[Skog]

Hello.
I am currently looking for a DA or FA * 300mm prime to use for birds and wildlife. I currently own the DA 55-300mm, and it's ok for most. But I really want to go all out and get the added sharpness of a prime lense.

And the second major point is that I want the ability to add a teleconverter for that extra reach (since the FA * 400mm is nowhere to be found ).

I want to retain as much sharpness and detail as possible, and I want to have AF.
My question then is what teleconverters do I have to choose from?

[Adam]

If you're looking for sharpness, you're very very limited. I recommend the SMC Pentax A teleconverter 1.4x-L combined with any compatible lens- you'll get fantastic results.

I've tested it with the 300/2.8 and K 500/4.5 with remarkable results. Run a forum search for my posts and the keyword '700mm' to see some test shots I can't link you at the moment as I'm on the Blackberry.

[Adam]

No AF for the above combinations, though For that, I'd recommend the sharpest lens I've ever used, the FA* 300/2.8. It's one of the few lenses to carry a solid ten in the lens reviews

A raw, blown-up image taken with this lens is quite likely to be comparable to one taken with a longer lens, or a lens with a teleconverter.

[northcoastgreg]

A 300 prime will get you sharper results than the 55-300, which is a bit soft at 300. Getting a decent teleconverter to work with it can be a challenge: I've done a bit of research on the subject and can't say I've found anything either readily available or compelling in terms of performance. The Pentax 1.4x-L won't work with the DA* 300 and is hard to find (though it seems to be the best IQ wise). The Pentax Pentax-F 1.7X is another compelling alternative: it is well thought of and will work with just about any lens you use it, but it is also hard to find and can sell for as much as $500 on ebay. I've also heard good things about the Tamron 1.4x as well: decent IQ, autofocus works, etc., but it's also hard to find (Tamron no longer produces one for Pentax). Still in production, but not as well thought of, are teleconverters from Promaster and Kenko. The Kenko, from what I can gather, does not to autofocus with SDM lenses, and the Promaster struggles to autofocus.

[Lowell Goudge]

you can also consider perhaps a used 300F4 to go with the 1.7x AF TC. I use an SMC300F4, but if you get an SMC-A 300F4 you get allthe auto exposure features as well.

See the attached post showing what the SMC 300 F4 can do when used with the SMC-F 1.7x AF TC

https://www.pentaxforums.com/forums/general-photography/100077-question-bird-...ml#post1030308

Also see the attached shots for my other long combo the sigma APO 70-200 F2.8 and 2x TC





there are lots of options

[imtheguy]

I use my DA*300/4 every day and have both the Tammy 1.4x MC4 (supports SDM) and the Pentax AF 1.7x TCs. After thousands of shots I now use the 1.7x or nothing since the additional reach of the 1.4x barely compensates for the slight drop in IQ and the bigger drop in sure focusing as its tendancy to hunt or quit. Cropping from the 300mm often works better, not always though, than using the 1.4x. But I am always using it handheld and in the hunt for moving targets. When using a tripod and reach is the biggest factor then the Tammy is more useful to me.

The Pentax AF 1.7x however always beats out a crop from just the lens alone plus for BIFs, it gives you a built in focus limiter that gives me more keepers than using just the lens alone. I also use the 1.7x with my Tammy 90/2.8 macro lens to give me a much easier to work with extended macro than extension rings.

I don't find the Tammy to be a bad TC but the Pentax is so much more useful for only 1/2 stop penalty.

[Adam]

I've found the F 1.7x AF converter to be decent, but obviously not as good as the L converter. It has trouble working on slower lenses, and makes the AF hunt a little more than normal before locking on. Obviously this isn't much of a problem on F2.8 lenses, but it's quite noticeable on F4's IMO. On F5.6 and below, the AF may as well be disabled.

Here are my sample shots from the other thread.

K10D + K 500mm/4.5 with 1.4x-L converter, F8, 1/250s

original


100% crop

Adam
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[Lowell Goudge]

I've found the F 1.7x AF converter to be decent, but obviously not as good as the L converter. It has trouble working on slower lenses, and makes the AF hunt a little more than normal before locking on. Obviously this isn't much of a problem on F2.8 lenses, but it's quite noticeable on F4's IMO. On F5.6 and below, the AF may as well be disabled.

I never found it an issue on an F4 lens, but I agree, on F5.6 there is no point, but consider that is equal to F9.5 or something

[imtheguy]

I too have both the 1.4x-L and the 2x-L but since they are unable to fit many modern lenses (like the da*300/4) and do not have the AF feature, they get used far less than the AF 1.7x.

Skog, if you end up with the da*300 then the "L" TCs can not be used.

[JeffJS]

DA*300mm + f1.7x AF



Once you get use to using it, it is actually a very fast (focusing) combo. Get the lens focus close and the converter snaps it right into place. Better than a 400mm+ dedicated lens? Probably not but good enough for me.


1400

[Canada_Rockies]

If you're looking for sharpness, you're very very limited. I recommend the SMC Pentax A teleconverter 1.4x-L combined with any compatible lens- you'll get fantastic results.

I've tested it with the 300/2.8 and K 500/4.5 with remarkable results. Run a forum search for my posts and the keyword '700mm' to see some test shots I can't link you at the moment as I'm on the Blackberry.

It works moderately well with the M 400/5.6 as well. I'm going to try the F 1.7X AF on the M400 and see how it compares. I ran across a pair of Harlequin ducks not far from here, and when we have decent light in the afternoon, I'll give both a stab. I have access only to the West side of a North/South river, hence the afternoon sun. I took some snaps Saturday, but did not have the 400 with me, it was a recreational hike. I fitted the 1.7 to the DA* 50-135 and got some nice shots, but colours are a bit dull (it started to spit snow an hour later) and the birds are quite small in the frame.

[Skog]

Thank you for all your answers

So what I get from this, is that if I want AF, the 1,7 pentax is my only option. Am I right? I really need some AF atleast, since the K-x is not ideal for manual focus, and I use glasses, so it's a bit difficult sometimes. Not to mention in dead slow .


Too bad all the glass I want is no longer beeing made, and rare/super rare.

The DA * 300 + 1,7 TC seems the best choise so far. That would give me a 510mm f7,1 right? Good for some really good light situations I guess. But I can just use the 300mm alone in those days, and just accept that some will be out of reach

Is there anything I need to look for when buying a used 1,7 tc? Any bad copies ect.

[dadipentak]

The DA * 300 + 1,7 TC seems the best choice so far.

It's a really very good combination: 510mm FL in a very portable package. Use at least a monopod (tripod for optimal results.) Get used to shooting MF, though--it's often the case with wildlife that AF will be confused about what it's supposed to focus on because of branches, brambles and weeds.

Is there anything I need to look for when buying a used 1,7 tc? Any bad copies ect.

Surprisingly, I've never heard of a bad one. Apparently, though it was out of production fore years new ones have (rather mysteriously) appeared on the market this past year.

[Lowell Goudge]

Thank you for all your answers

So what I get from this, is that if I want AF, the 1,7 pentax is my only option. Am I right? I really need some AF atleast, since the K-x is not ideal for manual focus, and I use glasses, so it's a bit difficult sometimes. Not to mention in dead slow .

only if you are predisposed to get the DA300

Too bad all the glass I want is no longer beeing made, and rare/super rare.

it is a question of patience not just the availability

The DA * 300 + 1,7 TC seems the best choise so far. That would give me a 510mm f7,1 right? Good for some really good light situations I guess.

No not just good light conditions. look at the link I posted, one shot with K7 at ISO 800 and 1/40th of a second, I would not call it good light, the other shot used a flash to freeze the image, again not good light. It can work in all light, achieve Af onan F4 lens, your technique will be the limit not the lens, the TC or the light.

But I can just use the 300mm alone in those days, and just accept that some will be out of reach

there will still be things out of reach with 510mm

Is there anything I need to look for when buying a used 1,7 tc? Any bad copies ect.

I have not heard of any, but then I have had mine since new in 1991, don't know about the "new" ones that are appearing now

[dadipentak]

there will still be things out of reach with 510mm

I have a 1000mm lens and 1.4x, 1.7x & 2x TCs and there are still things that are out of reach! Save your money & get close.