70-300 lens compare to 2X teleconverter

Comments

• bruto

  August 2017

  Which 70-300? There are several from nikon and from others. The original Nikon 70-300AFD was good, but won't autofocus with a D3100. An old lens now, it's a huge bargain used, but no AF and no VR. The second 70-300G also won't auto focus, and is generally considered rather poor. It also has no VR. It was relatively inexpensive even new. The third 70-300 AFS-VR is very very good, will function perfectly, has very fast and accurate AF, and if you can afford it you'll like it. All three of those are FX lenses that work fine on DX as well. There are not three AFP- 70-300 lenses that may not work correctly on the D3100. One is FX, and two are DX, with and without Vibration Reduction.
  
  For extra reach without a great boost in overall quality, consider the relatively inexpensive 55-300DX. The autofocus is rather slow, but the optical quality is good, and the VR is very good. I have had this one for some years, and while not a stellar performer, it's decent. It has good reach and is a good complement to the 18-55 kit lens. It's entirely compatible with the D3100 and its ilk. I got it originally for the D3200 and use it now with a D7100. It lists for $400, and can be found sometimes used for less, and occasionally with rebates new.
  
  There are third party lenses also in this range, and I have heard that at least a couple of the major brand ones are pretty good. But when shopping, if not going for new, be very sure you know what you're getting, as most of these, like the Nikons, have gone through several generations, and features will vary.
  
  As a general rule, you'll get a little better performance from a 300 than from a 200 with teleconverter, or from cropping the 200 to 300 field of view, if the two lenses are comparable. But a very good 200 might do better cropped than a poor 300, or than a 200 with a poor teleconverter. But even if a 300 does not perform superbly at 300, it will likely be sharper at 200 than the 200 is, and quite decent in the high 200's. My 55-300 is a decent 300 but a much more than decent 250.
  
  A good 300 gives you the possibility to crop down to a longer effective length than you could ever get with the 200, but that depends a little on the quality of the lens and the density of the sensor. If you can afford to go longer you'll rarely regret it.
  
  I haven't any experience with current AF teleconverters, nor with how they interact with current AF zooms. In general, they vary from excellent to horrible, and some of the quality depeds on the lens they're used with, so if you go that route I'd make sure it's from a vendor with a good return policy.
  
  A good telecoverter can give you a nice boost, but remember that a 2x telectonverter will lose you a full two stops of lens speed. That means that if your aperture is 5.6 now, it will be effectively F11 with that teleconverter, and your autofocus, if it works at all, will likely be pretty poor. If you go with a teleconverter for the slow zoom, I'd recommend sticking with 1.5 or thereabouts, which will lose you only a full stop. Your camera should still be able to autofocus at effective F8.