Monday 10 December 2018

focal length - How useful is image stabilisation below 200mm, really?


Image stabilisation is all the rage, and hardly a new lens from Nikon or Canon is missing this "crucial" feature. To me this seems to be the new megapixel race (like when the manufacturers tried to overdo each other with higher resolution, they now try to do this with more (useless) features).


Especially for wide angle lenses like the new Nikon 16-35 I can't really understand what the fuss with VR is about. As a rule of thumb you should use 1/mm as shutter-speed not to shake pictures, for 16-35 shutter times of 1/16s to 1/35s should be manageable without problems.


At shutter speeds like 1/16s your subjects will blurred due be moving. Even more so if you really take advantage of the "4 more stops of light" VR might bring you. People will be blurred, because they are moving, talking. Leaves in a tree will be blurred because wind is moving them. Water will be blurred because of motion.


For almost anything below 200mm the only situation where IS/VR would be useful is some kind of still-life photography, like architecture. But this kind is better shot using a tripod anyway for maximum image quality and to help create a deliberate composition.


Of course IS/VR can (and probably should) be switched off when you don't need it, but why pay a premium for a stabilised lens when you can only use the advantage in very few situations? Why lug around the extra size and weight of an IS lens? Why tolerate the extra battery drain of the VR-system?


The same applies for IS-systems which are integrated into the DSLR body. I owned and used the Pentax IS system for a few years, and found it pretty useless in almost any situation I encountered since something in the picture always was moving and therefore being subject to motion blur.



Is there any real-world usage for IS below 200mm? Or is this mainly a marketing hype everybody is keen to attend?


Of course you can (and will) create some exotic settings where the extra stop of light is helpful, but do these rare settings justify the downsides?



Answer



As you say, the old adage, that you'd use the reciprocal of the focal length to avoid shaking (at full frame) still holds without VR: means 100mm = at maximum 1/100s ... or a tripod. Or 1/16 to 1/65 for your example.


I can't say 4 stops, but my experience with my Nikkor 16-85 (APS-C) says two stops. That makes at least 1/4 to 1/20 out of these numbers ...



  • ... and sometimes, blurred movement is part of the idea (I carry a ND8).

  • ... and sometimes cranking up the ISO is not possible any more. If you want a deeper DOF and/or take photos at low light-conditions (night, an indoors party): unbearable without IS/tripod.

  • ... and often people do not move that fast, 1/30 would suffice and comply with your ISO, but the 100mm focal lengths do dictate 1/100 for the nice portrait at the wedding-ceremony. (I do have a 17-50 2,8 for parties, but that makes another lens. Additionally: wedding-ceremonys of non-famous-people are better without a lot of flashes.)


    • (did you seriously put up the measure to 200mm and thus way beyond the portrait-focal-lengths?)



  • ... and very, very often tripods/monopods can't be used where you would like to. Be it due to local customs, the lost moment, local security, your own baggage-limits or that you simply do not want to lug around another kilo of a decent tripod everywhere. (My wife often bears the burden :) )

  • ... and sometimes you travel too and IS will certainly reduce this additional shake. See trains and ships and apply above ideas.


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