tele converters

Has anyone had any experience of a Vivatar Macro Focusing 2x converter? if so, good or bad?
I don't have available cash for a Sigma 50-500 or 150-500 so thought about a tele converter. One of these are for sale on ebay for £85 or best offer. The seller has described it as having 7 elements in 7 groups, which reading another thread was suggested as being reasonable unlike cheap tcs that only have 4 elements.
I am aware of the two pentax 1.7x converters on ebay, but can't stretch to the price of them.
Any comments wil be greatly appreciated.

Probably OK for macro, but I wouldn't use it for
telephoto. Your better off with a 1.4 to 1.7x
for telephoto. Which lens is it for?

I would be using it with my FA 80-320mm on a k5 body.

I wouldn't consider using a teleconverter with that lens. at 320mm the aperture will double to f/11ish.

Shouldn't really use a teleconverer on any lens over f/4 really.

i have used the kenko macro tc and it was ok but i now have the kenko kax mc 7 which i have used with zoom lens and in good light work ok on my k20 lenny bloke was selling a pentax 2x-s tc and i hear that thease are ok to

phill

I have the same Vivitar 2X macro teleconverter, though mine is the PK mount and the one you are looking at is PK A. It's excellent when used with a Pentax 50mm manual prime for macro, but rubbish combined with a longer lens for extra reach. It's not a criticism of the converter, it's simply not designed for that.

It's also manual focus only so wouldn't give you auto-focus on the FA 80-320mm.

Hi Champywoo, Please don't take this as a blatant attempt by me to promote my items for sale - but as Reso kindly mentioned I have one for sale then here are my views:

Generally speaking the 7 element converters are better than the 4 element ones, and amongst the 7 element ones I have generally had good results with the Teleplus MC7 and my best results have been with the Pentax A 2X-S. The Pentax A 2X-S was designed by Pentax for lenses up to a focal length of 300mm (there is a 2X-L for 300mm+ lenses). I did own a Macro Converter a long time ago but replaced it with Macro lenses soon after.

Quality does tend to reduce the longer the lens (as milamber said - used with a 50 they are very good) and with a zoom the top end is quite often not as good as the shorter end anyway even without a converter.

I've got one, and as others have said it works reasonably for macro. Despite the focusing scale suggesting it will work at infinity, mine is soft enough at long distances that focus confim will not ever light, and even my eyesight has to agree!

Results with my mirror lenses have certainly proved better for distant work. I've had both 500mm & 600mm mirror lenses, while neither were a patch on the Bigmos (Sigma 150-500) they cost less than the TC your after, and I suspect are about the only reasonable way you'll get beyond 320mm without paying a fortune...

Hi Simon

I do not have experience with the teleconverters listed above but have a Super Paragon mf 2x converter.

With shorter focal lenses (as mentioned above) it may on a good day be described as ok (maybe) and with my telehoto lenses it is not good in my experience.

It may be that I just can't use it correctly - it may be that it is not a great example of a teleconverter and I have no idea how many elements it has.

However, if you live or find yourselef anywhere near Wrexham we could meet up and try it out if you want to.

Incidentally, it's not an item I intend to list for sale as I doubt it's true worth is much more than (or maybe less) than a decent bag of fish and chips

Regards


Stu

Hi Simon

A friend at work has the Vivitar Macro Focussing TC, but doesn't use it very much. I would guess it is similar in quality to the 7 element Teleplus MC7 that I own; this is a good quality TC but must be used with prime lenses (I've had excellent results with a 50mm and a 105mm Macro, but it's totally useless with my 55-300). The one you describe is massively overpriced at £85; I would guess it's worth nearer the £40 mark?

Regards
David

I was going to say the same in my post, David, but when I checked on Ebay this is a PK A converter, not the usual PK one. 40 pounds would be about right for the PK. Haven't seen a PK A before so 85 might be the going rate?

Still isn't the right converter for the job, though

The PKA ones are not so rare; my friend at work paid about £35 for his and I paid £30 for my PKA Teleplus MC7. I still think £40 is the mark? Maybe one of the more knowledgeable members with regard to lens sales can advise?

Regards
David

Pka are usually around £30-40ish af one will be more..