[Nicolas06]

I've got a Sigma 150-500 in K mount. I'm pleased with it's performance. Will an extra 100mm make a significant difference ?

That's the funny thing! 600mm vs 500mm is like 60mm vs 50mm. That's nothing objectively. If the photo look great at 600mm it will look great at 500mm maybe even a bit better sometime if the framing is more appropriate. At worst you can reframe manually to 600mm. This cropping a 24MP image to 16MP.

Guys going FF will get much more framing difference their 600mm not getting more 400mm on APSC.

Guys using primes don't take in their bag dozen lenses to cover every possible focal length and their photos don't look any worse. It is even admitted it help improve your skills and get you better photos.

The whole argument is 600mm is more than 500mm, just a tiny bit but it can convince some they need the gear. While it make sense to choose the 150-600 if you have no equivalent tele already (nothing longer than a 450 say) and if you are in the way to choose a system this can be an argument if you mostly shoot this long, this is really a detail in what it will allow to do more compared to existing 500mm.

Anyway theses lenses are already stretching the limits, they are heavy and so-so quality at the long end. It is OK, but not really better than what a 18-55 does at 55mm.

There also the problem of speed, high isos, that theses lenses prefer f/8 than f/5.6 and finally of atmospheric fog that limit what you can hope to get in practice.

While for sure 600mm will add some little convenience and reach the guy that did manage to be more near to the subject and frame it at 300mm will be the guy with the best shoot and also best optical quality by far. More it could do that with a 300mm prime far better at f/4 than the zoom is at f/8.

The real upgrade when you have already a 150-500 or 50-500 is optical stabilizer or going for better grade gear like a 200-400 + TC, a 400mm prime + TC or in Pentax the DA560.

Already DA300 + TC will be signicantly better than a 150-500 at 600mm (420mm + crop) and will manage the comparison with 250-600 at 600mm while being far better 300-500mm range than the other 2.

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Last edited by Nicolas06; 01-03-2015 at 03:27 AM.

[lesmore49]

Well yes, 20% more magnification, faster focusing and weather sealing. It'll probably make you feel you're using a Pentax. Just probably.

Do you have a Sigma 150-500 ? I ask because it's really quite a good lens from just about any perspective.

Weather sealing...I usually don't take pix in driving rain or blizzards, so I think I'll be fine.

The other thing is that with a large, heavy telephoto...you're usually going for a faster shutter speed....yes even with either the Sigma OS or the Pentax SR...you still need fast shutter speeds....BTW...use only one, not both systems. I try to use at least over 1/500th of a second....more like 1/1000th to be sure. A larger, heavier lens like a 150-600...more shutter speed and outdoors...cloudy weather, etc....can't always accommodate.

Heavier and longer focal length (ie; 150-600) is fine....but like everything else in this world...there get's to be a point where it's enough. Even though I'm a big guy, I find the Sigma 150-500 about my limit...weight and size wise.... for carrying around and using hand held. With this lens, I'm usually wandering down some forest path and every bit of weight...magnifies...as time goes by.

I prefer hand held due to faster response if I see a fast moving subject.

For me, 500mm is enough and it seemed to be enough for most others.... till Tamron upped the ante to 600mm...then Sigma met Tamron with their own 150-600. So my question is...is having 100mm more about the guy who wants the biggest lens on the block...or about actual usability ?

I find with maximum of 500mm at my disposal, I can get close enough to the wildlife...ie; owls, deer, etc...or drag racing cars on the track...that I need.

I'm not sure what you mean by using a 150-600 will make me feel like I'm using a Pentax ? The 150-500 already does...the AF system is quiet, smooth, relatively fast. Sigmas zoom control works in the opposite direction to my Pentax lenses...but no big deal for me.