Thanks all for the input. My wife actually does have a bridge camera. Not sure the model, about a 5 year old Nikon that I believe is ~600mm equivalent. I admit it is great in certain situations. The zoom is tremendous. Often though I am frustrated by it in how slow it is to zoom, autofocus, and release. I think once used to zooming/AFing/releasing with a DLSR, it's hard to enjoy doing the same with a compact (my opinion, I realize not shared among most). Much of my own frustration comes from fast-moving birds in flight, or birds that are skulky and move in and out a sight very quickly. At this point, I think I have gained a decent understanding of what the different types of solutions offer.
I still remain curious: can you get sharper cropped images with more MP? If not, what does high resolution do?
HeadWest ,
The sharpness has to be there to start with. To get this in all conditions requires really high quality fast glass, accurate AF, and a sensor that performs well at the given ISO, the right shutter speed and good technique. You will get larger details with cropped images, but they may not necessarily be better (still it could help in making an Id though).
For example, the Tamron G2 and Sigma C 150-600 f6.3 exhibit a bit of relative image softness beyond 500mm ie. the last 100mm to 600mm - the most useful bit! Thus Nikon's 200-500 f5.6 zoom would likely serve you better, though it is ~10-20% heavier, and ~ 40% more expensive than the Sigma, but about line ball with the Tammy. At f5.6 it is a half stop faster than both.
Even though the options you will be considering have Vibration Reduction (or Image Stabilization) to help with sharper images at slow shutter speeds, a higher shutter speed (~1/2000th of a second or quicker) is needed to reduce motion blur of the subject itself - Birds In Flight, or little geewhizzits that can't sit still, dart their heads and tails from side to side, or flit from branch to branch. Therefore you want the fastest, longest, best quality glass you can afford and can carry.
The new Sony RX-10 IV is perhaps the first bridge camera to offer DSLR levels of performance due to its new phase detect AF system which borrows heavily from the algorithms of Sony's flagship mirrorless models. It will handle BIF shots that other bridge cameras find difficult or impossible (giving the typical frustrating bridge camera experience that you mentioned). It's 20MP stacked BSI-CMOS sensor is cutting edge technology, and the 600mm equivalent f4 Zeiss glass is absolutely top notch. It will also shoot 900mm @10MP, and 1200mm @5MP. Its minimum focus distance is only 0.72m too. Check out its performance on BIF in this review here - I think you will be quite pleasantly surprised:
https://www.cameralabs.com/sony-cyber-shot-rx10-mark-iv-review/
Also, check out the review of the superceded MkIII version (note the IQ is comparable, but the AF on BIF of the MKIV will be a quantum leap ahead) and look at the zoomed and heavily cropped photo of the high altitude jet airplane and see if that is enough IQ for a record shot!
http://www.kenrockwell.com/sony/rx10-iii.htm
As I see it, your choices (for a given minimum BIF, quality, reach benchmark) are going to come down to 3 things - weight/size/cost.
1. Sony 1" 20MP RX-10 IV 24-600mm f2.4-f4 ..... 1.1kg ..... 145mm length .... 1700 USD.
2. Nikon APS-C 24MP D7200 (765gr/$900) + Nikon 300 PF f4 (=450mm equiv.) 755gr ..... 1.5kg ..... ~205mm length ..... 2900 USD total. NB. using 1.3x in-camera crop gives 585mm equiv. f4 @14.2 MP
3. Nikon APS-C 24MP D7200 (765gr/$900) + Nikon 300 PF f4 (755gr) + Nikon 1.4x TC III (=630mm equiv. @f5.6) ..... 1.7kg ..... ~230mm length ..... 3400 USD total. NB. using 1.3x in-camera crop gives 820mm equiv. f5.6 @14.2 MP
4. Nikon APS-C 24MP D7200 (765gr/$900) + Nikon 200-500 f4.5-f5.6 (=300mm-750mm equiv.) 2300gr ..... 3.1kg ..... ~325mm length ..... 2300 USD total. NB. using 1.3x in-camera crop gives 390mm-975mm equiv. f5.6 @14.2 MP
Compare these to your suggestion of the D7200 + 80-400:
5. Nikon APS-C 24MP D7200 (765gr/$900) + Nikon 80-400 f4.5-f5.6 (=120mm-600mm equiv.) 1570gr ..... 2.3kg ..... ~260mm length ..... 3200 USD total. NB. using 1.3x in-camera crop gives 155mm-780mm equiv. f5.6 @14.2 MP
All these rigs will perform about the same as far as AF and IS/VR and body size go. The Sony will give you about 3x the fps, and much better 4K video and slow motion capabilities, the least weight and length by about 1.5x - 3x. The Nikon D7200 + either of the lens setups mentioned will give slightly better Dynamic Range and battery life.
Finally, you will really need to hold/point/shoot all of the options mentioned to see if the ergonomics suit, and what the balance, point ability, start up times, and speed of acquisition are like.
Given you mostly want record shots - if you're doing that in good light, and moving around quite a bit, then why not save on the weight and expense of the DSLR setup and get the Sony RX-10 IV? - I'm sure it will show a tangible improvement over your current rig. Ultimately you will have to decide which compromise suits you best. Good luck with whichever way you go.
Chosun :gh: