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11-07-2018, 08:48 AM   #151
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QuoteOriginally posted by normhead Quote
If they do make a 2x it will be most useful on the DA* 200 2.8, DFA 70-20 2.8, and usably the 100 macro for those who want a nice light small telephoto option. For years I had my A 600 5.6 snd DA* 200 2.8. The 2x would have given me 400 5.6 and would have let me leave the A-400 at home. That being said, on a bright sunny day the DA*300 4 an the 2x will probably provide some decent images if circumstances are right. I wouldn't recommend buying a 2x TC for an 4 lens, but if you bought it for something else, I'd certainly give it a test run.
Well my Bigma would happily focus with the Sigma 2X matched converter so maybe applying 'Cannon' rules to Pentax AF system is flawed.

Safox will quite happily focus @F14 (ish) in good light
https://g3.img-dpreview.com/87CF9AA55F424FE885F69BD765AE4A8F.jpg
Canon not so much


Last edited by awaldram; 11-07-2018 at 08:55 AM. Reason: add image
11-07-2018, 09:06 AM - 1 Like   #152
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My problem with 2x on higher than ƒ4 is performance, not focus lock. It can be difficult to lock focus on moving targets, it takes longer sometimes resulting in missed shots.. 2.8 definitely works best, with degraded performance as your lens gets slower and slower.
11-08-2018, 12:44 AM   #153
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QuoteOriginally posted by awaldram Quote
Well my Bigma would happily focus with the Sigma 2X matched converter so maybe applying 'Cannon' rules to Pentax AF system is flawed.

Safox will quite happily focus @F14 (ish) in good light
https://g3.img-dpreview.com/87CF9AA55F424FE885F69BD765AE4A8F.jpg
Canon not so much
And I thought Pentax AF was inadequate.
11-08-2018, 05:46 AM - 3 Likes   #154
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QuoteOriginally posted by thibs Quote
And I thought Pentax AF was inadequate.
Pentax AF.c and tracking are inadequate. But you can be an AF.s shooter you can enjoy some of the best AF out there.

I just don't have a lot of cause to use tracking. So for me Pentax AF works just fine.
And when I do use tracking I get some results I wouldn't expect listening to folks on the forum complain about how bad it is. It may not be up to Canon, Nikon and Sony high end action camera standards, but it's not a complete waste of time either.


Last edited by normhead; 6 Days Ago at 08:27 AM.
11-08-2018, 10:51 AM - 1 Like   #155
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QuoteOriginally posted by normhead Quote
Pentax AF.c and tracking are inadequate. But you can be an AF.s shooter and enjoy some of the best AF out there.

I just don't have a lot of cause to use tracking. So for me Pentax AF works just fine.
I have used Canon, Nikon, Pentax and Sony and will back what Norm is saying. Single shot AF is great with Pentax, even in low light. I would avoid the 2x TC except for Macro or f/2.8 glass. There is a difference between “working” and producing quality images that I would actually keep. I prefer for poor images being the fault of a mistake I made and not a limitation of my gear.
11-08-2018, 08:13 PM   #156
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I confess I was hoping for a 1.7x FF.

The first point I'd make is that the image quality has to be very high (such as is delivered by the existing 1.4x APS-C teleconverter). There's no point in using a teleconverter if Photoshop can do as good a job in post.

Secondly, I'm almost exclusively a bird photographer, and frankly most of the time I prefer using my K-1 MkII (upgraded) in APS-C mode because: birds tend to fit into the smaller frame and you can shoot at 7 frames a second rather than 3. So, a 1.4x FF teleconverter will only have marginal value over what I already have -- I estimate that fewer than 5% of my shots are full frame; it might be as low as 2%.

Thus, a 1.7x teleconverter (even an APS-C one) would give me more range than what I already have and my sense is that to achieve the quality I see as being necessary it will be significantly more expensive than the 1.4x with a potential 2.0x dramatically more expensive and mostly more than I need in most circumstances.

FWIW, I use my 1.4x mostly with the 150-450 mm zoom. But if I'm going out with family or I'm going to be doing a long walk (particularly through sand) I'll use it with the 55-300 mm lens (I have the Pentax HD PENTAX-DA 55-300mm f/4.5-6.3 ED PLM WR RE Lens). Occasionally, I'll use it with the 300 mm prime lens. I'm pretty happy with the focusing speed in all these combinations although as others have said, tracking is frustrating. I also have a sense that focusing is not quite as good with the upgraded K-1 MkII as it was before the upgrade when I'm using spot focusing -- but that might just be that as I get older (pushing 75 right now) my handheld prowess is more shaky than it used to be!

Dave
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