which is a form of halation. At the edges of the image the bokeh balls take on that elliptical cats eye shape. By f8 the bokeh balls take on a definite polygonal shape.

In the bokeh test we can see quite nice round balls in the centre of the image wide open, but on closer inspection onion rings are present and the edges have a fuzzy appearence to them. At the edge of the frame the balls have a definite cats eye shape. As the lens stops down the bokeh balls take on a polygonal shape which is really apparent from f8 and beyond.

 

Click on the image to see larger.

Comparison 

The Olympus OM Zuiko 35mm f2 mounted on a Sony A7r.

Is a cheap auto focusing lens worth getting over a classic manual focusing version? Well to find out I’m comparing the Tamron 35mm f2.8 lens to the Olympus OM Zuiko 35mm f2 lens. Forty five years separate the two optical designs and a lot has changed. There are several different version of the Olympus lens. It had a long production run from 1974 to 2002. I’m using a later multi-coated version. This MC version is 43mm in length, 240g in weight and has a filter thread of 55mm. It has an optical construction of eight lens elements in 7 groups and a minimum focusing distance of 0.3m. When it’s performance is studied we can see there is slight barrel distortion evident in the test image. CA is present when wide open and clears up on stopping down Wide open the lens is quite soft and lacking in contrast both in the centre and at the edges. Both sharpness and contrast improve in the centre when stopped down to f8. The edges show some signs of improvement but not as much as the centre. 

Our test subject for the comparison.

Comparing the two lenses in an actual real world shooting scenario we can see that with both lenses set to an aperture of f2.8 in the centre of the frame there is virtually no difference between them and I’d say they they are equal. In the corners, however, it is a very different story. The Tamron has a good level of sharpness while the Olympus is very soft. Stopping down to their respective minimum apertures – f22 for the Tamron and f16 for the Olympus -we see again in the centre that there is just a very marginal difference. In the corner the Tamron is better by a gnat’s whisker. Just remember that the Olympus was given an advantage. The Tamron shot wide open at f2.8 while the Olympus was stopped down at to f2.8 allowing an improvement in optical performance. At f16 the Olympus didn’t suffer the amount of diffraction the Tamron did at f22.

A comparison between the Tamron 35mm and the Olympus 35mm at f2.8. Click on the image to see it larger.

 

The same again but at f22.

Conclusion

When Sony launched the original A7 and A7r in 2014 critics poured scorn over the nascent system by saying there were no lenses. Early adopters divided into the system and tried their hand at adapting lenses they did have to fill the gaps in the line up. Fast forward to 2021 and Sony have done a tremendous job at fleshing out their line up. But the most significant thing is that Sony allowed third parties to access the lens mount protocols and this has meant that are lenses that range in price from decidedly wallet friendly all the way to those that would make a trust fund baby wince. At the time of testing the Tamron lens is selling for $350 AUD (which is the equivalent of being given away with a McDonalds Happy Meal in the USA). Looking on EBay the Olympus is selling for between $300 to $700 AUD depending upon condition and version. The version I have would count as a mint late model which would place it in the upper range. So the question is whether having a new autofocus  lens is worth more to you than having a potentially more expensive 20-40 year old lens. Well I had the Olympus lens left over from OM film days (along with quite a few others) and I actually got a secondhand Sony A7r camera so I could use the Olympus lenses. I was very happy with that arrangement. The Tamron registered on my radar because of its macro capabilities.

So you want to go full frame mirrorless with a 35mm prime lens  but don’t want f1.2 lenses or can’t afford them then buy the Tamron. Don’t want want to carry around a lens that is capable of blocking the Suez Canal buy the Tamron. It is nowhere near a perfect lens. It is a modest lens, with a modest price and with a better than modest performance. So with what it costs and with what it can do it is a great buy.