What I look for in a lens.

Options, Options, Options.

With so many options available to us today, it can be hard to decide what is worth buying, and what you should stay away from.

Unless you can get your hands on the product and do your own testing before you buy, I recommend you do a bit of research online, looking at reviews and measurements. Measurements will tell you the technical specs, but you need to interpret that into your use case. No lens is perfect, so it is good to also compare lenses against each other. Reviews will tell you less about the technical performance but typically throws these lenses into a specific use case or side by side battle. Reviews can also be subjective or biased and is essentially the opinion of the reviewer, so have a look at different reviews for the same product.

Finding the info.

I personally use the following main sources of information and then a few others based on google searches.

  • DXOmark – One of the greatest resources of technical measurements. Do not look at the DXOmark score though. They have reviews too, but I never read them.
  • DPreview – A mix between some technical measurements and some reviews.
  • Tony&Chelsea Northrup – Reviews, technical info and tutorials.
  • PhotoRec Toby – Reviews, technical info and tutorials.
  • Matt Granger – Reviews, technical info and tutorials.
  • Ken Rockwell – Reviews and technical info.

Interpreting the info

When I look at specs or reviews, I always have my own use case in mind. I’m not going to use a fisheye lens for wildlife photography or a super telephoto lens for landscapes, you could, and the results could be interesting, but I rather look at the normal use case I intend to use the lens for. Eg:

  • Do I want it as a walk around lens with the versatility of being able to go wide and telephoto, without swapping lenses, while still being able to carry it for extended time periods?
  • Do I intend on using it in harsh environmental conditions and need good weather seals and limited lens swapping or simply a very sturdy build that can handle a few knocks?
  • Do I want to use it in studio only where I can add plenty of light and stop down to the sweet spot and do not care about weather seals or swapping lenses between different scenes?
  • Do I want to use it for low light work and really need a big aperture with good results wide open?
  • Do I want to use it for artistically blurred, highly manipulated, fine art work where neither depth of field, sharpness or noise really matter?
  • Or do I simply want a lens that delivers very good image results across it’s focal length and aperture ranges that I can use in almost any situation while worrying less about the settings and focussing on composition and my subjects.

Clearly for each of these use cases a different lens would be ideal, but we can’t afford to buy each lens out there. We end up having to make due with what we have and only ever buy lenses that we really need and use a lot.

On the next page we’ll look at what you really need.