One of the ongoing debates in the photography world is prime lenses versus the zooms. It has been going on since the development of the first commercially available zoom lens for still photography in 1959. Most of the early zooms left a lot to be desired but the technology has come a long way. Many of the zooms being produced today are outstanding pieces of glass. So what is the relevance of such a debate?
To an extent, this is a debate among those of us who first, have a love a gear and technology and second, tend to be geeky about the gear we have. I would always argue that you have to understand what your gear is designed to do as well as what it is capable of doing in order to push your creativity. This understanding will allow you to push beyond what has been done before.
I have the three standard 2.8 zoom lenses almost every working pro has, the 16-35mm, 24-70mm and the 70-200mm. They are great lenses and I could not do my job without them. But I have to say the Canon 100mm Macro IS f/2.8 is hands down one of, if not, the sharpest lenses I have ever had.
I had not thought about this debate in quite some time until I tried an experiment during a recent project. I was working on a project for a client photographing cocktails for part of an ad campaign. We were using the Canon 100mm Macro IS because we knew it was such a sharp lens. Then we put on a Canon 70-200mm IS f/2.8 for a shot to change it up a little bit. After taking 1 shot and looking at it on the monitor we put the 100mm Macro IS back on and didn’t think twice.
This is not a head to head test. The settings were not exactly the same as noted in the photo captions. The difference in aperture will make a bit of difference in the depth of field. There could also be some difference in the point of focus. Both images had minor color correction with the change applied to both images equally. Both images were cropped in as well to delete the negative space around the drink.
Give the variation discussed above I want to focus on the garnish and the rim of the glass immediately in front of it. I want to focus here because we can agree this are is in focus in both images. The image taken with the 100mm has better definition in the lemon and jalapeño. Further the rim of the glass right in front of said garnish has much better detail. The glass rim behind the garnish is out of focus in both images giving us some idea of where the point of focus is. We can also look at the rim on the opposite side of the glass to infer where the depth of field lies.
To further gain and understand of the effect of the difference in setting is put both of them into the DoA calculator to see what it spit out. The 70-200mm at those settings and assuming a shooting distance is a 1.5 meters the DoA is 6cm. The 100mm Macro is with the settings above and the same shooting distance of 1.5 meters you get a DoA of 10cm. The minimum focusing distance for the 70-200 is 1.2 meters so a working distance of 1.5 meters is about where I remember us being. The macro lens we could have been working closer. If we move into a distance of 1 meter the DoA drops to 4.32cm. Given all of this we obviously did not do a scientific test by any measure. What we do get is a good working example of using different lenses to accomplish the same goal.
With macro work we are always fighting to get as much depth and detail as possible, macro by its very nature makes this challenging. It is a pursuit where the little details make all the difference. This shows why using prime macro lenses will improve the crispness of the images we create. If you have both a zoom and a prime macro take some shots yourself and see the difference.