Originally posted by CarlJF Maybe I'm missing something, but what exactly is so wrong with the Pentax 560mm that it could not be considered a viable alternative to a 600/f4 ? Okay, I understand it's one stop slower, but it's not such a big drawback on a camera such as the K-1. Raise the ISO one stop, and you're still as good if not better than the f4 on a Canon body. As for FL, the 40mm difference doesn't make much difference in practice. So, what more can be achieved with a 600/f4 that cannot be done with the 560mm 5.6 to the point of making it unusable for that purpose, making a 600/f4 the only way to go ? I'm asking, because I really can't see... Why wait for an hypothetical 600/f4 when a 560/5.6 is available right now ? If the reach of a 600mm is really needed, why not just get the 560 ?
The DA560 is a good idea because it corresponds very well to what's needed for static wildlife subjects. Lots of people say that the DA560 is too long, well, it not that long it's like any long lens like the 400 f2.8, 500 f4 and 600 f4, it's not the kind of lens for walking about, it's the kind of lens you mount on a gimbal anyway, and f5.6 3kg is about perfect for static subjects. But, I consider the DA560 as a failure because its price is too high. Since it is a telescope design with less glass elements and more flare, the lens should not be price higher than a telescope of the same quality, e.g $2000, but Ricoh sells it $4000. For $4K you get a Sigma 500 f4 and you can add a TC on it. Basically, people who want the long prime on their Pentax camera take the Sigma 500 f4.5, the DA560 not being competitive on price.
---------- Post added 27-04-17 at 20:48 ----------
Originally posted by redpit So why I haven't bought the DA 560 and why I would buy, for example, the new Sigma 500/4 the same day that would hit the market in K mount: - It's a DA lens that vignettes a lot until F8 - It's too long to carry around and needs special-seperate bag - It's slower than other primes at its price tag (though this is not a deal breaker for me) - It can only handle the 1.4X TC and that decreases its versatility - Its minimal focus distance is too long at 5.6meters (bad for birding) - Its DC motor is quite fast but not HSM fast (again not a deal breaker) - It's not a * star len and you only buy once that kind of lenses. If it were a star lens CA and FR performance would be greater i believe.
Too expensive versus what you can get from Sigma.