[biz-engineer]

The reasons and the evidence that Normhead presented now make it clear to me that ....for my needs...the TC is the way to go ...and if I ever do spring for the 300 the TC will just be an additional bonus.

It is a bit quick to conclude that TC is the way to go. With more than one TC stacked, lens camera body communication is lost, depending on the TCs used, AF does not work, + wrong focal length implies that SR does not work properly. We should not take one specific case of the bird feeders to prove that 200mm is adequate for birding, as there are many other cases where 200mm and stacked TC aren't the best choice at all.

[Lowell Goudge]

As someone who does a lot of birding, and who has played around with a ton of options, I have settled on 3 different ones for very different reasons, at least for the moment. My ultimate goal is a sigma 500/4.5 or the DA560/5.6 and some form of TC, but after 35 years of shooting, birth film a d digital, here is where I have gotten to.

For stake outs, and shooting from fixed locations, ultra low light (on a tripod) I have a tamron SP 200-500/5.6 on a gimbal mount. This has a KA adaptall mount, so I can also shoot PTTL flash and add a TC to get to 750 mm. The Tammy can also accept the sigma and Pentax TCs that have protruding front elements which are specifically designed for ultra long zooms.

For hiking in the woods, and most general shooting (usually birding while dog walking) I will shoot with a sigma APO 70-200/2.8 EX ( this is an early version non DG and non macro) it is generally regarded as one of the sharpest sigmas especially wide open at the long end, and works great with the 1.4 and 2x sigma APO EX teleconverters . It gives it he option of shooting at F2.8 for close things, or depending on TCs F4 or F5.6. I have also stacked both sigma TCs, (note here, the 1.4x must go behind the 2x they can't be stacked in the other order due to protruding front elements) but my K10at the time had a hard dime getting focus lock.

If I want reach without weight (the sigma plus 2x is about 2 kilos). I take a K300/4 with the 1.7x AF adaptor. What's interesting is the K300/4 is actually lighter than the DA300/4. It is a very capable pairing and light weight at just over 1.1 kilos (btw I forgot the Tammy 200-500/5.6 weighs in at 3 kilos, not counting another 6 kilos for the tripod and gimbal head.)

Overall the sigma plus TCs is most versatile, and for times when I have the big Tammy out I would use the sigma with or without TCs as a light weight shorter companion, just in case there is something else of interest comes by while focused with the big lens on the principle subject.

If I really need length, I also have a 1000mm mirror��

The point is, for most wildlife 200 on its own is not enough for close ups, but works fine for either really bit birds (perhaps herons, which you can get close to, but not Hawks which are almost unapproachable), 200 mm will give good behavioural shots of groups of birds but not individual shots of most birds, although I have posted a shot of a hawk, shot with an FA 28-105mm because it wa more pre-occupied with the mouse it was eating��

[AmaZing]

Thanks @VoiceOfReason, @cdurfor, @shaolen, @biz-engineer, @Venom3300, @bassek, @D1N0, @Driline, @goatsNDonkey.

Special thanks to @normhead, @skyclad666, @LowellGoudge. That was some very SOLID piece of practical advice.

Took me a while to digest all that information and even longer to relook at the type of bird photography I actually do vs the equipment I am willing to invest at the moment and CARRY in the field. Wonder if it is not such a bad idea to hire a caddy / sherpa to help with the heavy lenses...!

Heart says: buy the biggest lens I can convince myself (and wife :-) ) to buy. Brain asks: will you actually take it out for a few hours of low-planning outings?

Here is what I am currently gravitating towards: DA* 200mm (but the new updated one that is due for release) with TC 1.4x. Probably also ƒ1.7x AF adapter. Thanks @normhead.
Reason:
1. Most of my birding happens during either early morning sojourns into the countryside or on family outings. Will enjoy a lighter setup a lot more. Besides a 200mm may be just right for occasional wildlife safaris / treks. Even if I fall a little short on this setup, this FL will not be a total waste as it is still usable for other activities. Perhaps go longer FL later. @LowellGoudge has a dream setup!
2. Agree with @skyclad666: I was constantly shooting at 200mm on my current 55-200mm consumer Nikon setup. So the zoom is something that I may not miss direly. The TC should take care of some of the limited reach of 200mm.
3. Relying on the crop-factor and the possibility of cropping a 24MP image to get tighter final pictures.

A couple of questions:
1. Is the SDM motor in the DA* 200mm and 300mm lenses from before or after the time Pentax acknowledged and fixed the SDM issue?
2. Where can I get some good information on strengths / limitations of ƒ1.7x AF adapter on (say) DA* 200. Specifically what will TC 1.4x be able to achieve that this converter will not? A couple of lines on focus limiting purpose (on this lens) and general mechanism also please…

[Venom3300]

The DA* 200 and 300 never suffered from SDM issues the way that the 16-50 and 50-135 do. They are also a bit faster to focus than those two which keads me to believe its an improved design.

There have been SDM failures in the 200 and 300, but rarely.

[zapp]

Sold my DA* 2.8200 for the DFA* 2.8/70-200. I like the perfomance of the zoom much better. Zoom is much heavier and bigger and has the advantage of being a zoom. AF and IQ is in my opinion much better than for the older prime.
My DA* 300 was a pain to use with Tamron 1.4TC. Pentax 1.4TC worked better, but was not convincing. IQ dropped too much and AF required lots of light.

Differenes in price and weight between zooms and primes are extreme here. The DA* 300 is a skinny bitch compared to the bulldozer size of the 70-200. You get used to everything, but do not unterstimate the difference. 150-450 may become interesting on FF for me as it cover the APS-C reach of the 300. Beng a zoom you do not need to mount/dismount the lens to change focal length. For walk around 70-200 and 150-450 are seriously big.
200/300 have no focus limited, share the same lens hood ...

[Driline]

The DA* 300 is a skinny bitch compared to the bulldozer size of the 70-200.

LOL. Well said. I've got an F*300 (possibly the best lens Pentax has ever made IMHO) and the DA*200. I've contemplated selling them for the new D FA 70-200, but man the size of that beast gives me nightmares

So this evening I'm heading out to shoot a demolition derby so I'll be taking both my DA*50-135 and DA*200. The D FA 70-200 could have replaced them both, but at $1,200 for the two lenses I've still got an extra $600 in my pocket. That still doesn't mean I wouldn't miss the D FA 70-200. I'd still like to purchase one

Here is what I am currently gravitating towards: DA* 200mm (but the new updated one that is due for release)

That's probably at least 2 years out "IF" they decide to make it. My guess is the price will also be upwards of $1,200 or more. I bought my DA*200 for $650 used from Adorama with warranty. On the upside it does give you plenty of time to save your pennies.