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05-26-2016, 07:51 AM   #31
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QuoteOriginally posted by normhead Quote
Every now and then I nail one with the A-400 and the 1.4. but, it's been a while. With the 1.4 it's still plenty sharp enough. With the 1.7 I think you are testing the resolving power of the lens.
Oh, no doubt I am doing hell to the A400 with the old 2x TC But it's fun! And it's giving me a chance to evaluate the usefulness of the combo in terms of handling and focal length, in case I want to buy the Rear Converter-A 2x-L, which is a match for the lens.

I once had the Rear Converter-A 1.4x-S and had good success with it on a 300mm Tak, but I wasn't comfortable using it with the A400. I probably should have spent more time learning the combo before selling the TC.

05-26-2016, 04:28 PM   #32
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Norm, is that a variety of flycatcher in your post #25? The head shape says flycatcher to me. King birds and Phoebes are my friends.

I hope to sometime have a TC in the 1.4-1.7 range, and if I had one of them, I would probably use a TC much more often, mainly since there would be less light loss. So far I have only owned 2Xs and for a time a 3X.

I have something else in my kit that is sort of like using a 1.5X TC -- putting a lens on my cropped sensor K110D dslr! It gives an apparent big boost to focal length compared to using the same lens on a full-frame film body.
05-26-2016, 06:05 PM   #33
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That's a Pine Siskin, a whole flock of them, about 400 birds stayed at my place for about a month waiting for the weather to break further north.
06-04-2016, 02:30 AM   #34
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I still get the impression that if you need 600mm+ a 150-600 provide more than a DA*200 or DA*300 would do with all the TC you'll want. You get f/6.3 instead of f/8-f/9 equiv.,n you get better AF and you still have zooming capabilities that the prime + TC will not have.

Funily if you read people that brought a K1, a body with a bit less magnification than best APSC, people are more satisfied. Because AF work better, because you get 1.22 stop in theory from sensor size, more like 2 stops in practice of noise control meaning a 150-500 act more like a 100-350 f/2.5-3.2 lens on a K3 and that something that can't be brought. A 150-600 if we could have one on K mount on a a recent FF would act like a 100-400 f/2.5-3.2 on a K3.

You combine the low light capability of the DA*200 without TC of normhead but with more reach and details than a DA*300 all with zooming capabilities.

Hopefully K3 successor will get back the noise/iso difference to 1.22 stop like the theory says so a 150-600 on FF will be equivalent "only" to a 100-400 f/3.2-4 on APSC, but nothing is sure, manufacturers may want to keep big difference in performance to bring people to buy the more expensive FFs.

The thing is a DA*200 may very well outresolve a K3-II 24MP sensor in the center stopped down to f/4 or f/5.6, but it may not outresolve a 216MP sensor that would allow to get 24MP worth of detail at 600mm cropped. Sure a DFA100 macro might be able to handle better a 3 time increase in focal length, but the issue is always the same. Longer focal length need bigger/heavier lenses to resolve more details and so the longer focal length you buy, the more you have the spend or the less margin you get and so the less usefull a TC will be.


Last edited by Nicolas06; 06-04-2016 at 02:38 AM.
06-11-2016, 01:51 PM   #35
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If you need 600 plus, then the Sigma 500 ƒ4.5 with the 1.4 is probably the way to go. Or maybe an A*400 ƒ2.8 with the F 1.7x AF adapter. When I want 600 plus I go with the A-400 and 1.7 But that's 9.3 and 680 and a very crippled AF system. At no point does a 150-600 lens that is ƒ5 at 150mm enter my mindset.

The Pentax 150-450 with the 1.4 is really the only option I'd consider in a zoom. That's 680mm at ƒ8, So I have an ideal solution for getting over 600mm and a not so ideal but functional solution, none of which involve 150-600mm lenses. ƒ6.3 is just too slow. Many of the shooters I know shooting Nikon and Canon gear shoot 600mm ƒ4.
06-11-2016, 03:19 PM   #36
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How about a 300/2,8? With the appropriate ammount of TCs you get decent apertures:
300x1,4 = 420mm f/4
300x1,7 = 510mm f/4,8
300x2,0 = 600mm f/5,6
300x1,4x1,7 = 714mm f/6,7
300x1,4x2,0 = 840mm f/8
300x1,7x2,0 = 1020mm f/9,6

I'm glad I went for a 300/2,8 in stead of a 500/4,5 even if the last one have a slightly larger aperture diameter (111 vs 107 mm).

I have have a plan about taking comparable photos with this lens and various combinations of TCs (1,4 and 2,0), but I haven't taken those shots yet.
06-11-2016, 04:24 PM   #37
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QuoteOriginally posted by Simen1 Quote
How about a 300/2,8? With the appropriate ammount of TCs you get decent apertures:
300x1,4 = 420mm f/4
300x1,7 = 510mm f/4,8
300x2,0 = 600mm f/5,6
300x1,4x1,7 = 714mm f/6,7
300x1,4x2,0 = 840mm f/8
300x1,7x2,0 = 1020mm f/9,6

I'm glad I went for a 300 ƒ2.8 in stead of a 500/4,5 even if the last one have a slightly larger aperture diameter (111 vs 107 mm).

I have have a plan about taking comparable photos with this lens and various combinations of TCs (1,4 and 2,0), but I haven't taken those shots yet.
I did consider a 300 2.8, and that in many ways is the optimum, but, the 200 2.8 is so much more portable, and affordable.
02-03-2019, 09:25 PM   #38
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Upping the geek level a bit now.
A lens will perform better on a high resolution sensor but will fall of from the best that sensor can perform.
It seems that doubling from 2k to 4k loses much less than doubling from 4k to 8k in a log function. And different magnification amplifies this. So the cropping of a photo at 8k by 1.4 will much more effect than 2k by 1.4.
I have nothing but assumption for the tc effect. If it's degradation of the image is linear or simply a different log function then there will be a resolution for each lens + tc on equal quality sensors of different pixel density where a tc is better than crop or worse. This suggests that the higher pixels the more the tc is an advantage.
Of course I could find nothing about this. I base this on the findings of this article.
Lens Rentals | Blog
If this is correct thinking then a crop mode + lens picture cropped on the k1 will perform more favorable to a crop mode +lens + tc.
And a lens + k1 photo cropped will perform less favorable to a lens + tc + k1.

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