M Vers wrote:
In addition to the above, for your enlightenment, not all TCs are designed with a protruding element and, believe it or not, not all TCs are made by Canon. Such TCs can be used with most lenses without any modification or use of extension tubes.
The reason the high-quality teleconverters/extenders from Canon and Nikon have the protruding front element is to minimize vignetting with telephoto lenses.
The cheaper third-party teleconverters may fit more lenses, but all of the ones I've tried (Tamron, Kenko, Sigma) vignette rather badly on longer lenses.
molson wrote:
The reason the high-quality teleconverters/extenders from Canon and Nikon have the protruding front element is to minimize vignetting with telephoto lenses.
The cheaper third-party teleconverters may fit more lenses, but all of the ones I've tried (Tamron, Kenko, Sigma) vignette rather badly on longer lenses.
I understand why Canon/Nikon TCs are designed the way they are, but that has nothing to do with the point I was making. Whether or not TCs were designed specifically for use with telephoto lenses is irrelevant.
I've not seen much extra vignetting with my Kenko 1.4x on my superteles. Can't say I've noticed it at all really. I'm sure it's there but it's not an issue whatsoever.
Pixel Perfect wrote:
I've not seen much extra vignetting with my Kenko 1.4x on my superteles. Can't say I've noticed it at all really. I'm sure it's there but it's not an issue whatsoever.
Especially when shooting slightly stopped down. Still, regardless of the whole vignetting thing, the point is macro lenses can and do perform very well in conjunction with many TCs...it's plain ignorant to claim otherwise. In the end who really cares what something was or wasn't designed for; if it works, it works.
It doesn't seem like anyone mentioned it, so I will: how about a 300mm f/4L IS? If you're looking to really get close this probably isn't the best choice, but for full body shots of dragonflies, it might do the trick. It's a good lens for butterflies. It seems to work for that better for me than my 100mm Macro for this particular kind of photography, but I'm no expert.
