There ins't anything... and it's not necessary to have anything. The problem is, better than the 55-300. If you look at the 55-300 images on the forum, you understand that it is the premium less than DA* lens. None of the 70-300, 100-300 type lenses match it, especially in the long end. Hate to keep dragging this out.. second time in two days
Quote: From my old "what lens" post which I can no longer find.... one is a DA*60-250 one is the Sigma 18-250 is one really worth twice the money. My buddy Jerry who was standing beside us shooting a Canona with a 200mm prime has almost this exact same image in his store at 8x10 and as far as I know has sold about 20 of them. I seriously doubt he would have sold fewer if they'd been taken with the 18-250. When people go on about the need to be using the sharpest or the fastest or the whatever-ist, way too often they are talking theory, not practical experience.
Too often people quibble over things that don't matter. That's what living in your own mind will do. You start imagining all these scenarios where you need this or that lens, when in many cases, you're better off with a superzoom that lets you get the shot. People talk about convenience as if it doesn't really matter. Well convenience doesn't matter unless you miss a shot because of a lens change, and then it's the only thing that matters. Superior IQ does count for squat if you're missing images trying to achieve it. Not doing a lot of lens changes saves time, and saving time gets you to different locations faster. Using primes, you may not even get to a lot of places superzoom users get to, because they spend more time scouting locations and less time fiddling with their camera bags. There is a lot in these lens discussions that comes directly from a lack of real world shooting experience and the the lack of printing experience so they understand exactly what they need for what size print.
Eastern Red Wolf DA*60-250-- Sigma 18-250 - which is which? An 18-135 image would have fallen right between these two images in IQ, but what exactly would that count for? Both are useable. How could it matter what lens I had on the camera if I don't really prefer one image over the other? I'm willing to bet the image would have been just as printable, saleable and enjoyable taken with my old Vivitar 135 ƒ2.8, arguably the worst lens in my collection. So what is everyone going on about?
The appeal of these images is not even influenced by the difference between 2100 lw/ph and 1700 lw/ph on a test chart. Because these images were not taken on a sturdy tripod with a two second delay in a studio setting with no wind etc., there is simply no discernible difference even pixel peeping.
The first question that comes to mind for me when people are going on about really sharp lenses is, 'Show me an image that you've taken that would have benefitted from using a sharper lens?" ( Hint, if you aren't shooting on a tripod, using the sharpest lens available isn't even going to improve your work one bit. Not shooting on a tripod, you may as well use a superzoom., using a super sharp lens won't increase your IQ even a little bit.) ) People need to do that, before they start proclaiming to the world that they have to have the sharpest, fastest, whatever-ist lens.
So here you have two lenses one much sharper than the other, but for which it's really hard to see any practical difference in the images, and you're saying that Pentax needs to squeeze another lens, at maybe 1900w/ph between the two when you already can't tell the difference in a lot of images. I think that's why people are a little negative about your post.
You are asking for something that is totally un-necessary. The advantage to the 60-250 is you can put the HD DA 1.4 TC on it and get a very good 350mm lens that shoots @ ƒ5.6, more than what you want.
The idea that there could be an intermediate lens between that and the 55-300 which is better quality than my Sigma 18-250, just doesn't make a lot of sense. Long glass is expensive... really good long glass is even more expensive. That's just reality. It's a hard reality, and many of us have spent hours wringing our hands and gnashing our teeth over it, but, there is not easy solution, either for shooters, or manufacturers. Part of the problem is you aren't appreciating how good the 55-300 is. The second part is if 250 won't do and you have to have 300, there's just not that much different. You probably need longer and are just trying to make do. The lenses you need are there. The DA* 60-250 and DA* 300 coupled with the 1.4 TC. I think you're just going through what all of us go through when we realize we want to shoot longer glass, and start grappling with the prices good long glass goes for.
If you aren't planning to use a TC the big difference between the 55-300 and the DA* s is the constant ƒ4 of the DA*s. The 55-300 is ƒ5.8. AN intermediate lens would have to be between ƒ4 and ƒ 5.8, say ƒ5. You need to be selling a lot of lenses before you start breaking up your lens offerings into half stops to fill every price point.