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05-23-2017, 01:33 PM   #1
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guess the cheap 2x converter.

Yeah you will all get it right.
I did some testing today just to see the trade of of vintage to the da 50-200mm. I have collected vintage lenses to get fast apertures cheap. Yet at the 200mm end fast glass is not cheap so the best I can do is f4 vs the 50-200da f5.6. So I did some comparing at 100 to get a feel for the 200 range. Sure I have to extrapolate but I think I did get a good ballpark idea. I will stick with the da until I can afford fast glass.
I have a cheap <$10 deitz 2x with a 50 1.7a at f2.8, a Nikkor 100 2.5, a <$10 sears 80-200 f4, and a Tamron 18-250. So I tried them all at the 100 range at f5.6. Focused each 5 times and the auto ones 5 times both manual and AF, (the AF won in quality and consistency).
I only took a small portion from the center of each unprocessed jpeg. Thought the results would be interesting to some of you.

---------- Post added 05-23-17 at 01:59 PM ----------

so I wanted to post which is which.
1= sears 80-20 f4
2=Tamron 18-250
3=DA-L Pentax 50-200 wr
4=Nikkor 105 2.5
5=Deitz 2x teleconverter with Pentax A 50 1.7

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05-23-2017, 04:17 PM   #2
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Interesting. I am surprised that the tamron 18-250 was that bad at 100. It's near the sweet spot of that lens at 5.6. Many have argued that is at least as good as the 50-200 DA. Am I looking at that right? The Deitz converter combo is pretty awful :-). Almost so bad that it's "artistic".
05-23-2017, 04:59 PM   #3
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QuoteOriginally posted by Pentax Syntax Quote
I am surprised that the tamron 18-250 was that bad at 100.
So am I. I had that lens for about 7 years and it was definitely better than that. Stopped down it was very good (in the centre at least).

I also had the A-50 f1.7. It's a nice sharp lens. The take-home is that a nasty TC can ruin images from a good lens.

Thanks for the comparison.
05-23-2017, 05:38 PM - 1 Like   #4
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I have taken great pictures with the tamrom. It surprised me also. It was low light and flash so that might be part of it. My 50a 1.7 is great on its own. The sears surprised me too.
After i posted i tried my <$10 2x kenko m42 that came yesterday with my takumar 135 2.5 and that gives me a nice f5 270 but its short of infinity. Out testing right now, beer brake.

05-23-2017, 06:46 PM - 1 Like   #5
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this kenko 2x m42 did much better but this is 270 f5 now. not to shabby.
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05-23-2017, 06:52 PM - 1 Like   #6
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Funny... I have a 'few' 2x lens extenders, and for grins - bolted them all in series with a Rokinon 85mm f/1.4 to get a decent shot of the moon.
It wasn't as bad as many would expect.
05-23-2017, 11:00 PM   #7
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QuoteOriginally posted by formercanuck Quote
Funny... I have a 'few' 2x lens extenders, and for grins - bolted them all in series with a Rokinon 85mm f/1.4 to get a decent shot of the moon.
It wasn't as bad as many would expect.
Not quite a ringing endorsement. ;-)

Were any of them any good?
05-24-2017, 06:59 PM   #8
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I tried again to get better results including live view and daylight. I might have got a little improvement but not much. The Tamron improved much but still not great by going to f11 in daylight. I hand held at about the same distance with shutter at 1/1000

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