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09-02-2010, 11:06 AM   #1
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DA 70mm and 2X TC - A 2-part Question

Hello All,

In my seemingly endless pursuit of the perfect "minimalist" travel kit, I'm looking to answers to a couple of questions (if Pentax would make a DA 135mm in the same size as the M 135, I wouldn't have to ask this!):

1) Anyone have any experience using the DA 70 with a 2x teleconverter? I don't have experience with TCs. I know a 2x costs two stops of light (would this make the DA 70 an f 5.0 or 5.6?), and I know it degrades IQ a bit. I am simply wondering if the results are good with this combo nonetheless.

2) Anyone have any experience with the Vivitar 4 element 2x TC? Here is the link, I can't find any solid reviews of it: Vivitar 4 Elem 2X AF TeleConverter 2XMC4 For Pentax K-x - eBay (item 130382015318 end time Sep-06-10 19:35:21 PDT)

Thanks for any/all help!

Todd

09-02-2010, 11:31 AM   #2
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I don't have any idea what the trade-off in practical, useful IQ might be versus the DA 70 + TC but this seems a perfect opportunity to consider the DA 50-200WR. You'd gain a LOT of versatility and additional FL options with no need to carry the second component at all and only loose about one stop at 70mm.

H2
09-02-2010, 12:08 PM   #3
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a 4 element TC is not the best option.

You are better off with another approach.

you woud actually be much more pleased with an M135F3.5, which would be small light and more than a stop faster than the DA70 with TC, or go for some more weight and get a K135F2.5 which is an exceptional lens.
09-02-2010, 02:45 PM   #4
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@ pacerr: Thanks for the reply. I've owned the 50-200 before, and now own the 55-300. I'm not willing to give up the 70 Ltd's image quality for a zoom, so to get more reach with the zoom it would have to be in addition to the 70, which makes the kit bigger than I want. The TC would only add minimal bulk.

@ Lowell: Thanks for the idea. I've owned the M135 twice, and it is a solid lens. However, the problem is I want the 70 Ltd as part of the kit, and the extra length is for those times I need a bit more. So, I dumped the M135 because it was an extra lens, not a replacement for the DA 70. You mentioned the 4-element is not a good option...is there a better option when it comes to TCs?

09-02-2010, 03:48 PM   #5
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QuoteOriginally posted by gnaztee Quote
...is there a better option when it comes to TCs?
Tamron and Kenko have 7-element TCs but I've no experience with them. (Google either + MC7 for many hits and opinions.)

I'd consider the Tamron PZ AF 1.4X MC4 as a suitable alternative. I've been satisfied with my experience with that and it's about 1/2 the size of the 2x's with only one stop penalty.
IME, you break even between the 2X's and cropping the 1.4X TC and have a little better contrast.

H2
09-02-2010, 04:00 PM   #6
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QuoteOriginally posted by gnaztee Quote
@ pacerr: Thanks for the reply. I've owned the 50-200 before, and now own the 55-300. I'm not willing to give up the 70 Ltd's image quality for a zoom, so to get more reach with the zoom it would have to be in addition to the 70, which makes the kit bigger than I want. The TC would only add minimal bulk.

@ Lowell: Thanks for the idea. I've owned the M135 twice, and it is a solid lens. However, the problem is I want the 70 Ltd as part of the kit, and the extra length is for those times I need a bit more. So, I dumped the M135 because it was an extra lens, not a replacement for the DA 70. You mentioned the 4-element is not a good option...is there a better option when it comes to TCs?
another good option would be the SMC-F 1.7x AF TC. you will use the teleconverter AF elements not the lenses' but this is a much better TC than a 4 element unit, but the same size as a 4 element 2X TC.

I use mine on my 85mm F1.4 to get a 145mm F2.5 lens. That is worth while for the times I need it
09-02-2010, 08:47 PM   #7
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QuoteOriginally posted by gnaztee Quote
@ pacerr: Thanks for the reply. I've owned the 50-200 before, and now own the 55-300. I'm not willing to give up the 70 Ltd's image quality for a zoom, so to get more reach with the zoom it would have to be in addition to the 70, which makes the kit bigger than I want. The TC would only add minimal bulk.
True, but I thought you said you really wanted a DA135? The DA50-200 is no bigger or heavier than the M135/3.5. The maximum aperture of the DA50-200 at 135mm is about the same as that of the DA70 with a 2X TC, and the zoom's IQ is probably a lot better than that of the DA70 with a TC. It's also more convenient to change lenses than to add and remove a TC, not to mention the extra flexibility of the zoom.

QuoteQuote:
@ Lowell: Thanks for the idea. I've owned the M135 twice, and it is a solid lens. However, the problem is I want the 70 Ltd as part of the kit, and the extra length is for those times I need a bit more. So, I dumped the M135 because it was an extra lens, not a replacement for the DA 70.
Again, I'm having trouble reconciling this with your original statement that you really want a DA135. If you'd be OK with the DA135, why not the M?
09-02-2010, 11:03 PM   #8
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Marc, fair question. If there were an autofocus DA 135, I would completely rearrange the small primes that are my traveling kit. I just don't like manual focus enough to rearrange to fit the M 135 in the bag. For example, with what I have now I'd take the DAs 21-35-70-(possible TC). If a DA 135 existed, I'd go 21-50-135, or 15 (which I don't have)-35-135. Basically, I'm trying to stay with a 3-lens kit, but the Vivitar TC looked thin enough to squeeze it in.

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