Thursday 9 June 2016

Mastering Your Kit Lens - Part 4


The best lens is the one you have with you when the opportunity arises and your kit lens is often the perfect companion.



Yes your kit lens is much better than you probably think and today we will explore the upside of owning and using the cheap as chips but under-rated option.


The focal length Range

It’s no coincidence that most APSC kit lenses range from about 18-55mm (Equal for 28 to 75mm approx), camera makers and long term photographers worked out eons ago that this range covers 90% or better of what most people need for real world shooting. Micro Four Thirds camera makers tend to stick with the 14 to 42mm range which is the full frame equal of 28 to 84mm which adds just a nice little boost for portrait shooting.

Anything wider than 18mm  on APSC (27mm in full frame money) tends to create unpleasant edge distortions and egg shaped heads and 55mm is about perfect for normal portraits and slightly distant landscapes.  

The 18-55mm range is also about as extreme as you can go before compromises start to creep in, any wider or longer and you get the double penalties of more weight and greater cost and probably weaker performance at the extremes.  
Nothings impossible to solve of course but what price are you prepared to pay for it.

Yes sir, 18-55mm just works, you might think you need something wider or longer, but the occasions are actually rare for most photographers.  When I ask in classes, how many shots people take with the now almost standard 50-200mm kit tele-zooms I find few people have used them for more than just a few exploratory snaps.  Likewise I get plenty of students with super-wide angle zooms in the 10-24mm range but again accompanied by few actual photos, ultimately most students seem to find it hard to compose successful images on the wider view afforded by lenses in the sub 18mm (APSC) range.


The disposable Lens

Look at it this way, the kit lens is almost a free lens if you buy it with your camera, and even used ones one eBay go for almost nothing if you need a replacement.  So your kitty can be seen as disposable, no big deal if it gets dropped, lost, damaged etc thus it can used in risky environments or situations like drones with impunity. Of course it will likely be attached to your camera and that might be an issue if it gets hurt, so if possible let the lens act a sacrificial offering to the concrete, which oddly is often what happens in the event of a bad gravity spot taking hold of things at inconvenient moments.  

A couple of years back I knocked my A900 over whilst attached to a tripod (I tripped on the tripod, call me clumsy klutz if your like) .  Anyway there was good news, the lens mount (the bit the lens bayonet is attached to) acted as a fuse and broke on impact with a very solid cupboard, but the camera remained unharmed....nice one.  I cost me just $80.00 on eBay to replace the 28-85mm Minolta lens but a camera repair bill would have been far greater.


Weight

Most kit lenses are light, which might not matter if you’re taking the odd shot then resting your camera down, but should you wish to carry it around all day on a holiday trip, those extra grams will definitely matter.  I have had several Canon shooters tell me how much they just love their 24-70 Ls but then add they rarely carry their camera around with the lens attached cause its just too dammed heavy! So even if you get the sexy expensive glass maybe you should keep the kitty.


It’s Matched

Normally these days cameras perform all sorts of nifty adjustments during the jpeg processing stage to correct for the optical deficits of the kit lens, this could include: vignetting, distortion and CA removal and maybe other stuff as well.  If you have a  Canon camera and you buy another new Canon lens for example chances are it will do so for that lens as well.  But there is no promise at all it will do so with a third party brand lens and when using older pre-digital lenses it will certainly not be done.  Net result, when shooting JPEGs the kit lens might be the most fuss free option and even deliver better looking files out of the camera.


Resolution

Generally for regular shooting people are not making big prints, postcards and web images on facebook rule the day. These represent the lowest common denominator of imaging quality requirements  (with regard to detail) and neither usage will be impacted on by the difference between a fair kit lens and a really classy glassy.

Despite the generally marginally lower levels of edge resolution on offer via the average kit lens, for most real world photos it's just not a factor.  Consider for a moment, maybe your kit lens is a bit poor in the corners at 55mm but chances are your shooting something like a portrait and tack sharp edges and corners are likely to be a distraction anyway.  

In the mid range most kit lenses actually perform really well across the frame and moving to the wide end if you stop down to f8, it’s likely everything out to the corners will be adequately sharp for web and even moderate size prints.  You could also stop down to f16 and apply some clever sharpening to compensate for the diffraction effects in the editing phase in which case you will probably even get the very outer edges sharp at 18mm sharp.

The kit lens will not offer the same level of peak central sharpness as a great fixed focal length lens but if you’re not printing bigger than 8 x 10 inches again it will probably not be seen at all, unless your lens is a real stinker.   And if it is a stinker use it creatively and call the resulting images “art”.

Now heres a tip, most of the deficits in visible resolution can be made up via clever and subtle sharpening in post production, so spending some extra money on a good editing app and learning how to actually use it may reap a vastly bigger reward than buying an expensive new lens.

Equally you might also be surprised at just how much better your lens looks when you shoot RAW and use a "state of the art" convertor.  It sounds odd but often the in camera processing can accentuate the weaknesses in a kit lenses resolution via noise reduction and other adjustments that you have no access to control.


Sometimes Resolution Just Doesn’t Matter!

A few years back when I started working with iPhoneography I had an epiphany, 
often resolution just gets in the way, sometimes you just want impressionistic 
results.  Since that time I have deeply explored the world of iPhoneography and produced many artworks that were deliberately "not well resolved”. 

Your kitty can do much the same thing and with greater ease than an optical scalpel like a Zeiss Otus would allow. Resolution be dammed, embrace the fuzz, explore the blur,  get cosy with mush and most of all have some fun.


It probably has Image Stabilisation

When someone is severely afflicted with GAS (gear acquisition syndrome) or suffering from MEGS (Money Equals Great Shots) syndrome they will attempt to justify the purchase of that 35mm f 1.4 lens along the lines of “I can shoot under really low Light”.  Oh c’mon pull the other one....what a load of Bovine.

Sorry to upset you but here’s the thing you need to know.  Most of those fast glass heavyweights don’t have "IS" and "IS" is worth about 2-3 stops in terms of practical shooting under low light.  So a non IS f1.4 is about as practical as say a f2.8 to f4 lens with IS, but it gets even sillier.

In most practical instances an aperture of f1.4 has such shallow DOF that except for a few creative uses it is impractical to shoot much at that aperture and on top of that unless the lens is particularly well corrected  (read very expensive) it is unlikely to be critically sharp aside open anyway.

Inevitably these expensive lenses get used at f4 or smaller most of the time, but without IS they could well be delivering blurrier shots than the lower resolving but IS equipped kitty.

In any case even half decent cameras these days can shoot clean at crazy ISOs and that goes a long way towards making it possible to shoot in available darkness with slower lenses.

Of course I must add, if your camera has sensor based stabilisation then you can use any lens you like and still get the advantage, but that rules out Canon and Nikon stuff.  Sony A mount and Olympus shooters and a few Panasonic guys, you’re in luck!



What About Video

High quality pro-style video is typically shot with fixed lenses and various stabilising rigs to get that cinematic look, but for folk who just want to shoot the events of daily life such an approach is rarely warranted.  Image stabilisation is critical to get getting smooth footage without rigging and most kit lenses now offer this.

Beyond the stabilization kit lenses may offer other advantages for movie shooting, often the focus can sometimes be driven by a lever or control on the body  (such as on the Sony 3N) or even via a touch screen, focus point can also be often set and moved around via touch control as on the Olympus em10 mk ii.

And generally, and this is a big deal in video, all the above usually happens in near mechanical silence.


No Wide Apertures ?

Kit lenses of course lack wide apertures at either end of the focal range, that limits those creamy shallow DOF effects but then that look only really works for a limited range of applications and if you are like most non-pro shooters a quick examination of the exif data attached to your files will probably reveal the majority of shots you take are in the f5-f8 range. Which of course is right in kitty lens land.

There is in fact an advantage to a slower aperture lens, it’s a dirty little secret that purveyors of fine fast glass would rather not tell you about.  Fast glass typically 
suffers from focus shift as you close the aperture down, meaning you might focus at say f1.4 but then shoot at say f3.5, when the shot is actually taken the focus shifts a little and your final image ends up looking unexpectedly soft.

Smart cameras and owners have all sorts of ways of trying to get around this issue but it remains one of photography's most infuriating and misunderstood problems.

Kit lenses being slow almost never suffer any focus shift, so if you focus the wide angle at say f3.5 and shoot at f5.6 you can be sure the focus remained just where you placed it! That’s reassuring isn’t it?

And here is a big tip.....drumroll please.......if your kit lens is a true para-focal zoom, you can focus at the most telephoto setting, (manually of course) and then zoom back to the wide setting to take the shot knowing the focus has stayed put.  This is much easier than trying to focus at the wide end manually and will probably beat auto focus reliability at the wide end of the range as well. Sadly however most kitties are nowhere near para-focal so you need to test for it, having said that I have had two kit lenses that were very close to being para-focal.


So in summary there is a lot to grateful for when it comes to kit lenses, all the above makes them sound like a bargain, and in fact they are!


Next Post we start to get all creative.

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