2017 update: I did not follow the ratings approach after some experimentation, this is an old article.
About lens ratings in general
Lens ratings have several advantages:
- Ratings are very easy to compare.
- They are very concise.
- Because it is much less work per lens I can cover many more lenses.
But ratings have many shortcomings as well:
- Reducing a lens to one single number will never do the lens justice.
- Ratings appear to be objective, but they are in fact mostly subjective. My needs can be completely different from yours so a lens which I rated 2/5 might actually better suit your needs than the one I rated 4/5.
- There can be a lot of sample variation between two lenses so if my copy is worse than most other copies my rating will be too low.
Despite their shortcomings I think this collection of ratings can be useful if you are looking for some orientation but they can’t replace much more extensive reviews.
About my ratings
Every rating is based on controlled tests and some to a lot of time spent using a lens (a good indicator of how much I have used a lens are my flickr albums, if there are more than 30 images in an album for a lens I have used it a lot).
None the less there are many reasons why it can happen that a rating is too good or bad, so if your experience noticeably differs from mine please inform me about that in the comments!
My ratings are based on my own needs and experience. My focus is on how the lens performs
- in a typical landscape scenario were it is stopped down to f/8 or f/11 and focused at infinity. Here I look for very good sharpness across the frame, distortion usually doesn’t bother me an CA to a certain degree is not an issue because it is easily correctable.
- as a portrait and closeup lens. Here I look how the performs when it is near it’s widest aperture at short to mid focusing distances. I look for good sharpness in the central 50% of the image as well as nice bokeh and the level of bokeh fringing. Coma at wider apertures doesn’t bother me.
- Other aspects which matter are flare resistance, lens focus throw length and feel of the focusing ring.
- Price isn’t taken into consideration.
How my ratings work
- 1/5: This lens good for very few applications and comes with serious defects.
- 2/5: This lens comes comes with noticeable limitations like very soft corners, very high CA and I would only recommend it for very special purposes.
- 3/5: This is a good lens which is capable of producing very good results but you should expect some compromise like low contrast and bad corners at the widest aperture and noticeably less sharp corners.
- 4/5: This is an excellent lens with very few faults, it ill be very sharp from corner to corner, have good (but not perfect) CA correction and nice or even excellent bokeh. Check out my Tokina 2.5/90 Macro review for a detailed review of such a lens.
- 5/5: A truly remarkable lens: it must show excellent sharpness even wide open, chromatic aberrations of every kind must reduced to a very low level, bokeh must be very good and mechanically it must be without fault as well. There are very few lenses which could earn this rating, think of a Zeiss Otus or CaNikons Super teles.