My new Tamron AF17-50mm f/2.8 Di-II LD Aspherical lens arrived the other day to replace the Sony DT 18-70mm f/3.5-5.6 kit lens I’ve been using. I’ve been meaning to replace the kit lens for a while; although adequate, I always felt that it doesn’t deliver quite what it should. So for a £300+ investment, I was keen to do some tests to see if the new lens was any better.

My initial reaction was that it was very heavy, much heavier than the Sony and very noticeable when hung around the neck with the camera. Its almost double the weight in fact, 430g vs 235g. The shorter minimum focusing distance is also noticeable and will be very useful.

A few quick indoor shots revealed that I was able to shoot a few stops faster with the Tamron; for example, given the aperture of f/2.8, I was able to shoot at 1/10” compared to 1/4” using the maximum aperture at the same focal range and ISO. I guess this should lead to much less blurry indoor shots without using the flash (I hate using the flash).

I mounted the camera onto my tripod and tried to see how much sharper the lens was. These two images were shot using both lenses stopped down to f/5.6 and at a focal range of 50mm. There is no post processing, and they are near 100% crops. Although a rather crude test, I think the Tamron clearly wins.

Tamron

Sony

I noticed that 50mm looked considerably different between the two lenses, with the Tamron wider than the two. Maybe the markings on the Sony are not quite accurate? So, intrigued, I took these tripod-mounted shots. Besides the Tamron being wider, the settings that the camera chose to marry to the f/7.1 aperture is quite interesting between the two lenses.

Tamron: Aperture Priority f/7.1, 1/15, ISO 160, 50mm

Sony: Aperture Priority f/7.1, 1/40, ISO 400, 50mm

So then I thought I’d see what the real difference between 17mm and 18mm was; afterall, there is often not that much difference between 250mm and 300mm. I took these to compare.

Tamron: 17mm (Program Mode Aperture-shifted f/9, 1/8, ISO 100

Sony: 18mm (Program Mode Aperture-shifted f/9, 1/5, ISO 100

I’ll need to use the lens in some real-world situations to see its merits. Perhaps over the coming Bank Holiday weekend. I will post some real photos soon.