The other day I was photographing my workplace buildings using Q7 (12Mp 1/1.7 inch sensor) with a small 250mm f/4.5 telescope. When I focused on a building 2km (1.25 miles) away from me, another building 4km (2.5 miles) away was reasonably in focus due to large depth of field and that was satisfactory to me and a few others.
Anyway, some days later, I remembered that another colleague has Nikon P900, which is a super zoom camera with 18Mp 1/2.3 inch sensor. I wondered how it performs in a super tele application and borrowed it to make a comparison with Q7.
Left is Q7, right is P900, both OOC jpeg. Both were shot on the same day, only minutes apart, both on the same tripod. I first shot with P900 and it was brighter, but the difference is not as drastic as you might think from the pictures. I zooomed in with P900 to get roughly the same angle of view as Q7 and ended up using 214mm f/6.3 (wide open) but it seems like I overshot a bit.
I got similar DOF and nice details in both, you can even see a crow on top of liquid nitrogen tower. Resolution is better on Q7 probably due to better lens (2nd picture is a 1:1 crop, see e.g. three small metal poles at the right edge of the roof that's almost completely invisible on P900) but that's to be expected. WB is very different but that's a matter of personal taste. In other words, no surprise.
But I'm REALLY impressed by P900. The lens is pretty good as an all-in-one solution, SR is better than Q7, less weight than Q7+telescope (my telescope is
tiny but still about a foot long incl. Pentax PK adapter, and all metal), usable EVF that doesn't make me sick, and a vari-angle LCD. I'm not sure if AF is good enough for proverbial drunk biker, but I haven't spotted any such biker here fortunately, and it feels snappier than Q7 and, say, 06 lens. Also, zoom is an awesome thing for the field of view equivalent of 1000+mm on FF, fixed focal length like telescopes are really hard to point to where you want to even though I'm reasonably good at it.
I won't trade my Q7 for P900. There are many reasons, the most important is that I like flexibility of interchangeable lens. Ultra wide, macro, super tele, anything inbetween, pretty much for any purpose I have a lens (or lenses) for that. But I have to say Nikon struck a very good balance between the feature set (lens quality and convenience) and price.