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Old Dec 17, 2011, 2:48 PM   #1
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Default Teleconverter or no?

I tried an experiment this afternoon to see what sort of damage my Tamron 1.4x Pro teleconverter does to the image from my 70-300mm SP Tamron lens output. I simply took a shot at 100mm w/ the teleconverter, then shot the same scene at 140mm without the teleconverter.

Here's the two shots:
#1 Full
Name:  IMG_4725.jpg
Views: 239
Size:  237.6 KB
#2 Full
Name:  IMG_4726.jpg
Views: 215
Size:  215.4 KB

And the 100% crop:
#1
Name:  2crop.jpg
Views: 199
Size:  239.8 KB
#2
Name:  1crop.jpg
Views: 200
Size:  251.8 KB

Thoughts?
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Old Dec 17, 2011, 6:33 PM   #2
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That looks pretty good. But Tamron's Pro teleconverters are some of the best, so that's not so surprising.
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Old Dec 18, 2011, 2:55 PM   #3
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G'day Jim

Nice pair of images ~ but it's really hard to tell when scrolling up & down the screen
May I suggest you create a new canvas & paste 2 half-images side by side so that you / we can eyeball them directly

ie- End up with something like the image I have posted in the thread "Which of thies accessories u think worth ??"

Regards, Phil
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Old Dec 18, 2011, 3:08 PM   #4
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That converter appears pretty darn good- even at a decent crop.
I wonder- are there any variants in IQ across the frame- say near the outer 10% of the image..?
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Old Dec 18, 2011, 3:10 PM   #5
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I can't discern any difference in the images, except for the background being slightly less blurred with the t/c, which is only natural.

brian
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Old Dec 18, 2011, 7:47 PM   #6
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Phil, that was impressive work. I've already deleted those files, so I'll have to give it a go next time.

These photos were shot at ISO160 and 1/200s. The first image w/ teleconverter was shot at 104mm, f5.6. The second shot was taken at 141mm, f8 to account for the loss of light with the teleconverter. I was pleased to see that the zoom hit so close to what I wanted.
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Old Dec 18, 2011, 8:47 PM   #7
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There seems to be a bit more CA also. But very little to be noticeable in the full photo.
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Old Dec 20, 2011, 12:11 PM   #8
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Looks more than good enough to use any there is a need.
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