Canon 200mm f/2.8 L II USM vs Sigma 70-200mm F2.8 EX APO DG OS or something else?

Question

I'm looking for replacement of my Canon EF-S 55-250mm f/4-5.6 IS STM. Camera is Canon EOS 700D.

Requirements:

• amateur photograph, especially nature and birds, mostly walking rarely hiding,
• focal length is enough, most of the time using 250mm,
• I found many situations when lens was too dark,
• ex. bird sitting inside tree behind branches, dummy morning, cloudy weather and photographing in bushes,
• budget up to 500$ and I'm in Poland,

Candidates:

• Canon 200mm f/2.8 L II USM
• Sigma 70-200mm F2.8 EX APO DG OS
• maybe Tamron 70-200 f/2.8 Di
• maybe Canon EF 70-200mm f/4.0 L USM

Doubts:

• as most of the time I use max zoom of 250mm maybe I should buy prime lens? Will it give much better results than ex. Sigma zoom of similar price?
• do I really need f2.8? Maybe f/4 would be just fine? (Often object fills about 50% of frame),
• is image stabilization compulsory? (Very often I use quick shutter speed because of "quick objects" I photograph),
• will Canon @ 200mm f4 but luxury take better photos than 200mm f5.6 but my actual one?

I'm not very experienced photographer and after reading and watching dozen reviews I feel like all above are great lenses and suitable for me. I will be thankful for some advices!

Answer 1

I currently have the Tamron 70–200mm f/2.8 and it is a powerhouse of a lens that is very versatile. The f/2.8 will allow you to achieve a noticeably better bokeh than the f/4 and gives you the ability to lower your ISO in comparison to a f/4 or a f/5.6. It is a durable lens and in conjunction with a 1.4x or 2.0x teleconverter it will allow you to reach even closer to the subject. The reason I would choose this over a 200mm prime is because you have the ability to zoom out all the way to 70mm while keeping the f/2.8. It will allow you to play around with your composition of the subject and allow space for cropping should you need to.

Answer 2

As a former long time Canon 700D user that did wildlife and amateur sport photography with some of the lenses that you listed as your options, I recommend you go with the 200mm f/2.8. It is a prime lens, it's much sharper than zoom lenses, and also lets in more light due to the f/2.8 aperture. I used the same combo (700D + Canon 200mm f/2.8 + 1.4x teleconverter) for most amateur soccer games I photographed and also managed to get some amazing bird and deer shots with nice background separation.

I also had the opportunity to test the 70-200 f/4. Although it has amazing image quality, the f/4 aperture will force you to increase your ISO, and the 700D isn't the best at high ISOs.

On your doubts:

1. go with the prime lens so you keep better image quality
2. with birds definitely go with the f/2.8 version on that body
3. image stabilization at high shutter speeds is unnecessary, and sometimes has the opposite effect, but still the f/2.8 will allow you to shoot at higher speeds.

But again this is very subjective since I can only recommend you from my experiences.