I use an r5 and the rf 100-500 is a great lens. It's very versatile and got great performance.

I've taken it on african safari, treks into the amazon jungle, and out whale watching on the ocean. The range of the zoom gives you that flexibility, and the quality means you can crop in if you need a bit of extra reach. I've been looking at get the 200-800 too but I'm struggling to fully justify it, I just can't see it replacing my 100-500 when I'm travelling about and it's not worth getting just for domestic trips.

I shoot with the R7 and the R5. I've owned both the 200-800 and the 100-500 (and the 100-400). I strongly prefer the 100-500 for all wildlife. The 200-800 is useful if you need tiny birds from a distance but I think you'd be happier with the 100-400 (very light weight and inexpensive) or 100-500. I shoot wildlife exclusively (birds and non-birds). If you want to see sample images with all 3 lenses used on the r7 and r5 feel free to check out "Kenzo Pan" on flickr. You can see the details of what gear was used and the settings on each image. I find examples with lots of detail are the best thing to help me choose a new lens.

This is an image I took with the 100-400 (by far the cheapest and lightest option).

https://preview.redd.it/22umhvpuogse1.jpeg?width=3570&format=pjpg&auto=webp&s=57ae30a8ed36f59821d59f8d953e4c271fb97a02

What is the sigma 100-400 not doing for you? I have the 100-500 and use it constantly with my R5ii… I’ve considered the 200-800 but that is a chonky lens and I’m not sure I’d want to hike with it…. It’s 50% heavier than the 100-500 (3lbs vs 4.5lbs) and 50% longer when neither is extended (8” vs 12”)… that doesn’t really matter with a tripod in a bird blind… but it would 3 miles into carrying it around on a strap … heck my camera bag isn’t large enough to fit the 200-800. If you’re not a serious birder AND you’re using an APS-C body then the 100-500 seems the clear choice.

My targets are definitely not birds, although I do like to try and get snaps when I encounter various larger birds (mainly harris' and red-tailed hawks around here.) Sadly, even those seem to leave me wanting for longer reach so I rarely bother. In fairness, I'm mostly whining about the in-flight shots, which are a skillset I definitely haven't developed much. Stationary shots are still great.

Everything else is smaller critters, including small lizards, gila monsters, snakes, etc. For that, the 100-500 has been utterly AWESOME (on r5m1 and r5m2 for the body.) Gonna be a cold day in hell before I let that lens go.

https://preview.redd.it/iuug5jc5uhse1.jpeg?width=3840&format=pjpg&auto=webp&s=8c25deee15453fd7d5c65bf0107f413a7b2bdfd4

You mention having a Sigma 100-400mm, how's that lens working for you and what do you want to gain from replacing it?

Usually the RF 100-500 L is preferred over the 200-800 on APS-C for wildlife photography, especially so if you aren't mostly shooting small birds.

Good "pro" gear for wildlife costs hella lot, since you need long lenses. For wildlife its good to have at least 600mm full frame equivalent lens, but you might want to use crop sensor camera, so a zoom lens with 400 to 600mm max focal length should be good. However you might be able to get closer to not require that long focal length with your backyard animals. But for "serious" wildlife stuff, you should have something like 600 to 1000mm+ (full frame equivalent) lens.

Using crop sensor cameras makes you get those mm's easier, or equivalent for those on full frame. You can use tele converters, but they make you lose image quality, lose light power(if you lens is not fast, it will be way dim for many uses) and might cause problems with autofocus.

Also because long lenses with quality cost shit tons of money, getting a crop sensor camera and a long lens is a better idea, than playing with teleconverters, or full frame cameras.

Canon 1d series with its 1.3x crop factor is also good, and they have very nice autofocus, but they tend to be a bit outdated or still very expensive(depending on generation). Also you cant use 1.6x crop lenses with them, which takes away many budged friendly lenses.

Leica SL2 w 90-280

Consider the Nikon D 500 camera. It is designed for professional reportage, including wildlife photography. The camera is very light in the hands. For a start you can equip it with a 75-300 lens.

This will be one of those times where the lens will set you back as much if not more than the camera body

Without knowing your budget, I'd say the Canon R10 + the RF 100-400 is a very good starter combo for wildlife photography. Gives you eye-tracking AF and 640mm effective focal length in an incredibly small and light package for $1600 total.

Save up for the 70-200 f2.8 and get sneaky like a bow hunter to make up for the lack of reach.

I'd recommend saving more and getting the sony 200-600mm Failing that, a sigma or tamron 150-600mm

you're basically looking for something with the long focal length and wide aperture (so you can use higher shutter speeds). If you're okay with 3rd party gear, theres the Tamron 70-300. First party, theres the used Sony 70-300, or if you want new, mby the Sony 70-350mm

Sigma 150-600mm is very popular.

Going to public parks and even a local zoo is a good way to practice your shots. Unfortunately the 70-180 might be a little short for what you’ll ultimately need, but definitely use what you have and just go out and practice.

Also, local photography groups on Facebook often have great locations to find some good local wildlife that you might not see just walking around.

Grab a camera and whatever lens you have. Start taking photos. Check out YouTube of videos of wildlife photographers (non-sponsored preferably), not to ape their style but for general tips specific to wildlife photography. After awhile you'll start to realize what you need lens wise (the 70-180 is going to be a bit too short but not impossible - it is the range I started with and how I figured out the reach I needed for the subjects I wanted to shoot).

. . .also do not buy a 15K lens as a "start" into wildlife photography.

Typically 400mm is the shortest recommended FL. It's definitely possible with shorter FLs. But longer is definitely better. Fortunately we live in the golden age of good relatively affordable long glass. You need to develop skills besides just camera skills.

This article sums it up best. https://www.zsystemuser.com/nikon-z-system-news-and/lets-play-the-telephoto.html

Best lens is a 600 f4 Tc.

How you get started, go out and shoot wildlife. Then keep doing it.

Steve Perry has a lot of good videos.

There is also The Tamron 150-500 for Fuji now. Also worth looking at.
Personally i like it more than the 100-400 for example.

There is not much choice with Fuji. You do not mention budget, so the most natural step up from your current lens is the 150-600. Personally I would not take the adapter route, unless it was for being able to use a significantly better lens, like a 600/4. Such lenses are so much more expensive than anything I have that if I was crazy enough to consider them I would probably also change the body with a good FF system. Equally, I would consider the teleconverter only to go longer where a longer alternative does not exist.

Not fuji

XF 150-600 mm

XF150-600 or the Tamron 150-500. I got the Tamron and shoot 90%Wildlife.

For Sony APS-C the best wildlife lens is the Sony 70-350 by a country mile, considering everything: weight, price, focal length and image quality.

I'd say that's the best lens of the whole sony APS-C system and maybe the best wildlife lens for crop sensor cameras.

So I'd save for that one. You may find it cheaper used or if you wait for one of the sales. It was on sale last UK amazon prime day, you can check the price history with the camelcamel website.

Could get a cheap old Ef mount 300mm but they kinda suck ass

Maybe save up some more and get a used Sony 70-350 ?

My budget is around 500$.

Good luck with that.

100-400 is the best all rounder but will cost you. Tamron 50-400 is a solid runner up. Then if you can handle the weight the 180-600 will get you some more reach.

But for hiking I would get the 50-400.

You might look at the 28-400. It’s gotten nice reviews and looks pretty light

Consider the tamron 50-400 if you are already willing to take a bigger lens with you. On a modern Z body it does wonders, I enjoy using it on my Zf. I feel that it's also not that dim to work against you in action shots.

The 28-400 is a very versatile, lightweight and less expensive lens, if you can live with F8 at the longer end. I use it for daytime sports(soccer) over my 35-150, 70-200 or 180-600 lenses. Nothing beats the 70-200 for quality pics, but it is bigger, heavier, less versatile and more $$$ for sure

100-400 is going for 1480$ on photomarket

Sigma and Tamron 150-600mm are the two “budget” wildlife lenses commonly used, will give you a lot more reach than you have now. Keep in mind there’s never “enough” when it comes to wildife, but 600mm is pretty good.

The tamron is much lighter, but the sigma is a tad sharper. Both are around $1000-1400 depending what version you get and whether its used etc, if it were me i’d get the tamron 150-600 g2

Anything with 500mm or more in a premium lens you’re looking at $10k easily, once you push beyond 300mm the prices skyrocket especially if you want sharpness and good aperture.

150-600 from Sigma or Tamron are the popular choices that other people have mentioned.

But there's other options if you don't exactly need that much reach. Your 18-250 is something with tons of zoom, but not very sharp. If you need the same zoom, but not as blurry, there's the excelllent 55-250 IS STM, which is much cheaper than other optiosn and still fairly sharp, plus a lot more portable.

The 70-300 is a bit bigger than the 55-250, but still portable compaared to the 55-250. Very sharp and the USM II has very good AF.

Then you have Canon's 100-400. Very good lens, lighter than the 150-600, but it starts to increase in price. Sigma has a 100-400 which is cheaper, but not as sharp.

You can also use a 1.4x adapter that gives you more reach and still keeps quality (don't bother with the 2x).

I also have the Sigma 150-600 and it does a fair job for birds and wildlife. You should be able to find it or the Tamron equivalent used to get started.

When I first got into photography, I though I'd want more reach. Now that I've done it for a while, I've found myself investing more in wide angle or macro lenses. So what you think you want to do now may change as you get more experience, so unless you're certain you want to spend a long time waiting for wildlife and have infinite patience, you might find yourself drawn to other aspects of photography. Since you're new, I'd recommend avoid investing a lot in a telephoto lens now until you have a better idea that it's where your photographic passion is, as they are the most expensive lenses (and the hardest to lug around).

That being said, and I may get into trouble for saying this, another option is to stick with your 18-250mm for a while (or get another relatively inexpensive telephoto like the 70-300mm that's likely a little sharper and has slightly more reach) and try software like Topaz Gigapixel to enlarge your photos. You can get it on sale much cheaper than a new lens would cost, and I find that it does a good job at enlarging the details on animals. I only started playing with it recently, but I've been very impressed. I've also tried ON1 Resize. AI in photography is gaining ground every day, and enthusiasts may not reasonably need to invest in extra heavy, expensive telephoto lens to get good enough results for small/medium prints.

Another option is to upgrade your body so you have a larger sensor, letting you crop the image more without losing resolution.

I bought myself a Sigma 150-600 F5.3-6.0 for around 650€ I love it very much

Just grab a sigma 150-600, used u can get them at a decent price. Also for what you get they are actually fairly cheap.