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View Poll Results: Are you interesting in a comparison of 1.5x TC and 2x TC vs 55-300?
Sure, why not? 1392.86%
No thanks.   00%
I'd prefer waffles vs. pancakes vs. french toast 17.14%
Voters: 14. You may not vote on this poll

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04-21-2010, 01:57 PM   #1
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Interest in a Teleconverter comparison?

Just a little poll to gauge interest in a TC comparison. I have a Kenko 1.5x and 2x TC, and the 55-300mm lens. I'd do field testing, sample shots, etc. Any interest out there?


Last edited by flippedgazelle; 04-21-2010 at 03:15 PM.
04-21-2010, 04:24 PM   #2
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Hmmm, maybe 2 votes out of 39 views is telling me something...
04-21-2010, 05:03 PM   #3
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Not for nothing but why not just do the compare and post the results?? Do you really need a poll to make the decision to take some (controlled) photos with the combos? I would think that a results thread would generate more interest than a Should I ....

Other people's mileage may vary..

04-21-2010, 05:55 PM   #4
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QuoteOriginally posted by JeffJS Quote
Not for nothing but why not just do the compare and post the results?? Do you really need a poll to make the decision to take some (controlled) photos with the combos? I would think that a results thread would generate more interest than a Should I ....

Other people's mileage may vary..

I was thinking about posting a few comparo shots, but if there is a fairly sizeable interest, I would definitely go more in depth, explore the handling of each TC, explore usage in different scenarios.

And, of course, this would be a good thread if someone had a suggestion.

04-21-2010, 06:46 PM   #5
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QuoteOriginally posted by flippedgazelle Quote
I was thinking about posting a few comparo shots, but if there is a fairly sizeable interest, I would definitely go more in depth, explore the handling of each TC, explore usage in different scenarios.

And, of course, this would be a good thread if someone had a suggestion.
I think starting a thread making some compares instead of asking if it should be done might generate more interest and participation. That's all I was saying. Of course, as a general rule, I sort of despise polls (of all sorts). This one may prove to be more useful than some but right now, you and I are the only posters

04-22-2010, 06:04 AM   #6
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QuoteOriginally posted by JeffJS Quote
...and I are the only posters

Yeah, point taken.

It does look like there are a few folks interested, though, so I'm going to do a little bit of an expansive comparison.
04-22-2010, 06:24 AM   #7
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Just having ordered the Kenko Pz-AF 1.5X, yes I'm interested. Out of curiosity an open question:

I often read that one would be better off cropping the image rather than using a converter because the drop in IQ when using a TC just about equals the loss of pixels when cropping. That sounds reasonable.

The one thing I never see is just an assumption I have: by using a TC, you are forcing the ligfhtmetering system to consider only that portion of image that you want exposed correctly. When cropping, the camera lightmeter will have exposed on the basis of metering the whole uncropped scene and your cropped portion might be adversely affected by extremely dark (or light) parts of the scene that are outside the cropping rectangle.

True or false?
04-22-2010, 06:59 AM   #8
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I'd be happy to see the results of a test that quantitatively tests TCs with the DA 55-300 at 300.

My own limited tests show the Kenko 1.5x to be of no benefit regarding sharpness at a constant image size.

For a while I doubted it was possible for a TC to do any better than cropping, but some photozone.de data with a canon system shows otherwise.

But I am stymied; I've seen no quantitative data indicating the existence of an effective TC for the DA 55-300.

04-22-2010, 07:08 AM   #9
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QuoteOriginally posted by newmikey Quote
Just having ordered the Kenko Pz-AF 1.5X, yes I'm interested. Out of curiosity an open question:

I often read that one would be better off cropping the image rather than using a converter because the drop in IQ when using a TC just about equals the loss of pixels when cropping. That sounds reasonable.

The one thing I never see is just an assumption I have: by using a TC, you are forcing the ligfhtmetering system to consider only that portion of image that you want exposed correctly. When cropping, the camera lightmeter will have exposed on the basis of metering the whole uncropped scene and your cropped portion might be adversely affected by extremely dark (or light) parts of the scene that are outside the cropping rectangle.

True or false?
I can tell you, after a few hudnred shots with the 1.5x and 2x TC's, that the IQ with the TC can be noticeably better with the TC. Here's an example of a scenario where the TC helps: you see a bird sitting in a tree. You can see the bird well enough to ID it, but you can only fill around 1/4 of the frame with it. You will see more detail using the TC than w/o it.

We're talking decent TC's here, not the $20 ones on fleabay.

Point #2 is true. Unless you are using spot metering, of course.
04-22-2010, 07:13 AM   #10
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QuoteOriginally posted by newarts Quote
I'd be happy to see the results of a test that quantitatively tests TCs with the DA 55-300 at 300.

My own limited tests show the Kenko 1.5x to be of no benefit regarding sharpness at a constant image size.

For a while I doubted it was possible for a TC to do any better than cropping, but some photozone.de data with a canon system shows otherwise.

But I am stymied; I've seen no quantitative data indicating the existence of an effective TC for the DA 55-300.
Hopefully, I'll be able to provide enough information to satisfy you.

Briefly, though: there is a specific set of parameters where the TC is beneficial. Outside of these parameters, there is no improvement. And, IMO, field usage is not to be discounted.
04-23-2010, 06:13 PM   #11
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Kenko TC

I appreciate your work in trying to figure it out. So, your conclusion is that the 1.5 is useful where you want move in on a small object (song bird in a tree) and get accurate metering. You are saying that the Kenko does not degrade the IQ much when used...? So, it is worth the $130 plus, to get the extra reach... or would it be better to save for the Pentax TC's that show occasionally? I had a Quantaray 2x and it did not do as well as the lens cropped. I can't afford to waste the money if it doesn't help.
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