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03-24-2014, 03:41 AM   #346
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+1
I guess this converter is NOT the FF-ersatz some if us would dream of !...
Better nothing

03-24-2014, 10:26 AM   #347
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QuoteOriginally posted by Zygonyx Quote
+1
I guess this converter is NOT the FF-ersatz some if us would dream of !...
Better nothing
I've posted the images from my own tests, showing that using the TC does not reduce image quality. That in fact as the length of the lens increases the quality a small centre portion of the image increases, with the longer lens used, regardless of whether or not a tac is involved in the process. This "aTC degrades the image quality, only applies to cheap glass. On my $1400 DA*60-250 or my Tamron 90 or Sigma 70, the lenses are sharp enough that expanding them 1.4 times doesn't affect resolution.... how many times do I have to post this stuff, in how many threads...

It's amazing how many people use cheap TCs with cheap glass, and then post like they know something about good TCs used with good glass. No one would dream of coming on here and saying you can't get a good image with a DA*300 because they can't get one with their 300mm lens and neglect to mention that the lens they tested on was a Sigma 70-300. Yet on TCs everyone seems to think because they've used a cheap one, they are now qualified to comment on all of them. It's BS.

The facts....

OK, since I was interested, I went out again... this time, 3 shots at each setting picked the best of each,

The scene shot at 250mm.


The test chart, cropped to the size of the chart @250mm.


The test chart, cropped to the size of the chart @350mm. DA*60-250 + 1.4


The test chart, cropped to the size of the chart @400 mm (A-400)


The test chart, cropped to the size of the chart @450mm. DA* 60-250 + F 1.7 TC


The test chart, cropped to the size of the chart @560 mm (A-400 +1.4 TC)


The trend seems to be a constant improvement with longer focal length. No apparent degradation of the image due to TC use.
I guess I'll just keep posting this test as long as people keep repeating the TC's ruin your IQ nonsense.

Last edited by normhead; 03-24-2014 at 10:44 AM.
03-24-2014, 10:47 AM   #348
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Yes, demonstrative examples.
Nevertheless, we WON'T satisfy with this TC, instead of a true FF
03-24-2014, 01:50 PM   #349
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T/C's degrade IQ regardless of expense of glass/TC for any real example.

Does it matter to a photographer? Like all things, it depends. Photozone has a good test of the Nikon 200mm F/2 lens (one of the sharpest lenses in existence) with various T/C's, showing the minimal degradation with ~$5k glass.

One of these days I might put together a good test with DOF / shutter speed constraints...

03-24-2014, 02:13 PM   #350
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QuoteOriginally posted by StigVidar Quote
The most important reason for getting a FF camera is getting better image quality than possible with aps-c.
While true, using the T/C might allow someone with a full stable of APS-C glass to move to FF and still use that glass at least temporarily. Reduces the cost of entry to FF for some who are heavily invested in APS-C. Not sure it would be a long term solution but maybe for little used lenses it might be worth while.
03-24-2014, 02:47 PM   #351
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---------- Post added 03-25-2014 at 01:53 AM ----------



"DA*300 +Pentax 1.4x Teleconverter

---------- Post added 03-25-2014 at 01:57 AM ----------



DA*300 +Pentax 1.4x Teleconverter
03-25-2014, 02:19 AM   #352
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QuoteOriginally posted by normhead Quote
I guess I'll just keep posting this test as long as people keep repeating the TC's ruin your IQ nonsense.
Please don't. For each picture that you upload, you make me feel the 'need' for that TC becoming more and more urgent (and my Kenko Pz-AF SHQ 1.5X TC drop in value).

Any chance you can test the TC on a DA*200? I have no doubts about the IQ but am more concerned about the AF capability with this particular lens.
03-25-2014, 04:38 AM   #353
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QuoteOriginally posted by normhead Quote
The trend seems to be a constant improvement with longer focal length. No apparent degradation of the image due to TC use.
I guess I'll just keep posting this test as long as people keep repeating the TC's ruin your IQ nonsense.
At what "zoom level" are you on the crop of the first 250-shot? Is it cropped beyond 100%? I wonder since it looks really not so good.

03-25-2014, 05:41 AM   #354
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QuoteOriginally posted by Tjompen1968 Quote
At what "zoom level" are you on the crop of the first 250-shot? Is it cropped beyond 100%? I wonder since it looks really not so good.
The consensus on the 60-250 at full zoom is that there was probably motion blur, there was a light wind that day.... I was shooting from my porch at the hill across the parking lot... so pretty good distance... I have better shots of the same image taken at a different time, but in this set the conditions are the same.... so, it probably would have been a better test done indoors in a warehouse or something.... and the first test I did, the 60-250 was much better, but it was just the 60-250 and the TC. People asked me to include the 1.7, and I also added the A_400.
03-25-2014, 06:04 AM   #355
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How would react an SDM lens 'converted' to screwdrive (with lens ROM mod) ?
Should be alright but, just to be sure...
03-25-2014, 07:54 AM   #356
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lens extender

I just got one, and it seems excellent on the 60 - 250 lens I just realized that to use it with a K5 you should to update the firmware to the latest version. In fact, the latest version specifically notes the extender.
03-25-2014, 08:27 AM   #357
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Oddity regarding max. aperture with Sigma 500/4.5

Just noticed that the maximum aperture of the Pentax 1.4x tc + Sigma 500/f4.5 does not read f6.3, as it should, but f6.7. Following apertures read correctly. Anyone smart enough to figure this out?
Lens alone reads f4.5 wide open.
Chris
03-25-2014, 08:32 AM   #358
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Today's capture, a couple of crows in a tree, just off the property...

A-400 + 1.4 TC = 560mm ƒ11 -1/160s -400 ISO



03-25-2014, 09:27 AM   #359
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nice, should lighten up the first a tiny bit
03-25-2014, 11:14 AM   #360
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I like the second one quite a lot
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