I have purchased many used lenses over the last 10 years and never been burned. About two years I had the opportunity to get a 400 mm 2.8 VR. Not on the radar but it was a special situation. Too many $$. But got a great deal and love it. Amazing lens is all respects. Getting shots not possible with any other option. Really heavy but can be hand held for short periods with excellent results. My motto #1 know your seller (B&H) OR deal in person only#2 professionals usually take great care of their stuff #3 If it looks beat up/heavy used, it probably is so avoid it #4 drive a mutually valuable deal--- i.e. some one who really wants to sell is realistic on the price AND #5 Refurbished is not always a worth it. Good luck.

Echoing some of other comments I have read on this topic....Rockwell has been a valuable resource to me over the years. His published commentary on using a TC proved spot-on good advice in my case. Using a TC on any zoom is problematic. I tried both the Nikon's 1.4 III and 1.7 II (I think?). On my 300 F 4 tele, the 1.4 shows very little if any IQ degradation, even when cropped. On my 700-200 2.8 VR, very noticeable, especially when cropped at above 150. The 1.7 is not useful is most cases. The 1.4 on a 400 mm 2.8 is has performed really well. Good luck.

I bought a "like new" 300 mm, F 4 AFS (no VR) about four years ago for $600. Solid construction. Rockwell has a good write up on it.

www.kenrockwell.com/nikon/300f4afs.htm

It has been used A LOT on a D 4 for nature, wildlife, indoor/outdoor sports. Really sharp! Great results.

My situation:

I am a Nikon shooter (D4, D 610) and do extended vacation travel overseas. In 2017, that came out to about 5 months in New Zealand, Australia, and Thailand. Weight is an issue, but trying to keep track of too much photo gear moving from location to location every 3-4 days is proving a challenge. It is easy to loose stuff and I have! So, I consider weight vs. gear count of equal importance. About 60-65% of my shots end up falling into #1 50-120 and #2 at/above 300 mm focal lengths. My historical practice has been to take 3 lenses, with a TC. This is not working AND not crazy about TC s anyway. So 2 lenses will be the limit: 1 prime and 1 zoom. My trusty Nikon 24 mm 1.4 G is the prime. We are leaving for 6-8 weeks in Italy in April. So what do you think? Ken Rockwell liked this Sigma, and so do many of bloggers. All input is sincerely appreciated but a YES or a NO, with real world experience on this Sigma would really help. Thanks everyone.

Well he has been at it for about 20+ years and it supports his family fairly well. I guess he is good enough to figure out what he needs to do to get the job done.

Ditto on the 400mm 2.8. Much sharper than the Tamron OR Sigma. It's all about the $$$$

Thom Hogan is a very reliable source for me. His article on this subject is pretty spot on for my D 8xx experience. I owned a D 800 and have used a D 810. Tried things our with his recommendations, and verified his claims for the 24 f1.4, 400 f2.8, 24-120 f4, and the 70-200 f2.8 I. Google it and it pops right up.

While on a recent extended stay in New Zealand (quite cold 8 months of the year), I had a chance to spend a morning with a PRO photographer while he was on a shoot. His rule of thumb on the issue of cold was: "Once things hit 0 c - about 30 f - the number of bad things that happen increases A LOT". He listed a number of problems he has had while trying to take photos at below freezing. He was a canon user but the problems he had were probably not brand specific. So when it is below freezing, he packs it up and goes home. Hope this helps.

I have been test driving a set of the Yongnuo RF605N wireless trans receivers with D610, D4, SB600, SB700. Overall good -to- not so good -to- quirky. Great distance coverage. Sometimes a total unit reconnect with a camera re start is needed to get this things working. Then fine. Annoying. The supplied user instructions are total crap. Works fine with the SB700 on camera and off either camera. Does not sync with the SB600 at all, no matter what settings I try. NOT professional tools, IMHO.
Cheap at $33 so give it a try. Still testing.

I have owned and shot the D 610 and D 800 extensively, side by side for about 1 year. My D 800 output was amazing in IQ and color depth. However the transfer buffer speed got bogged down at lot. Not workable for sports, in my humble opinion. But my model also had some firmware quirks that Nikon could not remedy. (example: shut off for no reason). It was a fix work-around but real annoying. Overall, no real difference in the IQ. Sold the D 800. Very happy. Not one issue with the D 610 after 40000+ clicks and 5 months traveling overseas, in all weather conditions. There have been quite a few D 610 s on the NET that are virtually new (couple of 1000 clicks) for $700-850 +/-. Deal. Hope this helps. Good luck.

I have been using the MeFoto Global Traveler, aluminum for about two years. A little heavy side at just under 4 lbs but folds up really well into a small package. Cannot recommend it enough! It has been on TWO extended over seas trips (total 5 months), used it heavy wind, blowing rain,, snow, dust, and always worked well. VERY stable. The included ball head is also a keeper. Can hold up to 26 lbs. Running between $170-200 at B&H, Amazon, usual suspects. They also sell a lighter weight version at about $120. That one holds 15 lbs +/-. Good luck.

Did a similar comparison prior to a 3 week trip to Thailand. Being a Nikon shooter, the current travel photo solution is a D 610 with the 24-120 f 4. Camera plus lens investment, both bought pre-owned but never used: $1650. It was terrific for 3 months(16 K shots) while in New Zealand and Australia. The Fuji Xt20 with the Fuji 18-135 f 35-5.6 looked like a good option for saving weight and space. A friend of mine uses that camera/lens match up so we went out and test drove both set ups for a few hours. Overall, really darn close in performance match up. Fuji is great gear, no doubt.

In short (approximate)
- Fuji configuration (camera and lens) saves about 1 x 1 inch in Width and Height, and another 2 inches in depth.
- Fuji configuration is about 2 lbs plus a little lighter overall.
- Construction is really good
- BUT - give up FF, spend additional $1900 (roughly) while launching into a new line of Photo tech to maintain, AND if you have larger hands (I do) you might find a
extended usage "somewhat less than comfortable" (I did).

Conclusion: Stayed with the Nikon group. For me, the savings in size and weight for extended travel were not significant for the investment into new tech. Plus FF capabilities, fit, feel. AND the D 610/24-120 f 4 travels o k.

Hope this helps.

I live Hawaii. We have an "extreme" surf pro photographer who shoots big wave surfing, mainly huge (8-12 ft) shore breaks with a window of only a few seconds to nail the shot. Well known in the genre. Other worldly photos. These guys are totally crazy. Utterly amazing but terrifying to watch. Super fast, split second lighting changes, with huge contrast, unpredictable. He has tried just about every Pro and Pro-sumer camera in the Canon and Nikon line-up using ballistic, underwater camera housings. Quoting him: "If I did not have the D 500, what I do would not be possible" (Or something very close to that). Combo of size, weight, speed, low light capabilities, overall IQ, durability means he gets lots of keepers. Realizing this is an very extreme example, it may prove useful. Good Luck.

Echo on waiting to get an ideal Tripod. HOWEVER, everyone needs for a travel POD at some point. I have the Me Foto GlobeTrotter (weights in at 4 lbs) and holds up 26 lbs +/-. B&H has it for $173, including rebate. Rock solid. Excellent piece of gear. If you can do with a little less load capacity the RoadTrip holds about 17 lbs. and comes in at $120 (rebate included). So if the need is there, good deals.

I have been using a Me Foto (aluminum build, not carbon) for a little over a year as my go to travel pod. It did a great job on a three month trek through New Zealand and Australia, supporting my D 610 & D4, with an older (i.e. heavier) 70-200 V-R 2.8 Telephoto attached in all weather conditions. Some days the wind and rain were intense. Very stable. Quick to set up and tear down. Dealt with lots of water and dirt without a problem. Acceptable carrying weight at about 3.5 lbs and fit very well into every flight over head we encountered OR into a standard 22" roller bag. Also, found myself needing to do a shoot on the big Island of Hawaii requiring a Nikon 400 2.8 VR (a monster!), with using a D 810 and a D 4. We had some wind (8-10 MPH), and the Me Foto was the only tripod available. So with a Wimberely WH 200 attached we did our best. Hardly ideal. BUT the IQ from the effort was generally outstanding, with an acceptable-good number of keepers. No shaking. It's rated load weight is somewhere around 24/25 lbs, which makes sense considering the 400 2.8 plus a D4 is about 12-13 lbs per Nikon specs. Add the WH and your easily at 15-16 lbs. I would buy that tripod again in a heart beat. AND @ about $220-240 USD, a real price performer. HOWEVER, probably somewhat on the border for your needs. But it can work. Hope this helps.