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05-03-2008, 12:13 PM   #301
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Used Tamron 1.4x teleconverter with 8+ rating for $50 shipped at Robert's Imaging.

Tamron 1.4x teleconverter

05-05-2008, 08:03 AM   #302
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Thear!! I think I purchased it!!!!! I called them up and they said still processing (from a order over the weekend) so not sure but THANK YOUUUUU if I am the winner of this TC ))
05-10-2008, 10:56 PM   #303
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I have started to look for another MC-4 model with no such luck.
05-13-2008, 02:27 PM   #304
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Hi Folks,
A few weeks back I bought this TC on eeekkkkbay and to my surprise it is not too bad. It is a 2xtc that shipped to my door brand new cost $65.00...I have only tested it on my Sigma 70-300APO and auto focus actually works...While the images are a tad soft, many where actually ok...According to the website I bought it from, it is suppose to work with SDM lenses as well...I have not tested this ''yet'' but will pretty soon....I have two other 2x TC's...The tamron version and the Pentax manual version..Both of those are not even in the same class as this generic $65.00 tc from what I have seen so far...

Has anyone else ever heard of this brand or tried one out? The way I see it, if it worked on a 300mm F/5.6 Then surley it should amaze on an F/2.8 OR F/4.0...I will soon see...









Here is what I bought.
NEW 2x AF TeleConverter for Pentax SLR K100D K110D K10D - eBay (item 110245010416 end time Apr-23-08 20:37:58 PDT)

05-13-2008, 05:29 PM   #305
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I haven't heard of this brand before, but i do look forward to more pics from the 2x TC.
05-13-2008, 05:48 PM   #306
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QuoteOriginally posted by jgredline Quote
Here is what I bought.
2x AF TeleConverter for Pentax
Hi Javier,

this is a 4 lens elements 2x TC. Aren't the other 2x converters all 7 elements, with only 1.4x being 4 elements?

Will be interesting to compare the optical quality.

Nice addition to the collection!
05-13-2008, 07:03 PM   #307
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QuoteOriginally posted by falconeye Quote
Hi Javier,

this is a 4 lens elements 2x TC. Aren't the other 2x converters all 7 elements, with only 1.4x being 4 elements?

Will be interesting to compare the optical quality.

Nice addition to the collection!
Traditionally, "cheap" 2x TCs had 4 elements, while the better ones had 7. The 4-element ones I have tried were not that great. I have a 7-element Tokina waiting to be tested, but I haven't had the time.

I'm surprised that this 4-element TC works well. But I'll wait further testing from Javier to cry victory.
05-13-2008, 08:10 PM   #308
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OK, Here are some snap shots I took on my way home from work. Body is the K10D and Lens was the Sigma 135-400 apo.

This image was shot at 135mm x CHEAPO 2tc = 270mm..I find it pretty OK....



05-13-2008, 08:21 PM   #309
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These next few where shot at 400mm @ f/5.6 x cheapo 2X TC = 800mm and auto focus did work, BUT Pretty soft..These where the best of the 22 photos I shot today....What do u thinK? I think for what it cost, it is not to bad...The light was pretty good out so I don't think I could have done much better.
Keep in mind though that this F/5.6 is now F/11 if my math is right....

Shooting into a tree with branches. Still was able to focus on the bird, I think...


Shooting into shadows


Appx 35-40 yards away




Shooting into the middle of the pond so appx 50 yards.
05-13-2008, 08:24 PM   #310
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I did not catch that it was 4 elements. I wonder if this is why Autofocus still works?
05-14-2008, 06:35 AM   #311
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QuoteOriginally posted by jgredline Quote
Sigma 135-400 apo. [...] at 135mm x CHEAPO 2tc = 270mm..I find it pretty OK....
The images look ok.

You probably had downsized for the web.

I ask because the true test for a TC of course is in comparison with a digital 2x zoom, i.e., the 2x TC image at 100% crop vs. the original upsampled to 200% using bicubic interpolation / mild sharpening. Only if the TC then looks better it actually makes sense to use it

It's a tough test for a TC...
05-14-2008, 07:06 AM   #312
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QuoteOriginally posted by falconeye Quote
The images look ok.

You probably had downsized for the web.

I ask because the true test for a TC of course is in comparison with a digital 2x zoom, i.e., the 2x TC image at 100% crop vs. the original upsampled to 200% using bicubic interpolation / mild sharpening. Only if the TC then looks better it actually makes sense to use it

It's a tough test for a TC...
I did resize and some cropping, but no PP work what so ever. no sharpening or anything.
Here is a 100% crop of the above image.
05-14-2008, 10:11 AM   #313
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QuoteOriginally posted by jgredline Quote
Here is a 100% crop of the above image.
Ok, not having the corresponding image w/o TC, I downresized to 50% size and then compared, i.e., I upsized to the original size again.

There is no noticeable difference to the original, i.e. for this particular image, the TC was totally ineffective. If it doesn't do any better than a digital zoom, I would drop it.

Maybe, other lens, apertures or shutter speed combinations yield a better result? Maybe, it's just soft focus.
05-14-2008, 10:29 AM   #314
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QuoteOriginally posted by falconeye Quote
Ok, not having the corresponding image w/o TC, I downresized to 50% size and then compared, i.e., I upsized to the original size again.

There is no noticeable difference to the original, i.e. for this particular image, the TC was totally ineffective. If it doesn't do any better than a digital zoom, I would drop it.

Maybe, other lens, apertures or shutter speed combinations yield a better result? Maybe, it's just soft focus.
Yea, I did not even stop to think about it. You are right. I did not take any pictures with out the TC. Even though, I know this lens I was using is pretty good on its own. I can see how much the TC hurt the image though...I have yet to see a good 2xtc of any sort. It appears Pentax also knew this, hence the 1.7 which I hear is pretty good. I have one of those on the way that I bought from a member here. I look forward to getting it and trying it out.
05-14-2008, 11:01 AM   #315
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QuoteOriginally posted by jgredline Quote
Yea, I did not even stop to think about it. You are right. I did not take any pictures with out the TC. Even though, I know this lens I was using is pretty good on its own. I can see how much the TC hurt the image though...I have yet to see a good 2xtc of any sort. It appears Pentax also knew this, hence the 1.7 which I hear is pretty good. I have one of those on the way that I bought from a member here. I look forward to getting it and trying it out.
The only way a 2xTC is going to give you better then average results is if the lens your using it with is excellent.. not average but REALLY excellent. I'm shocked that it AF'd at all with a 5.6 lens, making me wonder just how accurate that focus was.

The Sigma 135-400 isn't an "excellent" lens so I'm not surprised by these results at all, especially with an unknown brand TC. For example, if you take a look at some of those Sigma 70-200EX shots in that other thread taken with the Sigma 2xTC you'll see MUCH better results.. like below.

Also don't forget that SR doesn't know about the TC so it still thinks your shooting at 400mm, not the 800mm when including the TC.




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