How To Do A "Quick And Dirty" Lens Test
I have the new kit 12-60 panasonic lens, bought as a filler for my school work (mostly as a wide angle) and the Leica 12-60 is on the way. I bought this lens based on a previous test conducted at the shop I worked for, comparing several lenses with a wide element (15 Leica, 12-60, 14-140 and 12-35 Lumix, 12-100 and 12-40 Oly) and the 12-60 surprised. Only the 12-100/40’s and 15mm clearly beat the pack, the 12-35 was dissapointing for the money.
So, how do you calm the jitters and check that you have a good copy of a lens?
With zoom lenses, the reality is most have some slight optical inconsistency, but modern glass is seldom off kilter enough to be a real issue. For more on this the http://lensrentals.com blog has some great, but scary articles.
My tests, done “in the field” are simple checks to make sure the two most likely issues (three for SLR shooters*) are picked up quickly so you can either exchange the lens or more likely, just be aware of them.
De-centering.
When up to 20 elements of glass are layed down in the barrel of a new lens, there is a slim chance that they will have one or two not perfectly aligned. Designers take this into account and modern manufacturing tends to mean most of a batch are nearly idential, but batches may vary slightly, especially when a line is new.
My tests (EM5 Mk1, 12-60 kit) are done hand held, shifting the focus point onto the corner subject (the pillow on the empty chair).
Corner aligment at 12mm wide open (no post applied apart from C1 import and cropping).
Apart from colour shifts due to my non-scientific process, there seems little difference. If any corner is different at all, the lower left maybe slightly less controlled, but still falls within perfectly acceptible levels. If this was the best the lens could manage it would be fine. The fact some corners seem maybe even better is a win.
Now 60mm wide open
Again, no science applied here, but good and even performance.
Bokeh? Not really a big selling point for a slow M43 zoom lens, but the relality is, most photos have an element of Bokeh (it’s in the definition), and some of my favourite results have come from my slowest glass.
Background Bokeh at the long end is very pleasant. In reality, semi focussed Bokeh is possibly more imporrtant than “full blurr” Bokeh. With maximum blurring, post can easily be applied. When the background is included in an even semi coherent form, poor Bokeh behaviour is less fixable.
Foreground at the wide end is nicely smooth in rendering, making wide open use easier. Focus was on Daisys’ face at f3.5. “Invisible” transitions are ideal here, something the 17mm Oly is good at.
The best thing about the Bokeh is, when I tested the lens it went pretty much unnoticed.
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Sharpness. I am used to even the cheapest M43 lenses being sharp enough for most tasks, but this lens has shown in my own previous tests and those done by many others, to be very close to the Leica in base sharpness. The question is, what “type” of sharpness is it**?
So, who decides to do a sharpness test at ISO 1600, hand held at 1/15th with a 13 year old camera? Apparently I do. The base image. The flat colour is down to the environment, the camera and ISO, but partly the lens with its “mild” colour rendering.
On the focus point (hair in front of the eye), sharpness is more than enough for publication even at big sizes. No post applied. Bokeh smoothness again shows up here.
Pushed a little with globally added Clarity and Sharpening. This is similar to my 40-150 kit. There is good micro contrast, decent base sharpness and control of other clarity reducing elements. Like the 40-150, it does not need much extra post applied. In Lightroom, I found some lenses struggled with the noise to sharpness balance, but C1 hits a decent level in both. The EM5 Mk1 has a “simple-sharp” sensor, an honest, pleasantly film-like look, but not as delicate as later models, so it may be the camera (especially at ISO 1600).
Other things?
As I tested, I looked for chromatic aberration, flare and glare and other obvious issues and found statlingly few. I was aware the Lumix lens is possibly even better than the Leica at handling flare and would believe it.
From my first day with it, when the sun was shining. Most of my lenses struggle with this one, a good excuse to avoid cleaning the window…... . For context, this was uncomfortable to my eye.
If I look at this lens in relation to it’s intended role, it will be better than fine.
As a wide angle filler, a good light “one lens” and studio/travel work horse, it has all the right characteristics. Would I use it for formal group shots of the school body, to cover jobs like my Telstra portrait shoot, street and travel portfolio work? Absolutely, but I have specialist options for each circumstance. If pushed it would be more than adequate. This lens has reminded me to use my “lesser” enses more. No-one but me knows the difference.
Why the Leica? Build, aperture choice (especially for video), slightly superior mechanics (again for video), the ability to cover the ranges in two kits. Basically that is it. This lens was the smart buy, something I am always happy to do. the Leica is the sensible buy, but always a higher risk to reward ratio.
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Lens speed, the elephant in the room is always a consideration. Not much is enticing about employing it for low light action (this is when the full frame users start to pull ahead), but aside from that, it has few real weaknesses. At the wide end, it is fast enough and for the uses it will be put to and if used in the studio, speed is irrelevant.
Importantly, it works efficiently within the envelope of what it offers. There is nothing more frustrating than an already conservative lens that has to have special considerations applied. If it only offers f5.6, then f5.6 needs to be useful, otherwise it is actually an f8 lens. I have come across this before and it is a fail mark***.
Would I spend $600au on it? No, I would spring for a little more and get one of the many other standard lenses available like the Oly 12-45 f4, but for $100 in a kit, it is a steal. It’s even weather proof and dual stabilised.
*Calibration of lens to camera focal plane was a common concern with SLR cameras, something I struggled with regularly, but off the sensor focussing in mirrorless cameras has removed this as a consideration.
**To me sharpness comes in several forms based on sensor and lens, from simple/honest to complicted/delicate and results in lenses that do or do not like sharpening, contrast or clarity of different sorts applied. This is subjective, personal even, but a real observation from seeing many lenses and cameras.
***My Canon 17-40 f4L especially on a full frame camera had several “exceptons” including a performance dip in the mid range, effectively zero resolution in the corners wide open at the wide end some CA etc. This did not stop being one of the most popular lenses in the Canon range, but it needed to be used intelligently.