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11-16-2009, 12:32 PM   #1
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Teleconverter with DA* 50-135?

Like the title says, can I use a teleconverter with the DA* 50-135? Will I get a reduction in the aperture opening? I like that lens for the f2.8 as well as the weather sealing, but I think it's weakness is the short 135mm focal length. There is of course the *60-250 but it's twice the price and only F4.

11-16-2009, 12:53 PM   #2
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Never tried a TC on the 50-135, so couldn't help you there, but TCs do reduce the effective aperture by 1 stop (for 1.4x), 1.5 stops (for 1.7x) and 2 stops (for 2x).

You want something longer but still want f/2.8 - you'll have to go to one of the 70-200 f/2.8 offerings, or invest in Pentax's FA* 80-200.
11-16-2009, 01:29 PM   #3
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Ok, so not too far away from the 60-250 then in terms of light with a TC. It's almost like having two lenses in one!

Someone please talk me out of this lens, too tempting!
11-16-2009, 01:52 PM   #4
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If you're referring to the 50-135 + TC, don't hold your breath. AF performance on SDM lenses have not been all that impressive with the current lineup of SDM-compatible TCs. The Tamron 1.4x TC is probably the closest to working with SDM lenses, but it works more reliably with screwdrive lenses like the Tamron 70-200.

11-16-2009, 01:58 PM   #5
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I have this DA*50-135 and have tried it with:
- Tamron 1.4x TC (auto focus)
it works but needs a good light. If the light level is low or dim, you'll get frustrated using this combo. The focus will hunt and takes a while before it stops focusing or not at all. So it's a 50:50 situation. You get the extra reach for sure and not too bad IQ but I'd say just forget about the auto focus.

- Vivitar 2x MFTC (Macro, manual)
with this TC it will work since it's manual anyway. The good thing with this TC is even though you will lose 2 stops, the IQ is just amazing. My copy is very good. I couldn't even any loss in IQ using this TC and any lens. I never used the regular 2x TC but from what I read the IQ will drop significantly. With this Vivitar 2x MFTC, I haven't seen anything bad comes out of it.
This same TC turns my already sharp FA 43Ltd into an unbelievably sharp 86mm MACRO Limited
11-16-2009, 05:00 PM   #6
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I have tried my 50-135 with both the A 1.4X-S and F 1.7X AF converters. The image quality is really quite good. So I have a manual focus 70-190 f/4 and an 85-230 f/4.8 lens with automatic focus touch up. I have only done quick tests at about 7 metres (the width of a room with bookshelves at the far end), but the lens looks to be quite useful with either. I have not dared to stack them to see what I would get. Yet.
11-17-2009, 03:32 PM   #7
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QuoteOriginally posted by sebberry Quote
Ok, so not too far away from the 60-250 then in terms of light with a TC. It's almost like having two lenses in one!

Someone please talk me out of this lens, too tempting!
I think you will find the numbers tell a small part of the story.

The 50-135 is a blistering lens in it's own right, but put it on a TC and two things will happen. The IQ will be lowered and the autofocussing will be much slower and less reliable.

Hold out for the 60-250.
11-17-2009, 03:38 PM   #8
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QuoteOriginally posted by Oggy Quote
I think you will find the numbers tell a small part of the story.

The 50-135 is a blistering lens in it's own right, but put it on a TC and two things will happen. The IQ will be lowered and the autofocussing will be much slower and less reliable.
Thanks for the info.

QuoteOriginally posted by Oggy Quote
Hold out for the 60-250.
Up here it's $2100 lens with taxes. I'm just a hobbyist, not a pro

11-17-2009, 04:52 PM   #9
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I have the Tamron 1.4 teleconverter and the 50-135mm. Did a test with them last week and see no degradation whatsoever. Autofocus does hunt just a little more in the shade or dimmer light but in daylight it is pretty much a non issue. I have seen reports on the same combo to the contrary. I am happy with the combination myself. I rented a 60-250 in October to use on a whale watching cruise in Seattle. After hauling the lens around for 4 days the second picture I took did not focus and after that it was very hard to zoom and the stiffness varied from turn to turn of the zoom collar. I took the lens off the camera and looked through it and could see an "O" Ring hanging down. Something failed inside of the lens. Probably a seal. After that I boought the Tamron MC 1.4 converter to achieve some of the same focal lenngth while carrying around a much lighter lens. It will do for now.
11-17-2009, 04:59 PM   #10
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QuoteOriginally posted by GaryH Quote
I have the Tamron 1.4 teleconverter and the 50-135mm. Did a test with them last week and see no degradation whatsoever. Autofocus does hunt just a little more in the shade or dimmer light but in daylight it is pretty much a non issue. I have seen reports on the same combo to the contrary. I am happy with the combination myself. I rented a 60-250 in October to use on a whale watching cruise in Seattle. After hauling the lens around for 4 days the second picture I took did not focus and after that it was very hard to zoom and the stiffness varied from turn to turn of the zoom collar. I took the lens off the camera and looked through it and could see an "O" Ring hanging down. Something failed inside of the lens. Probably a seal. After that I boought the Tamron MC 1.4 converter to achieve some of the same focal lenngth while carrying around a much lighter lens. It will do for now.
Thanks for the feedback.

I suppose being a rental the 60-250 might have been treated a bit diferently but to hear about something like that on a lens of that price is a bit disappointing. I can see a two year warranty on the DA series, but IMO the DA* should come with a 5 year if not more.
11-18-2009, 10:52 AM   #11
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I was very disappointed in the 60-250 failure. Was really considering that lens. Now I beleive the Sigma 100-300 f4 might suit my needs better. I like the idea of internal zooming like the 50-135 has. Ended up taking whale pictures with a 17-70. Not much in the way of close ups....
I can send you comparison pictures with and without the teleconverter if you would like. Just PM me your email.
11-19-2009, 07:34 AM   #12
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Well, after reading this and coming across a relatively inexpensive used Tamron 1.4x, I decided to buy it and give it a try with my 50-135mm... and here I thought today might be the day I finally leave my credit card in my wallet (and not purchase any Pentax related products).

QuoteOriginally posted by GaryH Quote
I have the Tamron 1.4 teleconverter and the 50-135mm. Did a test with them last week and see no degradation whatsoever. Autofocus does hunt just a little more in the shade or dimmer light but in daylight it is pretty much a non issue. I have seen reports on the same combo to the contrary. I am happy with the combination myself. I rented a 60-250 in October to use on a whale watching cruise in Seattle. After hauling the lens around for 4 days the second picture I took did not focus and after that it was very hard to zoom and the stiffness varied from turn to turn of the zoom collar. I took the lens off the camera and looked through it and could see an "O" Ring hanging down. Something failed inside of the lens. Probably a seal. After that I boought the Tamron MC 1.4 converter to achieve some of the same focal lenngth while carrying around a much lighter lens. It will do for now.
11-19-2009, 08:06 AM   #13
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I have a pentax-A 2x TC used on 50-135, the result is very good.
11-19-2009, 12:18 PM   #14
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Thanks for the feedback everyone, and thanks Gary for the shots! You might want to post one or two here so people can see the results
11-19-2009, 01:28 PM   #15
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QuoteOriginally posted by sebberry Quote
Thanks for the feedback everyone, and thanks Gary for the shots! You might want to post one or two here so people can see the results
I had, like others, read some post about TC's not working well with the 50-135. I just tried it myself. Glad i did.

I have the Tamron 1.4 with power zoom contacts, enabling SDM. Today in my area its very gray with constant rain, noon. I focused on some very fine branches on the side of a tree abt 35 feet away. The SDM locked but when i checked the image at 8X magnification on the LCD, it was not acceptable sharpness. When i manually focused, i got an acceptable sharpness at 8X LCD zoom (equiv to 100% crop, i believe) This was at 1/250 shutter, 2.8 aperture, and 800 ISO, handheld.

This is great news. I have no doubt in normal daytime lighting that this combo would focus on SDM. And even in less light, i could always use manual focus with this combo. And as someone else said, the 50-135 is far lighter than a 70-200 to carry around.
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