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05-21-2013, 04:42 AM   #1
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What are your thoughts on the Sigma 1.4x teleconverter?

I just bought this converter. Was wondering about image quality and any other advice you all might have. Yes, it is autofocus and I got it for less than $100.


Last edited by photolady95; 05-21-2013 at 04:59 AM.
05-21-2013, 05:50 AM   #2
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QuoteOriginally posted by photolady Quote
I just bought this converter. Was wondering about image quality and any other advice you all might have. Yes, it is autofocus and I got it for less than $100.
You got it for a good price if it's the EX APO DG...

It has to be better than the Vivitar Series 1 that sells for $99, and I have no complaints about the Vivitar when combined with my 55-300.

All but the indoor pics use that combo in this set.

Montezuma NWR & Audubon May 04, 2013 - a set on Flickr
05-21-2013, 03:05 PM   #3
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If it is the APO 1.4x EX or EX DG teleconverter it only fits on some specific tele lenses from sigma and pentax (F and FA lenses)

This is because the front of thenTC protrudes somewhat into the lens. You need an opening at the rear of the lens 12 mm deep 35mm in diameter.

It is NOT a general use TC
05-21-2013, 10:37 PM   #4
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Thanks boriscleto for the good news. That's some nice looking photos you have there in that link.
I have two lenses I plan to use this on, my Sigma 70-300 and my Samyang 100-500. The Samyang is an A lenses, so that combo should work without problems.

Lowell, thanks. I am not sure which TC it is. The description given only said 1.4x Sigma Teleconverter on it. And when I went back to KEH to see if I could read anything on the photo of it, it wasn't listed anymore. I assume that is because they only had that one. I have paid for 2 day shipping so I should get it Friday, then I'll let you know which one it is.
So, you're saying as long as the back of the lenses has a receding element, I should be able to use this TC on that lens?
My Samyang's back element is not right at the end, it's got a hole up the back about 2" inside.

05-22-2013, 04:05 AM   #5
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If it is the sigma APO teleconverter I can almost guarantee it won't work on the 70-300

The samyang lens is a possible
05-22-2013, 07:04 AM   #6
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Did Sigma make any other TCs not APO?
05-22-2013, 07:40 AM   #7
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AFAIK all Sigma TCs have a protruding front element. If it doesn't work out for you I can definitely recommend the Vivitar, it seems to be the same as the Tamron that used to be recommended over the Sigma.

Vivitar 1.4x Tele Converter for Pentax VIV-1.4X-P
05-22-2013, 08:46 AM   #8
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QuoteOriginally posted by photolady Quote
Did Sigma make any other TCs not APO?
perhaps in the past, but to my knowledge not in the past 10 years at least.

when I bought my APO 70-200/2.8 EX in 2003, they only had the APO teleconverters,

The teleconverters are excellent, but like some of the pentax teleconverters from the film era, have a protruding front element and are specifically designed for llong and fast tele lenses.

the lenses are also designed somewhat with the teleconverter in mind.

05-22-2013, 11:45 AM   #9
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According to fedex that thing will be here tomorrow. I'll let you know which it is then.

Boris, thanks for the link. if this TC I ordered doesn't work on the 70-300mm lens I'll buy that vivitar next month. thing is it costs too much to send something back to KEH, I usually end up keeping things. I'll probably do that with this TC too. I believe I can use on the Samyang.

Lowell, I guess I have to wait til it gets here. Thanks for the comments, though.
05-23-2013, 01:49 PM   #10
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Okay, it came today and fit with the 70-300. No protruding piece, and it is flat. I stuck it on the camera and mounted the Sigma lens. No problems. If I feel good enough tonight I'll get a photo of it. Also, it does not say APO or APO DG on it either. It says Sigma AF tele converter 1.4x.

Edit: Well, it fit, but it won't let me manual focus. The focus ring won't turn. It tries to autofocus but just doesn't get there. So, I guess I'll use it on the Samyang, and get the Vivitar one next month or the next. I just bought a newer tripod from a member in the Marketplace.

Last edited by photolady95; 05-23-2013 at 01:58 PM.
05-23-2013, 01:56 PM   #11
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interesting, it is clearly a different beast, care to post a photo of it?
05-23-2013, 02:01 PM   #12
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Read my edit part.

I'll try to post a photo tonight.
05-23-2013, 02:17 PM   #13
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QuoteOriginally posted by photolady Quote
Okay, it came today and fit with the 70-300. No protruding piece, and it is flat. I stuck it on the camera and mounted the Sigma lens. No problems. If I feel good enough tonight I'll get a photo of it. Also, it does not say APO or APO DG on it either. It says Sigma AF tele converter 1.4x.

Edit: Well, it fit, but it won't let me manual focus. The focus ring won't turn. It tries to autofocus but just doesn't get there. So, I guess I'll use it on the Samyang, and get the Vivitar one next month or the next. I just bought a newer tripod from a member in the Marketplace.


Manual focus needs the camera plus lens (if there is an AF/MF switch on it) set to MF. With my sigma 2x TC there is enough drag that MF is not practical on my 70-200/2.8. This may be the case with your TC also.

As to AF, your lens is F6.3 as I recall at 300mm, therefore the maximum aperture is too small for AF to work (typically this is F6.9 or faster). Try at a shorter focal length to see if it can achieve focus
05-23-2013, 02:22 PM   #14
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Thanks Lowell. Will try a shorter focal length. I usually shoot at f7.1 or higher.I had a hard time trying to get it off the camera though.

Last edited by photolady95; 05-23-2013 at 02:29 PM.
05-23-2013, 03:40 PM   #15
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QuoteOriginally posted by photolady Quote
Thanks Lowell. Will try a shorter focal length. I usually shoot at f7.1 or higher.I had a hard time trying to get it off the camera though.
I have found from time to time that the AF screws don't perfectly align and /or disengage

As for aperture, the setting does not matter it is the wide open aperture that matters, when you add a 1.4x to the lens it becomes an F9 lens, and is too slow to get reliable AF. But since the lens is variable aperture a shorter focal length is also faster
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