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08-03-2011, 07:46 AM   #1
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Tele converter advice, best zoom lenses

Hi again.

I just bought a used vivatar 2x tele converter but it don't seem to make thing closer with my DA 50-200 lense. Is that not what is ment to do?

The other is, When i check the photo, it come out black, why is this?

Instead of me starting a new topic, can someone please recommend a good upto 300mm zoom lense. ?

These any good?


Sigma 70-300mm
Tamron AF 70-300mm
Pentax SMC Zoom Lens FA J 75mm-300mm
Or the standard PENTAX DA-L 55-300mm.

Thanks

08-03-2011, 08:15 AM   #2
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Well that is a nice thing for your desk to hold paper.

The 2x TC takes light. So your DA 50-200mm is at 200mm f5.6 making it 400mm f11.2 and thus is your lightmetering and AF not working any more.
08-03-2011, 08:26 AM   #3
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Yes, that is what it is meant for. It should give you a 100 - 400 zoom.

However, it does that at the expense of about 2 stops of light. And since it is all manual you lose aperture control and auto-focus. You will need to shoot in all manual and control the aperture using the aperture ring on the lens. I do not have that lens, but I do not think it has an aperture ring so that is a problem.

Unless you have a tele-converter that is auto-focus but I am assuming yours is not.
08-03-2011, 08:42 AM   #4
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Does the TC have contact pins on it that match the pins on your lens? If not, it is a non-A-type TC; the lens aperture will remain fully stopped-down, and your pictures will be black. Such a TC can only be used with lenses that have aperture rings. An A-type TC will work on your lens and may cost less than US$25. Neither of these supports autofocus; AF TCs are rather rare and costly. And all too many TCs reduce image quality. You'll usually get better images just by cropping.

Lenses: The DA 55-300 is well regarded and not too expensive. The old FA100-300 (silver) is also well-liked and can be found for around US$100. I can't comment on the other lenses you mentioned. For more reach, think about a 500mm mirror lens -- not a zoom, but compact and sometimes inexpensive. Good luck!

08-03-2011, 09:11 AM   #5
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Regarding the Tamron AF 70-300mm, I have a wonderful copy that has prevented me from buying the DA55-300 that I hear great things about.

Specifically I have the model A17 Tamron AF 70-300mm 1:4-5.6 TeleMacro (1:2), the one with the Normal/Macro switch on the body and fine ridges on the focus and zoom rings.

Previously I owned an older version of Tamron 70-300 lens and this version is leaps and bounds sharper than the old version (old version has no switch and smooth zoom and focus rings.)

There are better more expensive options but this lens has very good performance vs cost.

Sample:

08-03-2011, 10:08 AM   #6
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QuoteOriginally posted by jatrax Quote
Yes, that is what it is meant for. It should give you a 100 - 400 zoom.

However, it does that at the expense of about 2 stops of light. And since it is all manual you lose aperture control and auto-focus. You will need to shoot in all manual and control the aperture using the aperture ring on the lens. I do not have that lens, but I do not think it has an aperture ring so that is a problem.

Unless you have a tele-converter that is auto-focus but I am assuming yours is not.
The TC don't have any movable ring on it or auto focus. I have tried all in manual mode but no luck. Unless I am doing it wrong.

QuoteOriginally posted by RioRico Quote
Does the TC have contact pins on it that match the pins on your lens? If not, it is a non-A-type TC; the lens aperture will remain fully stopped-down, and your pictures will be black. Such a TC can only be used with lenses that have aperture rings. An A-type TC will work on your lens and may cost less than US$25. Neither of these supports autofocus; AF TCs are rather rare and costly. And all too many TCs reduce image quality. You'll usually get better images just by cropping.

Lenses: The DA 55-300 is well regarded and not too expensive. The old FA100-300 (silver) is also well-liked and can be found for around US$100. I can't comment on the other lenses you mentioned. For more reach, think about a 500mm mirror lens -- not a zoom, but compact and sometimes inexpensive. Good luck!
The TC has only one pin on it but I don't know what that does. So I have the wrong TC by the looks of it then. Thanks for the advice on zoom lenses. I bought the TC because it was ment to be cheaper than buying a better zoom lense.
08-03-2011, 10:18 AM   #7
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Thanks crewl1, will keep an eye out for a cheap one off aution website.

I have just tried my rubbish chinon lense with the TC and photo come out ok. But then the chinnon does have a aperture ring, not like my DA 50-200mm lense.
08-03-2011, 10:46 AM   #8
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Those cheap 2x converters make better extension tubes for macro than their intended purpose, by removing all the glass elements inside. See the thread https://www.pentaxforums.com/forums/lens-clubs/143202-macro-any-means-necessa...ml#post1499482

08-03-2011, 10:56 AM   #9
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TC work best on fast primes. About the only zooms where TC (esp a 2X) would be viable would be something like a fast 70-200 f2.8 zoom.

But TC not only rob you of light, they also steal resolution from the lens too. The amount of resolution lost depends on the quality of the TC, but even the best TC will force a visible drop in sharpness.

Speaking from experience with just a 1.4 TC on various regular zooms - Tamron 70-300, DAL 55-300, old Sigmas etc. Results were very poor.
08-04-2011, 01:45 AM   #10
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I recently put my cheap (manual) 2x TC to the test. I have a DA 55-300, and took these two shots across a field. The first is at 300mm with the TC (ie 600mm), the second is 300mm without the TC and then cropped to roughly the same dimensions. Both were shot wide open (f/11.6 with the TC and f/5.8 without; my TC has an aperture lever, which works like any M or K lens, ie only wide open on my Kr).

300mm with TC
300mm cropped

As you can see, the cropped shot is much clearer and sharper. I haven't adjusted anything, just cropped. Obviously neither is a very good shot anyway, it was just a quick test. The TC shot was manually focused too, which probably didn't help. With better technique, a tripod and more post-processing you might get the TC shot a bit better, but the crop is always going to win out in equal conditions (better resolution, less light loss to compensate for). Maybe with a high quality TC on a high quality lens it might be worth it. Or if you get a 500mm mirror and want to become a private investigator

For the record, the DA 55-300 is pretty darn good. I had a Tamron 70-300 Macro, which I part-exchanged for the DA. The macro function was great, and the image quality was almost as good as the DA, but the AF was slow, noisy and hunted around a heck of a lot. Might have just been a duff copy though; my fiancee has the same lens for her Nikon and it's pretty good at AF (still a bit noisy though). The DA has Quick-Shift manual focusing too, which I love.

Last edited by Joe Nation; 08-04-2011 at 01:52 AM.
08-04-2011, 04:02 AM   #11
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QuoteOriginally posted by Ducks Quote
Hi again.

I just bought a used vivatar 2x tele converter but it don't seem to make thing closer with my DA 50-200 lense. Is that not what is ment to do?

The other is, When i check the photo, it come out black, why is this?
Hi
Wouldn't it be great if you could buy something for cheap that really, really works like it was something really, really expensive.

This applies to TCs like nothing else does. Cheap TCs work of course but they bugger up your pictures something terrible.

I purchased a Pentax - AF 1.7X TC because I wanted to have the occasional longer reach for my PENTAX 60-250 DA* without having to carry another bigger, heavier lens and for me at least here in this context the TC makes a lot of sense. This TC is not cheap but it is auto everything and on the 60-250 it produces very high quality IQ. Because of the high IQ this TC produces I thought the money was well spent. See sample below.

One draw back is, they are very popular, Pentax can't keep up with supply they are leftovers from the film days (but are still made now) and consequently keep going up in price. If you look you can find one.

The enclosed sample pics, believe it or not, were hand held and in PP I only adjusted the black point a little and applied some light sharpening. Originals were shot in RAW. (I only shoot RAW)

Greetings

Last edited by Schraubstock; 10-31-2011 at 07:14 AM.
08-04-2011, 12:45 PM   #12
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Nice sharp photos schraubstock.

Well i nearly won a SIGMA 70-300 DL Macro Super F4- 5.6 today but outbid at the last moment.


QuoteQuote:
Speaking from experience with just a 1.4 TC on various regular zooms - Tamron 70-300, DAL 55-300, old Sigmas etc. Results were very poor.
Surely one of them must be ok. I have heard that pentax seem to come out on top in most cases.

What do you make of this? 500mm S f8.0 Lens for Pentax *istDL2 *istDs DL *istD | eBay

Do you think that looks cheap?
08-04-2011, 01:38 PM   #13
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QuoteOriginally posted by Ducks Quote
Surely one of the [TCs] must be ok. I have heard that pentax seem to come out on top in most cases.
Pentax did make some of the best TCs back in the days of manual focus lenses. Pentax produced a couple of TCs that only worked with their telephoto lenses and may have been the best ever made. None of those TC will even fit on todays consumer grade telephoto lenses. The next best TC option is aforementioned F 1.7x; but that can be hard to find and expensive when found (I've seen it go for over $400 on ebay). Furthermore, consumer grade zoom lenses, even the better ones, don't have a huge amount of resolution to spare on the long end of the lens. So while the F 1.7x might give very nice results on an expensive pro telezoom like the DA* 60-250 (it can take a hit on resolution because it's already pretty darn sharp), on a cheap consumer grade lens it's not going to do so well.
08-04-2011, 03:10 PM   #14
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I would put a 2x teleconverter only on a f2.8 lens. I have a pentax 55-300 and a tamron 1.4x teleconverter. When i use the teleconverter on any lens, i set the focus manual to infinity before i take the picture. when I do this on the lens with the teleconverter the af does not hunt.

i am posting a picture with a tamron 1.4x teleconverter and pentax 55-300mm lens.


08-04-2011, 09:39 PM   #15
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QuoteOriginally posted by Ducks Quote
Nice sharp photos schraubstock.

Well i nearly won a SIGMA 70-300 DL Macro Super F4- 5.6 today but outbid at the last moment.




Surely one of them must be ok. I have heard that pentax seem to come out on top in most cases.

What do you make of this? 500mm S f8.0 Lens for Pentax *istDL2 *istDs DL *istD | eBay

Do you think that looks cheap?
These cheap "Ground to Air rocket launchers" have been available for yonks on e-bay. Can't pass judgement as to their IQ quality, but personally I would not be seen walking around with one of these, size and weight, holy crap, have this in your hand for a few hours and your arm will be stretched long enough to tickle the soles of your feet without bending over.

Pentax a few years ago started to sell these 1.7 TCs from old stock they had left over from the film days when it was discovered by DSLR owners what high quality they were and how exceptionally well they worked with DSLRs. Ever since they have become more and more expensive. I understand that PENTAX have started a limited production for them (but I could be wrong). This I was told by my Japanese friends. I purchased one 2 years ago during one of my frequent visits to Japan. I paid some US$250.00 if I remember, now you have a hard time to get one for under $400.00. (Oh well, should have bought the total stock holding)

Originally posted by Ducks
"Furthermore, consumer grade zoom lenses, even the better ones, don't have a huge amount of resolution to spare on the long end of the lens. So while the F 1.7x might give very nice results on an expensive pro telezoom like the DA* 60-250, on a cheap consumer grade lens it's not going to do so well.
"

So very true indeed, but there is no substitute for quality unfortunately. Generally speaking (but by all means not always) there is a direct relationship between price and quality.

Greetings
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