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01-18-2013, 03:30 PM   #16
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QuoteOriginally posted by audiobomber Quote
I bought a Sigma 150-500 HSM OS, but was not sharp enough at the long end for me. The Bigma is somewhat sharper from anything I've seen, and the 120-400 less sharp. The Lenstip testing is a good indicator of the performance of these lenses. Here's the 150-500 test, the rest are worth reading if you're interested in a long zoom: Sigma 50-150 mm f/2.8 APO EX DC HSM review - Introduction - Lenstip.com

After I returned the Sigma I bought a Pentax A*300 which I used alone or with a Kenko PZ 1.5X TC. It was sharp enough, and very small for the reach. The only down sides were lack of AF and some fringing in high contrast shooting, especially with the TC attached.

I now have a DA*300, which I sometimes use with the Kenko. While it's true that a TC affects IQ, I don't have any concerns with this combo. The DA*300 is so sharp and PF is so well controlled that I don't worry about cropping images to 100%. I kept the A*300 because it's so small and IQ is way above my 55-300mm.

Even if Pentax offered a 400mm f5.6, I would still prefer the DA*300 for its faster aperture. I can have 300mm f4, or I can get to 400 f5.6 with a TC. I like that flexibility. There are many occasions in a forest or at sunset when I need that extra stop, and visibility is limited anyway. The Kenko PZ TC allows AF with SDM lenses, but it has a tendency to hunt, and sometimes misses focus. As Lowell mentioned, AF is often a handicap with birds anyway, so I use MF or the dodgy AF, as the situation warrants.When Pentax releases their 1.4X TC I will jump on it, for improved AF and because the Shake Reduction will work properly with the TC (with the A*300 I can enter 450mm focal length, with the DA*300, the FL says 300mm and can't be changed). I expect it will be an expensive TC and the IQ will be worth every penny.
Thanks Dan, quite a lot of research done tonight and like you I'm swayed by the quality of the images produced by the DA300. It certainly doesn't appear to be something I would regret making an investment in. I think it may pay off to be cautious with the TC's and just live with the 300mm until the new 1.4TC gets released. At least that way I won't be dogged by any compatability issues. It seems to be a bit of a minefield when it it comes to teleconverters. Thanks for your advice. You may have succeeded in pushing me over the edge to the DA300

01-18-2013, 03:34 PM   #17
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QuoteOriginally posted by Lowell Goudge Quote
just so you know the SMC-F 1.7x AF Converter is not cheap, but when used with a good quality manual focus lens, and by this i really mean either 70-200/2.7 or a 300/4 or faster, it can produce good results.

Lenses slower than F4 are a risk, with respect to having AF function due to minimum light and contrast constraints with the AF system, but my K300/4 works well. As I said, try for a KA mount lens to get all the auto functions, as opposed to working with green button metering
I had a look through Ebay at the long 'A' lenses. Mostly in the US and thin on the ground. I suppose their retention rate speaks for their quality though. I'll keep my eyes peeled as I continue my hunt over the next few months. It will be interesting to see if the 1.4x Pentax is releasing this year will function like the 1.7AF versions do on manual lenses or be more optically passive. Thanks for the addition to my slowly expanding knowledge.
01-18-2013, 03:40 PM   #18
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QuoteOriginally posted by Kaymex Quote
I had a look through Ebay at the long 'A' lenses. Mostly in the US and thin on the ground. I suppose their retention rate speaks for their quality though. I'll keep my eyes peeled as I continue my hunt over the next few months. It will be interesting to see if the 1.4x Pentax is releasing this year will function like the 1.7AF versions do on manual lenses or be more optically passive. Thanks for the addition to my slowly expanding knowledge.
I expect that the 1.4x converter will only be a passive converter, with no internal focusing elements, it will pass focusing data through to the lens
01-18-2013, 03:42 PM   #19
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QuoteOriginally posted by kcmadr Quote
See here for some info on the DA* 300mm F4
https://www.pentaxforums.com/forums/317890-post29.html
It describes the compatibility of this lens when used on a full frame camera.

Another telephoto option becoming more apparent for some shooters is to get the Q, the K to Q lens adapter, and you've got a 5.5x crop factor. Really excellent quality primes in the order of 100mm can be had for relatively few $ - in your case - and your 135mm effectively becomes a 740mm lens. But I will stress that to even consider this option, the lens needs to be top shelf quality. Any imperfections are exacerbated by the extreme crop factor. See here for some info and potential results: The Pentax Q - a real World user review

It might be inexpensive, but it may not suit you...
Thanks Mike. I did look at the Q and think it will make a good future investment. I know a lot of Nikon wildlife photogs are packing a mirrorless V1 with a 300mm now instead of carrying 400, 500 etc.. lenses. I suppose the difference is that they're taking advantage of a 2.7x increase whereas Pentax users see a much bigger increase. I've seen some results using the DA300 and the Q and while there is some loss of quality it's not as much as I would imagine. Knowing the Q option is there to extend the reach for a mere 200 does make me think that getting the DA300 is a good investment. It looks like I'll head for the DA300 then invest later in the new 1.4x and look at buying the Mrs a Q for Christmas ! (Homer's Bowling ball springs to mind !) Thanks.

01-18-2013, 07:38 PM   #20
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QuoteOriginally posted by Kaymex Quote
I'm swayed by the quality of the images produced by the DA300. It certainly doesn't appear to be something I would regret making an investment in. I think it may pay off to be cautious with the TC's and just live with the 300mm until the new 1.4TC gets released. At least that way I won't be dogged by any compatability issues. It seems to be a bit of a minefield when it it comes to teleconverters. Thanks for your advice. You may have succeeded in pushing me over the edge to the DA300
I've read two Pentax boards daily, since before the DA*300 release. I don't recall anyone ever saying they regretted buying one.

The owner of this site seems to think the Pentax TC will be released this month. Here's hoping he's right.
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