I have a Nikon D750 body, with the 70-200 2.8 and the 200-500 5.6 Nikon lenses.

The two options I can think of are:

(1) Buy a 1.4x or 1.7x teleconverter for my existing D750 (FX).

(1.1) Approx. Price Nikon £400, Sigma £200, Kenko £100

(1.2) teleconverter add more glass, and may decrease sharpness and image quality. But they are significantly cheaper.

(2) Buy a D500 (DX).

(2.1) Approx. Price: £1,700

(2.2) The D500 will be better quality, may be handy to have a second camera with me to speed things up, but significantly more expensive.

There's obviously a huge price difference. I can afford it though, but at the end of the day it's hard earned cash, and it can always either be spent on better things, or simply saved.

I would like extra reach for wildlife photography. I do not make money from my photos, yet, but perhaps fit in the 'very keen professional hobbyist' category, if you can imagine such category.

So what I'm trying to conclude is:

(*) Is it worth buying a DX body to get that extra reach, or shall I go for teleconverter instead? And shall I simply buy a more modest DX body instead?

(**) if teleconverter, is there a huge difference between say Nikon and Sigma? And is the 1.7x worth the aperture and light loss for the extra reach?

Your thoughts and opinions are much appreciated. Thanks in advance.

  • \$\begingroup\$ We can't tell you if it's worth buying a second body: that's entirely up to you. We can possibly help with the teleconverter question, but your question is still very personal to you - we don't know how much the extra reach is worth to you. \$\endgroup\$
    – Philip Kendall
    May 11, 2016 at 14:26
  • \$\begingroup\$ I'm voting to close this question because it's too broad. There are several questions, with their own sub-conditions and contingent answers, to give a good answer suitable for Photo.SE. This question needs to be broken up into at least 2 questions (and verified that those questions don't have duplicates here). \$\endgroup\$
    – scottbb
    May 11, 2016 at 14:36
  • \$\begingroup\$ Since you don't talk about speed and do talk about reach, I assume you are only interested in using the 200-500? Also, I agree with scottbb that this is very broad. \$\endgroup\$ May 11, 2016 at 15:37
  • \$\begingroup\$ Are there times when you have the 70-200mm lens on your D750 and wish you had the 200-500mm mounted instead? Or vice versa? But by the time your get the lenses swapped the shot you wish to take is long gone? How valuable the advantage of having two bodies simultaneously mounted to two lenses in different focal length ranges is to you depends on what and how you prefer to shoot. For much of what I shoot it is essential. For you it may of may not be useful at all or may prove to be invaluable in terms of the shots you get that you would have otherwise missed. \$\endgroup\$
    – Michael C
    May 11, 2016 at 18:38
  • 3
    \$\begingroup\$ There is also a third option: just crop the shots from your D750. Either by manually putting the camera into FX mode or by cropping after the fact. Sure you lose a lot of pixels, but if you're only viewing at sizes that need those pixels. \$\endgroup\$
    – Michael C
    May 11, 2016 at 19:03

1 Answer 1


Here are points to consider when making choice:

  • 1x crop sensor + teleconverter is almost never better (have not seen counter-examples yet) than 1,5x crop sensor with same resolution and technological level + same objective without teleconverter. Teleconverter is extra glass and extra glass always means some light loss, some contrast loss and some additional chromatic aberrations
  • additionally, crop sensors usually have better SNR for a given FOV+DOF combination than their larger size counterparts of similar technological level. Specifically: even D7100 will slightly outperform D750 from this perspective, but D500 does not seem to be exceptionally better than D7200.
  • AF sensor sensitivities are rated in EV, and AF sensor of 1,5x crop body having same rating (-3 EV for recent prosumer cameras, check out the specs) will usually perform better with same objective than 1x crop camera with objective+1,5x teleconverter combo
  • many teleconverters will make AF work worse, be sure to check reviews of specfic models to find it out
  • there indeed is significant difference of image quality between teleconverters (even between 1,4x ones). I cannot advice anything specific here, I only suggest that you find samples from specific teleconverter or TC+objective combo before buying
  • good TC will always give you some additional resolution compared to digital cropping (because Bayer sensor does not have full chromatic resolution)

More about differences between D7100 and D7200 (dpreview has studio test scenes photos from D500 already).

If I was sure that I am fine with 7 RAW frames buffer of D7100, I would buy refurbished D7100 instead of 1,4-1,5x TC.

  • \$\begingroup\$ 1x crop sensor + teleconverter is almost never better (have not seen counter-examples yet) than crop sensor of the same size and technological level + teleconverter. You're saying that the same teleconverter behaves better on a crop sensor than a full-frame one? \$\endgroup\$
    – D. Jurcau
    May 11, 2016 at 20:21
  • 1
    \$\begingroup\$ @d-jurcau: sorry about that non-sense, edited (and edited again). \$\endgroup\$ May 11, 2016 at 20:23

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