Geeks With Blogs
Liam McLennan

I spent some time this afternoon testing lenses, just to see what my cheap DSLR lenses are capable of. I also wanted to know if my 50mm 1.8 prime lens produced sharper images than my 18-55mm kit lens.

My test subject was a book on a shelf. The cover features small writing with sharply defined edges. From where I was sitting the writing was too small to read, and my eyesight is ok, as far as I know. I shot one image with each lens both using the following settings: 1.3” ISO 400, f7.1.

Here are the results at full size:


The first is the 50mm prime and the second is the kit zoom.

At this size there is very little difference. For some reason the prime lens produced an image with higher contrast and more saturation.

The following screenshot shows both images at 100% ie one pixel on the screen for each pixel in the photo. Click to view full size.


The first thing to note is that they are both incredibly detailed. Remember that from where the camera was I could not even read the small text. At this magnification it is clear that the $150 prime lens is significantly sharper that the kit zoom. Of course, both are extremely sharp and the difference is inconsequential to an amateur photographer like myself.

While the prime lens does create sharper images I rarely use it because of its practical disadvantages. It is fixed at 50mm (obviously) so composition is more challenging, and at large apertures it is difficult to focus due to the extremely limited depth-of-field.

Posted on Monday, July 12, 2010 7:24 PM | Back to top

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