How to test a teleconverter? URGENT!

Hi guys! In about two days I will purchase a teleconverter for my G6. As far as i understood no matter what teleconverter i will choose I need the LA-DC58D Conversion lens adapter from Canon. I will choose between the Giottos LN52201AS - Adaptor Tele x2 ( 52mm ) teleconverter and the Kenko Telephoto Conversion Lens LD-20T. My question is how should I test the teleconverters? What should I be looking for in order to find out which one is the best? I thought of testing them by taking 2 or 3 pictures with each at max telephoto. Should I also take some pictures at mid telephoto? Is it ok if i only check the pictures on the G6's display? Hope you can help me. IT'S PRETTY URGENT. THANX.

After much online searching and research, I bought the 58mm Canon brand teleconverter for the G6 about a month ago. For me, the ultimate test was taking photos at various settings, viewing them on my PC, and printing out selected images at various distances. In my opinion, having the sharpest image at the greatest distance was key. So far, the Canon unit has been great and gives razor sharp images.

Unfortunately, I'm not familiar with the units you have in mind.

I have Kenko and it is a great lens...and I am also selling it, so if you decide on purchasing that lens contact me because it is brand new.

As far as testing I would go with Gardenstates words...look for sharpness and, depending on what distance you wanna use it, check for vigneting...they all have vigneting, some more and some less.

Regards,

About 2 years ago I bought the Kenko teleconverter and sent it right back for a refund (less a restocking fee). I have a G2 and on the camera LCD the images looked quite good but not on my computer screen. Way too much chromatic abberation. No edge was a single color. Packed it up and shipped it back. Maybe the Canon is good, I haven't tried it. Wanted to save some money but it shows. Used the Lensmate adaptor.

Stans,

I also had the Kenko, but did not observe any of the symptoms you mentioned.

Razor sharp images with no visible deterioration against the normal G2 image in daylight, and only a slight impact on images at night shots. I used it with the corresponding Kenko adapter - so I assume that maybe the distance to the lens with the lensmate adapter was not correct.

Suedezu,

As to the original question ... take images at full tele, because at intermediate settings, both lenses will have vignetting. Maybe one less than the other - if this is important for you, also test it.

Pay special attention to the sharpness, aberration etc. in the corners, because that's where it is more visible.

Best regards,
Andy