18th April 2004, 08:33 AM
Any one heard of GroBartiG Teleconverter and wide angle converters b4?
this thread here http://forums.clubsnap.org/showthread.php?t=70737
There is a seller selling GroBartiG 2.5x Teleconverter and 0.5x wide angle converter. Are these converters good in terms of make and optical performance? tried searching on the net for info but to no avail.
18th April 2004, 12:10 PM
I've haven't seen the quality out of a GroBartiG product before, but the 2.5x tele and 0.5x wide seem too good to be true. I once bought a Vitacon teleconverter with a long tele, and ended up being very disappointed with the results. Most 'good' teleconverters have a range from 1.5x to 2.0x, and for wide angle about 0.7x.
What camera are you using?
When I had a Canon prosumer digicam (G5), I searched the web extensively for teleconverters and wide-angle converters. The brands which you should look at are Kenko, Raynox (both lower to mid range), Tiffen (mid to high range), Olympus and Canon (high range). I'd persoally favour the Raynox ones if you're on budget (order from the USA), and the Olympus and Canon ones if you have the money.
I would not even consider brands such as Vitacon, because although they are cheaper and offer more telephoto magnification or wide angle, the quality of the glass is poor. Your resulting images will have visible chromatic aberrations, and the colours will 'bleed'.
Don't compromise on quality. Remember to do test shots before buying, and zoom in all the way for signs of colour bleeding and other irregularities.
A useful links:
You can check out this guy's website. He did a review for G3 teleconverters and wideangle converters. It's here. His main site has more details and stuff.
18th April 2004, 12:31 PM
I have posted a sample picture with and without the tele lens at this URL. You can use this to gauge the performance of the lens.
18th April 2004, 12:32 PM
Was using a tripod with my A70 for the test shots. Pictures are not edited.
18th April 2004, 12:36 PM
presuming both are taken from the same distance, the telconverter is actually 1.3x-1.32x.
Last edited by mpenza; 18th April 2004 at 12:57 PM.
18th April 2004, 10:12 PM
jjtml, any comments on the actual magnification of the GroBartiG tele convertors? from your sample pictures, I concur with mpenza that it doesn't seems to be 2.5x? Can post samples of the wide angle convertor as well? Preferably of outdoor landscape pics in the sun, not resized downwards for closer examination.
A suggestion for the tele lens test would be one at Zero zoom for the camera, one at the max(optical) zoom of the A70 without tele lens, and finally one of the A70 at max (optical)zoom with the Tele lens.
Wide angle convertor test can just simply be one with and one without the convertor will do.
I'm interested to buy, but need more assurance on the actual zoom/wide factor and the optical performance if you understand.
Test pictures in brightly sunlit conditions will help in the judgement of any possible CA/PF caused by the convertors.
18th April 2004, 10:39 PM
I've done a measurement using a ruler on the screen and the magnification factor is about 1.3x-1.33x . I've posted more pictures for reference, hang on will post the url in my next post while i resize them and arrange them in a webpage.
18th April 2004, 10:59 PM
Hi, I've just uploaded more pictures for you bros to see. Click on this link. Quite heavy on the download unless you're on broadband.
18th April 2004, 11:28 PM
hmmm....the images with the convertors on seems pretty soft, even after resized to such smaller sizes.
18th April 2004, 11:40 PM
doesn't look like .5× wide-conversion.
18th April 2004, 11:53 PM
.5x is just advertised. I think it's around .6x-.7x . It's hard to find manufacturers nowadays who quote accurate specs (especially in PC Hardware!)
18th April 2004, 11:58 PM